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0. Collective flavor conversions are interactions of neutrinos with quantized flavor wavesid:2502.06935:id在线阅读
Damiano F. G. Fiorillo, Georg G. Raffelt
Collective oscillations in dense neutrino gases (flavor waves) are notable for their instabilities that cause fast flavor conversion. We devel...点击展开阅读
0. Collective flavor conversions are interactions of neutrinos with quantized flavor wavesid:2502.06935:id在线阅读
Damiano F. G. Fiorillo, Georg G. Raffelt
Collective oscillations in dense neutrino gases (flavor waves) are notable for their instabilities that cause fast flavor conversion. We develop a quantum theory of interacting neutrinos and flavor wave quanta, which are analogous to plasmons, but also carry flavor. The emission or absorption of such flavor plasmons $\psi$, or flavomons, changes the neutrino flavor. When an angular crossing occurs, the process $\nu_\mu\to\nu_e+\psi$ is more rapid than its inverse along the direction of the crossing, triggering stimulated $\psi$ emission and fast instability. Calculating the rate via Feynman diagrams matches the fast instability growth rate. Our novel $\nu$ and $\psi$ kinetic equations, corresponding to quasi-linear theory, describe instability evolution without resolving the small scales of the flavomon wavelength, potentially overcoming the main challenge of fast flavor evolution.
致密中微子气体中的集体振荡(味道波)因其不稳定性而引人注目,这种不稳定性会导致快速的味道转换。我们发展了一种关于相互作用的中微子和味道波量子的量子理论,它们类似于等离子体,但也携带味道。这种味道质子$\psi$或味道子的发射或吸收会改变中微子的味道。当发生角交叉时,沿交叉方向的$\nu_\mu\to\nu_e+\psi$过程比它的逆过程更快,从而引发受激的$\psi$发射和快速不稳定性。通过费曼图计算出的速率与快速不稳定性的增长速率相吻合。我们新颖的$\nu$和$\psi$动力学方程与准线性理论相对应,描述了不稳定性的演化,而无需解决黄门波长的小尺度问题,从而有可能克服快速味道演化的主要挑战。
1. All axion dark matter from supersymmetric modelsid:2502.06955:id在线阅读
Howard Baer, Vernon Barger, Dibyashree Sengupta, Kairui Zhang
Supersymmetric models accompanied by certain anomaly-free discrete R-symmetries Z_n^R are attractive in that 1. the R-symmetry (which can arise from compactified string theory as a remnant of the broken 10-d Lorentz symmetry) forbids unwanted superpotential terms while allowing for the generation of an accidental, approximate global U(1)_{PQ} symmetry needed to solve the strong CP problem and 2. they provide a raison d'etre for an otherwise ad-hoc R-parity conservation. We augment the minimal supersymmetric Standard Model (MSSM) by two additional Z_n^R- and PQ-charged fields X and Y wherein SUSY breaking at an intermediate scale m_{hidden} leads to PQ breaking at a scale f_a\sim 10^{11} GeV leading to a SUSY DFSZ axion. The same SUSY breaking can trigger R-parity breaking via higher-dimensional operators leading to tiny R-violating couplings of order (f_a/m_P)^N and a WIMP quality problem. For Z_4^R and Z_8^R, we find only an N=1 suppression. Then the lightest SUSY particle (LSP) of the MSSM becomes unstable with a lifetime of order ~ 10^{-3}-10 seconds so the LSPs all decay away before the present epoch. That leaves a universe with all axion cold dark matter and no WIMPs in accord with recent LZ-2024 WIMP search results.
伴随着某些无反常离散R对称性Z_n^R的超对称模型很有吸引力,因为:1.R对称性(可以作为被打破的10-d洛伦兹对称性的残余从紧凑弦理论中产生)禁止了不需要的超势项,同时允许产生解决强CP问题所需的偶然的、近似的全局U(1)_{PQ}对称性;2.它们为其他临时的R-奇偶性守恒提供了存在的理由。我们通过两个额外的Z_n^R-和PQ-电荷场X和Y来增强最小超对称标准模型(MSSM),其中SUSY在中间尺度m_{hidden}上的破缺导致PQ在尺度f_a\sim 10^{11} GeV上的破缺,从而导致SUSY在尺度f_a\sim 10^{11} GeV上的破缺。GeV 引发 SUSY DFSZ 轴子。同样的SUSY破缺可以通过高维算子引发R-奇偶性破缺,导致(f_a/m_P)^N阶的微小R-违反耦合和WIMP质量问题。对于 Z_4^R 和 Z_8^R,我们发现只有 N=1 的抑制。那么MSSM中最轻的SUSY粒子(LSP)就会变得不稳定,其寿命约为10^{-3}-10秒,因此LSP在本纪元之前就会全部衰变掉。这样一来,宇宙中就只剩下轴心冷暗物质,而没有WIMPs了,这与最近的LZ-2024 WIMP搜索结果是一致的。
2. Conformal Freeze-in Dark Matter: 5D Dual and Phase Transitionid:2502.06965:id在线阅读
Lillian Luo, Maxim Perelstein
Conformal Freeze-in (COFI) scenario postulates a dark sector described by a conformal field theory (CFT) at energies above the ``gap scale" in the keV$-$MeV range. At the gap scale, the dark CFT undergoes confinement, and one of the resulting bound states is identified as the dark matter candidate. In this paper, we study this model in the context of the AdS/CFT correspondence with a focus on the mechanism of the infrared (IR) breaking of conformal invariance in the dark sector. We construct the holographic dual to the conformal dark sector, given by a Randall-Sundrum-like model in 5D, where the Standard Model (SM) fields and the dark matter candidate are placed on the ultraviolet (UV) and IR branes respectively. The separation between the UV and IR branes is stabilized by a bulk scalar field, naturally generating a hierarchy between the electroweak scale and the gap scale. We find that the parameter space of COFI comprises two distinct branches of CFT's living on the Anti-de-Sitter (AdS) boundary, each corresponding to a different UV boundary condition. The two branches of CFT's result in different radion potentials. The confinement of the CFT is dual to the spontaneous symmetry breaking by the 5D radion potential. We then use this dual 5D setup to study the cosmological confining phase transition in the dark sector. We find the viable parameter space of the theory which allows the phase transition to complete promptly without significant supercooling.
共形冻结(COFI)方案假定在 "间隙尺度";keV$-$MeV范围 "以上的能量中存在一个由共形场论(CFT)描述的暗部门。在 "间隙尺度",暗CFT发生约束,由此产生的束缚态之一被确定为暗物质候选态。在本文中,我们在 AdS/CFT 对应的背景下研究了这个模型,重点是暗扇区共形不变性的红外(IR)破缺机制。我们构建了保角暗部的全息对偶,由 5D 的兰德尔-桑德鲁姆(Randall-Sundrum-like)模型给出,其中标准模型(SM)场和暗物质候选分别置于紫外(UV)和红外支线上。紫外支链和红外支链之间的分离由一个体标量场来稳定,自然产生了电弱尺度和间隙尺度之间的层次结构。我们发现,COFI 的参数空间包括生活在反德西特(AdS)边界上的两个不同的 CFT's 分支,每个分支对应于不同的紫外边界条件。这两个 CFT's 分支导致了不同的放射势。CFT 的约束与 5D 放射势的自发对称破缺是对偶的。然后,我们利用这种双 5D 设置来研究暗部门的宇宙学约束相变。我们找到了理论的可行参数空间,它允许相变在没有明显过冷的情况下迅速完成。
3. Constraining the SMEFT Extended with Sterile Neutrinos at FCC-eeid:2502.06972:id在线阅读
Patrick D. Bolton, Frank F. Deppisch, Suchita Kulkarni, Chayan Majumdar, Wenna Pei
We investigate how extensions of the Standard Model (SM) involving heavy neutral leptons (HNLs) can be probed at FCC-ee, the proposed high-energy circular $e^+e^-$ collider. Using the effective field theory (EFT) approach, we determine the impact of new interactions on the production and decay of HNLs at FCC-ee. In particular, we consider $d\leq 7$ $\nu$SMEFT operators which induce vector, scalar and tensor four-fermion and effective charged- and neutral-current interactions of HNLs, that may also mix with the active neutrinos of the SM. We consider sensitivities to the active-sterile mixing and EFT Wilson coefficients from monophoton searches and displaced vertex decay signatures. In both analyses, we consider the scenarios where HNLs are Majorana or Dirac fermions. We translate the upper bounds on the Wilson coefficients to lower limits on the scale of new physics and examine the implications for tree-level ultraviolet completions.
我们研究了如何在拟建的高能环形$e^+e^-$对撞机FCC-ee上探测标准模型(SM)涉及重中性轻子(HNLs)的扩展。利用有效场论(EFT)方法,我们确定了新的相互作用对HNLs在FCC-ee的产生和衰变的影响。特别是,我们考虑了$d\leq 7$ $\nu$SMEFT算子,这些算子诱发了HNLs的矢量、标量和张量四费米子以及有效的带电和中性电流相互作用,它们也可能与SM的主动中微子混合。我们考虑了单光子搜索和位移顶点衰变特征对有源中微子混合和 EFT 威尔逊系数的敏感性。在这两项分析中,我们都考虑了 HNL 是马约拉纳费米子还是狄拉克费米子的情况。我们将威尔逊系数的上限转化为新物理尺度的下限,并考察了树级紫外补全的影响。
4. WilloWISPs: A New Dark Growth Channel for Black Holes Suggests a Full-Spectrum Hierarchical MACHO Mass Function for Dark Matterid:2502.06981:id在线阅读
Zachary R. Smith, Neil F. Comins
Evidence of neutron stars with deconfined quark-matter cores suggest a new pathway for the evolution of black holes. New theories about the cores of neutron stars support the idea that quarkonium is likely to grow there as the neutron star ages. Surveys of stellar remnants have shown that there is no major mass gap between neutron stars and black holes. Black holes, specifically primordial ones (PBHs), have been suggested as an explanation for dark matter before. However, the way that very large black holes can form in the lifetime of the visible universe has only recently been explained with the solution to The Final Parsec Problem. If neutron stars can become exotic stars or black holes, then they may persist long enough to quiescently provide enough mass in dense matter regions to allow Intermediate-Mass Black Holes (IMBH) and Supermassive Black Holes (SMBH) to form quickly via coalescence. We find that a hierarchical clustering of Massive and Compact Halo Objects (MACHOs) with axion-dominated mini-halos can help to explain all of the missing dark matter. The model presented here suggests that this type of MACHO is likely equivalent to black holes above an unknown critical mass, which is less than ~5 $M_{\odot}$, and that they ought to form quark stars below this mass. If quark stars are a metastable transition between neutron stars and black holes, then black holes ought to be equivalent to boson stars with event horizons, after all the residual quark material has formed a Bose-Einstein condensate of mesons.
中子星具有去封闭夸克物质内核的证据表明,黑洞的演化有了新的途径。关于中子星内核的新理论支持这样一种观点,即随着中子星的老化,夸克物质很可能在中子星内核生长。对恒星残骸的调查表明,中子星和黑洞之间并不存在重大的质量差距。黑洞,特别是原始黑洞(PBHs),曾经被认为是暗物质的一种解释。然而,超大型黑洞在可见宇宙的生命周期内形成的方式,直到最近才通过 "最终视小秒针问题"(The Final Parsec Problem)的解决方案得到解释。如果中子星可以变成奇异恒星或黑洞,那么它们可能会持续存在足够长的时间,以便在致密物质区域静态地提供足够的质量,让中质量黑洞(IMBH)和超大质量黑洞(SMBH)通过凝聚迅速形成。我们发现,大质量和紧凑光环天体(MACHOs)与轴子主导的小光环的分级聚类有助于解释所有缺失的暗物质。这里提出的模型表明,这种类型的MACHO很可能等同于超过未知临界质量的黑洞,临界质量小于~5 $M_{\odot}$,而且它们应该形成低于这个质量的夸克星。如果夸克星是介于中子星和黑洞之间的一种可转移过渡,那么在所有残余夸克物质形成介子的玻色-爱因斯坦凝聚态之后,黑洞应该等同于具有事件视界的玻色子星。
5. Collider Prospects for the Neutrino Magnetic Moment Portalid:2502.07024:id在线阅读
Vedran Brdar, Ying-Ying Li, Samiur R. Mir, Yi-Lin Wang
The transition magnetic moment between active and sterile neutrinos is theoretically well-motivated scenario beyond the Standard Model, which can be probed in cosmology, astrophysics, and at terrestrial experiments. In this work, we focus on the latter by examining such an interaction at proposed lepton colliders. Specifically, in addition to revisiting LEP, we consider CEPC, FCC-ee, CLIC, and the muon collider, motivated by the potential realization of any of them. Within the effective field theory framework, we present parameter regions that can be probed, highlighting the dependence on the lepton flavor interacting with the sterile neutrino. By including several new processes with large sterile neutrino production cross sections at high-energy lepton colliders, we find that the expected sensitivity for the active-to-sterile neutrino transition magnetic moment can reach $d_\gamma \simeq \mathcal{O}(10^{-7})$ GeV$^{-1}$.
有源中微子和无源中微子之间的过渡磁矩是超越标准模型的理论依据,可以在宇宙学、天体物理学和地面实验中进行探测。在这项工作中,我们将重点放在后者,在拟建的轻子对撞机上研究这种相互作用。具体地说,除了重温 LEP 之外,我们还考虑了 CEPC、FCC-ee、CLIC 和μ子对撞机,其动机是其中任何一个对撞机都有可能实现。在有效场论框架内,我们提出了可以探测的参数区域,强调了与无常中微子相互作用的轻子味道的依赖性。通过在高能轻子对撞机中加入几个具有大无常中微子产生截面的新过程,我们发现有源到无常中微子转变磁矩的预期灵敏度可以达到 $d_\gamma \simeq \mathcal{O}(10^{-7})$ GeV$^{-1}$。
6. Accelerating Berends-Giele recursion for gluons in arbitrary dimensions over finite fieldsid:2502.07060:id在线阅读
Juan M. Cruz-Martinez, Giuseppe De Laurentis, Mathieu Pellen
This work provides a proof of concept for the computation of pure gluonic amplitudes in quantum chromodynamics (QCD) on graphics processing units (GPUs). The implementation relies on the Berends-Giele recursion algorithm and, for the first time on a GPU, enables the numerical computation of amplitudes in an arbitrary number of space-time dimensions and over finite fields. This demonstrates the advantages of hardware acceleration, not only for the computation of tree-level amplitudes for real-radiation processes in four dimensions over complex numbers but also for generating loop integrands for virtual corrections in $d$ dimensions over finite fields. The associated computer program is publicly available.
这项工作提供了在图形处理器(GPU)上计算量子色动力学(QCD)中纯胶子振幅的概念验证。该实现依赖于贝伦斯-盖尔递归算法,并首次在 GPU 上实现了在任意时空维数和有限场上的振幅数值计算。这证明了硬件加速的优势,不仅适用于计算复数上四维实辐射过程的树级振幅,还适用于生成有限域上$d$维虚拟修正的环积分。相关计算机程序已公开发布。
7. Wigner-like Parametrization of Canonical Seesaw Modelsid:2502.07301:id在线阅读
Shun Zhou
In this paper, we introduce the Wigner parametrization of unitary matrices and then apply it to the full description of canonical seesaw models, which extend the Standard Model with three right-handed neutrino singlets and account simultaneously for tiny Majorana neutrino masses and the baryon number asymmetry in the Universe. In the Wigner parametrization, the strong hierarchy between the electroweak scale $\Lambda^{}_{\rm EW} \approx 10^2~{\rm GeV}$ and the seesaw scale $\Lambda^{}_{\rm SS} \approx 10^{14}~{\rm GeV}$ is generally captured by three small rotation angles $\{\vartheta^{}_1, \vartheta^{}_2, \vartheta^{}_3\} \approx {\cal O}(\Lambda^{}_{\rm EW}/\Lambda^{}_{\rm SS})$, and all the remaining parameters reside in four $3\times 3$ unitary matrices. The connection between the Wigner parametrization and those in the literature is also established.
在本文中,我们介绍了单位矩阵的维格纳参数化,然后将其应用于对典范跷跷板模型的完整描述。典范跷跷板模型用三个右手中微子单子扩展了标准模型,并同时解释了宇宙中微小的马约拉纳中微子质量和重子数不对称。在维格纳参数化中,电弱尺度$\Lambda^{}_{\rm EW} 之间的强层次结构\大约 10^2~{\rm GeV}$ 和跷跷板尺度 $\Lambda^{}_{\rm SS}\通常由三個小旋轉角度捕獲 $\{vartheta^{}_1, \vartheta^{}_2, \vartheta^{}_3\\约为 {\cal O}(\Lambda^{}_{\rm EW}/\Lambda^{}_{\rm SS})$,其余所有参数都存在于四个 3 次方 3$ 的单元矩阵中。维格纳参数化与文献中的参数化之间的联系也被建立起来。
8. QCD analysis of $B \to ππ$ form factors and the $\vert V_{ub} \vert$ extraction from $B_{l4}$ decaysid:2502.07333:id在线阅读
Shan Cheng
$B_{l4}$ decays provide an independent determination of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element$\vert V_{ub} \vert$, a QCD analysis of the underlying $B \to \pi\pi$ form factors is a key ingredient to do that. We present a comprehensive QCD study of $B \to \pi\pi$ form factors from the light-cone sum rules approach by introducing two-pion light-cone distribution amplitudes ($2\pi$DAs), in which the twist three distribution amplitudes are defined and its contributions are calculated as the first time. With the partial decaying fractions of $B^+ \to \pi^+\pi^- l^+ \nu_l$ decay measured recently by Belle detector, we obtain $\vert V_{ub} \vert = \left( 3.93^{+0.45}_{-0.47}\vert_{\rm data} \pm 0.51\vert_{\rm LCSRs} \right) \times 10^{-3}$ in the predominated region of $\rho$ resonance. We clarify that the small value of $\vert V_{ub} \vert$ determined from $B \to \rho l \nu$, in comparing to the "golden" channel $B \to \pi l\nu$, is induced by the finite width and nonresonant effects. We look to the future measurements of purely isovector and isoscalar $B_{l4}$ decays which would help us to reduce the uncertainties by improving our understanding of the $\pi\pi$ phase shifts in the $2\pi$DAs via the heavy flavor decays.
$B_{l4}$ 衰变提供了对卡比波-小林-马斯喀瓦(CKM)矩阵元素$vert V_{ub}\vert$ 的独立测定。\vert$,对底层$B \to \pi\pi$形式因子的QCD分析是做到这一点的关键要素。我们通过引入双离子光锥分布振幅(2$2\pi$DAs),从光锥和规则的方法出发,对$B\to\pi\pi$形式因子进行了全面的QCD研究,其中首次定义了捻三分布振幅并计算了它的贡献。利用贝尔探测器最近测量到的$B^+ \to \pi^+\pi^- l^+ \nu_l$ 衰变的部分衰变分数,我们得到了$\vert V_{ub}\vert = \left( 3.93^{+0.45}_{-0.47}\vert_{rm data} \pm 0.51\vert_{rm LCSRs} \right) \times 10^{-3}$ in the predominated region of $\rho$ resonance.我们要澄清的是,$\vert V_{ub} 的值很小。\vert$ 是由有限宽度和非共振效应引起的。我们期待着未来对纯等矢量和等矢量$B_{l4}$衰变的测量,这将有助于我们通过重味道衰变加深对$2\pi$DAs中$\pi\pi$相移的理解,从而减少不确定性。
9. Neutralino dark matter in gauge mediationid:2502.07539:id在线阅读
Michihisa Takeuchi, Norimi Yokozaki, Junhao Zhu
We explore the potential of neutralino dark matter within the framework of gauge-mediated supersymmetry (SUSY) breaking. In our models, the lightest neutralino, as the lightest SUSY particle (LSP), is a viable dark matter candidate, assuming a gravitino mass of $\mathcal{O}(100)~\mathrm{TeV}$. The models are formulated in five-dimensional space-time, where the SUSY breaking field and the matter fields are placed on separate branes to avoid issues related to flavor and CP violation. Four distinct neutralino dark matter scenarios are studied: bino-wino coannihilation, higgsino dark matter, wino dark matter, and entropy-diluted bino dark matter. For each case, we determine the allowed parameter spaces and evaluate their consistency with existing experimental limits. Additionally, we examine the potential for testing these models through future investigations at the High-Luminosity Large Hadron Collider (HL-LHC) and through dark matter direct detection experiments.
我们在轨距介导的超对称(SUSY)破缺框架内探索了中微子暗物质的潜力。在我们的模型中,假定引力子的质量为 $\mathcal{O}(100)~\mathrm{TeV}$ ,最轻的中性子作为最轻的 SUSY 粒子(LSP),是一种可行的暗物质候选。这些模型是在五维时空中建立的,其中 SUSY 打破场和物质场被置于不同的支线上,以避免与味道和 CP 违反相关的问题。我们研究了四种不同的中微子暗物质情况:双微子共湮灭、希格斯诺暗物质、维诺暗物质和熵稀释双微子暗物质。对于每种情况,我们都确定了允许的参数空间,并评估了它们与现有实验限制的一致性。此外,我们还研究了通过高亮度大型强子对撞机(HL-LHC)的未来研究和暗物质直接探测实验来检验这些模型的潜力。
10. One-loop matching for leading-twist generalised transverse-momentum-dependent distributionsid:2502.07576:id在线阅读
Valerio Bertone, Miguel G. Echevarria, Óscar del Rio, Simone Rodini
We present the one-loop matching coefficients necessary to match all of the leading-twist generalised transverse-momentum-dependent distributions (GTMDs) onto generalised parton distributions (GPDs). Matching functions are extracted by computing the first radiative corrections to partonic bilocal correlators with staple-like Wilson lines, as appropriate for high-energy collisions. These correlators are characterised by a transverse displacement and skewed kinematics of external states. Using the proton helicity basis, they are parametrised in terms of GTMDs, which are subsequently related to leading-twist GPDs. Our results provide new insights into the complex dynamics of GTMDs generated by radiative corrections. In particular, we show that time-reversal even and odd contributions to GTMDs in the so-called ERBL region mix both under matching and evolution. Finally, we present a selection of numerical results and comment on the quantitative behaviour of GTMDs.
我们提出了将所有前旋广义横动量相关分布(GTMD)匹配到广义部分子分布(GPD)上所需的一环匹配系数。匹配函数是通过计算具有钉书针状威尔逊线的部分子双局域相关器的第一次辐射修正提取的,适合于高能对撞。这些相关器的特征是外部状态的横向位移和偏斜运动学。利用质子螺旋基,它们被参数化为 GTMD,随后又与前导扭转 GPD 相关联。我们的研究结果为了解辐射修正产生的 GTMD 的复杂动力学提供了新的视角。特别是,我们表明,在所谓的ERBL区域,时间反转对GTMD的偶数和奇数贡献在匹配和演化条件下混合在一起。最后,我们给出了部分数值结果,并对 GTMD 的定量行为进行了评论。
11. Testing spooky action between free-traveling electron-positron pairsid:2502.07597:id在线阅读
Leyun Gao, Alim Ruzi, Qite Li, Chen Zhou, Qiang Li
Quantum entanglement is a cornerstone of quantum mechanics. While the entanglement of confined electron pairs has been established early on, the entanglement of free-traveling electron pairs, particularly at high energies, remains largely unexplored due to the substantial challenges involved in measuring the spins of free-traveling electrons. In this study, we investigate the entanglement and the Bell inequality violation of free-traveling electron-positron pairs generated in a fixed-target experiment. This experimental setup facilitates the creation of a controllable source of entangled electron-positron pairs, where entangled events are produced in specific phase spaces. Based on this source and the prior knowledge of the entangled state, we demonstrate the feasibility of measuring the polarization correlations of the entangled $e^+e^-$ pairs through their individual secondary scatterings off two separate additional targets.
量子纠缠是量子力学的基石。密闭电子对的纠缠很早就被证实了,但自由旅行电子对的纠缠,尤其是在高能量下的自由旅行电子对的纠缠,由于测量自由旅行电子的自旋所涉及的巨大挑战,在很大程度上仍未被探索。在这项研究中,我们研究了在固定目标实验中产生的自由旅行电子-正电子对的纠缠和贝尔不等式违反。这种实验装置有助于创建纠缠电子-正电子对的可控源,在特定相空间中产生纠缠事件。基于这个源和对纠缠态的先验知识,我们证明了通过纠缠的 $e^+e^-$ 对在两个单独的附加靶上的二次散射来测量其偏振相关性的可行性。
12. Fock state probability changes in open quantum systemsid:2502.07673:id在线阅读
Clare Burrage, Christian Käding
Open quantum systems are powerful effective descriptions of quantum systems interacting with their environments. Studying changes of Fock states probabilities can be intricate in this context since the prevailing description of open quantum dynamics is by master equations of the systems' reduced density matrices, which usually requires finding solutions for a set of complicated coupled differential equations. In this article, we show that such problems can be circumvented by employing a recently developed path integral-based method for directly computing reduced density matrices in scalar quantum field theory. For this purpose, we consider a real scalar field $\phi$ as an open system interacting via a $\lambda \chi^2\phi^2$-term with an environment comprising another real scalar field $\chi$ that has a finite temperature. In particular, we investigate how the probabilities for observing the vacuum or two-particle states change over time if there were initial correlations of these Fock states. Subsequently, we apply our resulting expressions to a neutrino toy model. We show that, within our model, lighter neutrino masses would lead to a stronger distortion of the observable number of particles due to the interaction with the environment after the initial production process.
开放量子系统是量子系统与其环境相互作用的强大有效描述。在这种情况下,研究福克态概率的变化可能是错综复杂的,因为对开放量子动力学的普遍描述是通过系统的还原密度矩阵的主方程来实现的,这通常需要找到一组复杂的耦合微分方程的解。在这篇文章中,我们展示了在标量量子场论中采用最近开发的基于路径积分的方法直接计算还原密度矩阵可以规避这些问题。为此,我们将一个实标量场$\phi$视为一个开放系统,它通过一个$\lambda \chi^2\phi^2$ 项与由另一个实标量场$\chi$组成的、具有有限温度的环境相互作用。我们特别研究了如果这些福克态存在初始相关性,那么观测真空态或双粒子态的概率是如何随时间变化的。随后,我们将得出的表达式应用于中微子玩具模型。我们表明,在我们的模型中,较轻的中微子质量会导致可观测到的粒子数量因初始产生过程后与环境的相互作用而发生更大的扭曲。
13. Searching for Inflationary Physics with the CMB Trispectrum: 3. Constraints from Planckid:2502.06931:id在线阅读
Oliver H. E. Philcox
Is there new physics hidden in the four-point function of the cosmic microwave background (CMB)? We conduct a detailed analysis of the Planck PR4 temperature and polarization trispectrum for $\ell\in[2,2048]$. Using the theoretical and computational tools developed in Paper 1 and Paper 2, we search for 33 template amplitudes, encoding a variety of effects from inflationary self-interactions to particle exchange. We find no evidence for primordial non-Gaussianity and set stringent constraints on both phenomenological amplitudes and couplings in the inflationary Lagrangian. Due to the use of optimal estimators and polarization data, our constraints are highly competitive. For example, we find $\sigma(g_{\rm NL}^{\rm loc})=4.8\times 10^4$ and $\tau_{\rm NL}^{\rm loc} <1500$ (95\% CL), a factor of two improvement on Effective Field Theory amplitudes, and a $43\sigma$ detection of gravitational lensing. Many templates are analyzed for the first time, such as direction-dependent trispectra and the collapsed limit of the `cosmological collider', across a range of masses and spins. We perform a variety of validation tests; whilst our results are stable, the most relevant systematics are found to be lensing bias, residual foregrounds, and mismatch between simulations and data. The techniques discussed in this series can be extended to future datasets, allowing the primordial Universe to be probed at even higher sensitivity.
宇宙微波背景(CMB)的四点函数中是否隐藏着新物理学?我们对普朗克 PR4 温度和偏振三谱进行了详细分析。利用论文1和论文2中开发的理论和计算工具,我们搜索了33个模板振幅,它们编码了从暴胀自相互作用到粒子交换的各种效应。我们没有发现原始非高斯性的证据,并对膨胀拉格朗日中的现象振幅和耦合都设置了严格的约束。由于使用了最优估计和极化数据,我们的约束具有很强的竞争力。例如,我们发现了$\sigma(g_{/rm NL}^{\rm loc})=4.8\times 10^4$和$\tau_{/rm NL}^{\rm loc} <1500$(95/% CL),这是对有效场论振幅的两倍改进,并且发现了引力透镜的$43\sigma$。我们首次分析了许多模板,如与方向相关的三谱和 "宇宙对撞机 "的坍缩极限,以及一系列质量和自旋。我们进行了各种验证测试;虽然我们的结果是稳定的,但发现最相关的系统性是透镜偏差、残余前景以及模拟和数据之间的不匹配。本系列讨论的技术可以扩展到未来的数据集,从而以更高的灵敏度探测原始宇宙。
14. Gradient Flows and the Curvature of Theory Spaceid:2502.06940:id在线阅读
William H. Pannell, Andreas Stergiou
The metric and potential associated with the gradient property of renormalisation group flow in multiscalar models in $d=4-\varepsilon$ dimensions are studied. The metric is identified with the Zamolodchikov metric of nearly marginal operators on the sphere. An explicit form for the associated Ricci scalar in $d=4-\varepsilon$ is derived, which shows that the space of multiscalar field theories is curved. The potential is identified with a quantity $\widetilde{F}$ that was previously proposed as a weakly monotonic function interpolating between the $a$-theorem in four dimensions and the $F$-theorem in three dimensions. This implies that the $\widetilde{F}$-theorem can be extended perturbatively to a theorem about gradient flow in $d=4-\varepsilon$.
研究了在$d=4-\varepsilon$维度的多元帅模型中与重正化群流的梯度特性相关的度量和势。该度量与球面上近边际算子的扎莫洛奇科夫度量相一致。推导出了$d=4-\varepsilon$维相关里奇标量的明确形式,这表明多斯卡尔场论的空间是弯曲的。该势能与$\widetilde{F}$量相一致,而$\widetilde{F}$量是之前提出的介于四维中的$a$定理和三维中的$F$定理之间的弱单调函数。这意味着$\widetilde{F}$定理可以微扰地扩展为关于$d=4-\varepsilon$中梯度流的定理。
15. QED nuclear medium effects at EIC energiesid:2502.06943:id在线阅读
Shohini Bhattacharya, Oleksandr Tomalak, Ivan Vitev
We present the first calculation of quantum electrodynamics (QED) nuclear medium effects under the experimental conditions of future Electron-Ion Collider (EIC) experiments. Our work offers numerical estimates, particularly in the context of inclusive deep inelastic scattering on a $^{208}_{82}\mathrm{Pb}$ nucleus. While prior studies have predominantly focused on elastic scattering, our investigation extends to the more complex scenarios of inelastic processes within a nuclear medium. Our findings suggest that the cross-section corrections due to QED nuclear medium effects could be substantial, reaching or exceeding the level of experimental precision. This work further compares the effects of single re-scattering events with those of multiple re-scatterings, as particles travel the nuclear volume. We estimate the dominant source of the uncertainties associated with our formalism by varying the scale of the atomic physics where the screening of the electric field of the nucleus happens. This calculation not only contributes to the understanding of QED nuclear medium effects, but also offers a path to a more precise extraction of the process-independent non-perturbative structure of nuclei.
我们首次提出了在未来电子-离子对撞机(EIC)实验条件下对量子电动力学(QED)核介质效应的计算。我们的工作提供了数值估计,特别是在$^{208}_{82}\mathrm{Pb}$原子核的包容性深非弹性散射的背景下。之前的研究主要集中于弹性散射,而我们的研究则扩展到了核介质中更复杂的非弹性过程。我们的研究结果表明,由 QED 核介质效应引起的截面修正可能很大,达到或超过实验精度水平。这项工作进一步比较了单次再散射事件和多次再散射事件的影响,因为粒子在核体积中移动。我们通过改变原子核电场屏蔽发生的原子物理学尺度,来估计与我们的形式主义相关的不确定性的主要来源。这一计算不仅有助于理解 QED 核介质效应,而且为更精确地提取与过程无关的原子核非微扰结构提供了途径。
16. Comprehensive Analysis of Thermal Dissipation in Lithium-Ion Battery Packsid:2502.07070:id在线阅读
Xuguang Zhang, Hexiang Zhang, Amjad Almansour, Mrityunjay Singh, Hengling Zhu, Michael C. Halbig, Yi Zheng
Effective thermal management is critical for lithium-ion battery packs' safe and efficient operations, particularly in applications such as drones, where compact designs and varying airflow conditions present unique challenges. This study investigates the thermal performance of a 16-cell lithium-ion battery pack by optimizing cooling airflow configurations and integrating phase change materials (PCMs) for enhanced heat dissipation. Seven geometric configurations were evaluated under airflow speeds ranging from 0 to 15 m/s, reflecting the operational conditions of civilian drones. A comprehensive 3D simulation approach was used to analyze the effects of inlet and outlet configurations, airflow dynamics, and PCM phase transition behavior. Results indicate that the trapezoidal (wide-base) configuration, paired with a 5-inlet and 1-outlet setup, achieves the most balanced performance, effectively maintaining optimal operating temperatures across low and high-speed airflow conditions. PCM integration further stabilized thermal behavior, with phase change durations extending to 12.5 min under tested conditions. These findings highlight the importance of geometric optimization and material integration in advancing compact and reliable thermal management systems for energy-dense battery packs. This study provides a foundation for designing efficient cooling strategies tailored to lightweight applications such as drones and portable energy storage systems.
有效的热管理对于锂离子电池组的安全高效运行至关重要,尤其是在无人机等应用中,紧凑的设计和多变的气流条件带来了独特的挑战。本研究通过优化冷却气流配置和集成相变材料 (PCM) 以增强散热,对 16 芯锂离子电池组的热性能进行了研究。在气流速度为 0 至 15 米/秒(反映了民用无人机的运行条件)的条件下,对七种几何配置进行了评估。采用综合三维模拟方法分析了入口和出口配置、气流动力学和 PCM 相变行为的影响。结果表明,梯形(宽底座)配置与 5 进风口和 1 出风口设置的搭配实现了最均衡的性能,可在低速和高速气流条件下有效保持最佳工作温度。PCM 集成进一步稳定了热性能,在测试条件下,相变持续时间延长至 12.5 分钟。这些发现凸显了几何优化和材料集成在为能量密集型电池组推进紧凑可靠的热管理系统方面的重要性。这项研究为设计适合无人机和便携式储能系统等轻型应用的高效冷却策略奠定了基础。
17. QCD Anderson transition with overlap valence quarks on a twisted-mass sea -- an updateid:2502.07434:id在线阅读
Robin Kehr, Lorenz von Smekal
We investigate the QCD Anderson transition by studying the low-lying eigenmodes of the overlap operator in the background of gauge configurations with 2+1+1 quark flavors of twisted-mass Wilson fermions. The mobility edge, below which eigenmodes are localized, is estimated by the inflection point of the relative volume. The analysis of its temperature dependence suggests a close relation of localization to chiral symmetry restoration. We update our previous work [1] by including recent results on lower temperatures and switching to improved estimates of the lattice spacing and pseudocritical temperature respectively pion mass. Contrary to the previous prediction, our the mobility edge estimate does not vanish at the temperature of the chiral phase transition. We discuss a possible scenario, supported by literature, for why this could be the case.
我们通过研究在具有 2+1+1 夸克味的扭转质量威尔逊费米子的规规构型背景下重叠算子的低洼特征模来研究 QCD 安德森转变。通过相对体积的拐点估算出特征模局部化的流动边缘。对其温度依赖性的分析表明,局域化与手性对称性恢复密切相关。我们更新了之前的工作[1],纳入了最近在更低温度下的研究成果,并转而改进了对晶格间距和先驱质量伪临界温度的估算。与之前的预测相反,我们的流动边缘估计值在手性相变温度下并没有消失。我们讨论了为什么会出现这种情况的一种可能情况,并得到了文献的支持。
[1] R. Kehr, D. Smith and L. von Smekal, QCD Anderson transition with overlap valence quarks on a twisted-mass sea, Phys. Rev. D 109 (2024) 074512 [2304.13617].
18. Modified theories of gravity at different curvature scalesid:2502.07437:id在线阅读
Susobhan Mandal, S. Shankaranarayanan (IIT Bombay)
General Relativity (GR) remains the cornerstone of gravitational physics, providing remarkable success in describing a wide range of astrophysical and cosmological phenomena. However, several challenges underscore the urgent need to explore modified gravity theories. GR struggles to reconcile with quantum mechanics, fails to provide fundamental explanations for dark matter and dark energy, and faces limitations in describing extreme regimes such as black hole singularities and the very early universe. This review provides an organized perspective on modified gravity theories by classifying them based on the principles of GR they preserve or violate. Specifically, we consider three broad categories: (1) metric theories that uphold local Lorentz invariance (LLI) and gauge invariance, (2) theories that break gauge invariance, LLI, or parity, and (3) beyond-metric theories that violate the Einstein's equivalence principle (EEP). This classification highlights the underlying assumptions of GR that these theories challenge or extend, providing a framework for understanding their motivations and implications. The review also discusses the current and upcoming experimental and observational tests of GR, including those probing its foundational principles, such as LLI, gauge invariance, and EEP. For each class of modified theories, we examine their ability to address critical open questions in cosmology and black hole physics. These include their potential to explain the accelerated expansion of the current universe, the nature of dark matter, and deviations in black hole dynamics from GR predictions. This review aims to provide a structured understanding of modified gravity theories and their observational implications in the multimessenger era by focusing on the principles preserved or violated. [abridged]
广义相对论(GR)仍然是引力物理学的基石,在描述广泛的天体物理和宇宙学现象方面取得了巨大成功。然而,一些挑战凸显了探索修正引力理论的迫切性。引力理论难以与量子力学相协调,无法为暗物质和暗能量提供基本解释,在描述黑洞奇点和极早期宇宙等极端状态时也面临局限。本综述根据修正引力理论所保留或违反的 GR 原则对其进行分类,从而为修正引力理论提供了一个有条理的视角。具体来说,我们考虑了三大类:(1)坚持局部洛伦兹不变性(LLI)和规规不变性的度量理论;(2)打破规规不变性、LLI 或奇偶性的理论;(3)违反爱因斯坦等效原理(EEP)的超越度量理论。这种分类强调了这些理论挑战或扩展的 GR 的基本假设,为理解它们的动机和影响提供了一个框架。综述还讨论了当前和即将对全球定位系统进行的实验和观测检验,包括探究其基本原理的检验,如 LLI、量规不变性和等效原理。对于每一类修正理论,我们都考察了它们解决宇宙学和黑洞物理学中关键开放问题的能力。这些问题包括它们解释当前宇宙加速膨胀的潜力、暗物质的性质以及黑洞动力学与 GR 预测的偏差。这篇综述旨在通过重点讨论所保留或违反的原则,提供对修正引力理论及其在多信使时代的观测影响的结构性理解。[有删节]
19. Low-energy $DD$ scattering in lattice QCDid:2502.07438:id在线阅读
Pan-Pan Shi, Feng-Kun Guo, Chuan Liu, Liuming Liu, Peng Sun, Jia-Jun Wu, Hanyang Xing
We present the first lattice QCD calculation of single-channel $DD$ scattering with quantum numbers $I(J^P)=1(0^+)$ and $0(1^-)$. The calculation is performed on the $2+1$ flavor Wilson-Clover ensembles with a lattice spacing $a\simeq 0.077$ fm and two different pion masses, $m_{\pi}\simeq207$ and $305$ MeV. The scattering parameters are determined using the Lüscher's finite volume method. Our results indicate weak repulsive interaction in the $1(0^+)$ channel and slightly attractive interaction in the $0(1^-)$ channel. The $S$-wave isovector $DD$ scattering length and effective range, extrapolated to the physical pion mass, are $(-0.26\pm0.05)$ fm and $(-5.5\pm2.1)$ fm, respectively.
我们首次提出了量子数为$I(J^P)=1(0^+)$和$0(1^-)$的单通道$DD$散射的晶格QCD计算。计算是在晶格间距为$a\simeq 0.077$ fm、先锋质量为$m_{pi}\simeq207$和$305$ MeV的2+1$味威尔逊-克洛弗集合上进行的。散射参数是用 Lüscher's 有限体积法确定的。我们的结果表明,在$1(0^+)$通道中存在微弱的排斥作用,而在$0(1^-)$通道中存在轻微的吸引作用。推断到物理先驱质量的$S$波等矢量$DD$散射长度和有效范围分别是$(-0.26\pm0.05)$ fm和$(-5.5\pm2.1)$ fm。
20. Detectability of dark matter subhalo impacts in Milky Way stellar streamsid:2502.07781:id在线阅读
Junyang Lu, Tongyan Lin, Mukul Sholapurkar, Ana Bonaca
Stellar streams are a promising way to probe the gravitational effects of low-mass dark matter (DM) subhalos. In recent years, there has been a remarkable explosion in the number of stellar streams detected in the Milky Way, and hundreds more may be discovered with future surveys such as LSST. Studies of DM subhalo impacts on streams have so far focused on a few of the thinnest and brightest streams, and it is not known how much information can be gained from the others. In this work, we develop a method to quickly estimate the minimum detectable DM subhalo mass of a given stream, where subhalo mass here refers to the total mass of a Plummer sphere. Our work is based on an analytic model for subhalo impacts on circular streams, which allows us to model streams with a wide range of properties including width, length, distance, and stellar density. We consider several observational scenarios, based on current and future surveys including Gaia, DESI, Via, and LSST. We find that at 95% confidence level, a stream like GD-1 has a minimum detectable subhalo mass of $\sim 6\times 10^6~\mathrm{M}_{\odot}$ in Gaia data and $\sim 8\times 10^5~\mathrm{M}_{\odot}$ with LSST 10 year sensitivity. Applying our results to confirmed Milky Way streams, we rank order them by their sensitivity to DM subhalos and identify promising ones for further study.
恒星流是探测低质量暗物质(DM)亚halos 引力效应的一种很有前途的方法。近年来,银河系中探测到的恒星流数量激增,未来的巡天观测(如 LSST)可能还会发现数以百计的恒星流。迄今为止,关于 DM 亚halo 对恒星流的影响的研究主要集中在少数最薄、最亮的恒星流上,其他恒星流能提供多少信息尚不得而知。在这项工作中,我们开发了一种方法来快速估算给定星流的最小可探测到的 DM 亚halo 质量,这里的亚halo 质量指的是 Plummer 球体的总质量。我们的工作基于子晕撞击环流的分析模型,该模型允许我们对具有各种属性(包括宽度、长度、距离和恒星密度)的环流进行建模。我们考虑了几种基于当前和未来巡天的观测方案,包括盖亚、DESI、Via 和 LSST。我们发现,在95%的置信度下,像GD-1这样的星流在Gaia数据中最小可探测到的亚halo质量为$\sim 6\times 10^6~\mathrm{M}_{\odot}$,在LSST 10年灵敏度下最小可探测到的亚halo质量为$\sim 8\times 10^5~\mathrm{M}_{\odot}$。将我们的结果应用于已确认的银河流,我们按照它们对DM亚halos的灵敏度对它们进行了排序,并确定了有希望进一步研究的银河流。
21. Neutron structure function via a maximum entropy analysisid:1801.01387:id在线阅读
Chengdong Han, Rong Wang, Xurong Chen
We employ the maximum entropy method to extract the valence quark distributions of the neutron at a low scale, \( Q_0^2 \). At this initial scale, the neutron is defined to contain only three valence quarks, with no contributions from sea quarks or gluons. The distributions of these initial valence quarks are constrained by principles from quark models, quark-hadron duality, and quark confinement. Employing the DGLAP equations supplemented by parton-parton recombination corrections, we derive the neutron structure function \( F_2^{\rm n} \) at higher scales \( Q^2 \). The resulting ratio of the neutron to proton structure functions, \( F_2^{\rm n}/F_{2}^{\rm p} \), aligns well with world data from deep inelastic scattering (DIS) on proton and deuteron targets, particularly when accounting for uncertainties from model-dependent corrections. Notably, this ratio is in agreement with the JLab MARATHON dataset, especially as \( x \) approaches 1. Additionally, our findings for \( F_2^{\rm n}/F_{2}^{\rm p} \) correspond well with the JLab BONuS experimental results after considering the impact of nucleon resonance contamination in the region \( x \gtrsim 0.4, 0.5, 0.6 \). We further compare our predictions for \( F_2^{\rm n}/F_{2}^{\rm p} \) and the \( u/d \) ratios in the limit as \( x \rightarrow 1 \) with existing theoretical calculations. Finally, we observe a minor violation of isospin symmetry between the proton and neutron, evidenced by the differences in valence quark distributions and the first-order moments of these distributions.
我们采用最大熵方法来提取中子在低尺度(\( Q_0^2 \))下的价夸克分布。在这个初始尺度上,中子被定义为只包含三个价夸克,没有海夸克或胶子的贡献。这些初始价夸克的分布受制于夸克模型、夸克-中子对偶性和夸克约束等原理。利用DGLAP方程并辅以部分子-部分子重组修正,我们得出了中子结构函数(F_2^{\rm} n)在更高尺度上的(Q^2)。由此得出的中子与质子结构函数之比(F_2^{\rm n}/F_{2}^{\rm p} )与质子和氘核目标上的深非弹性散射(DIS)的世界数据非常吻合,尤其是在考虑到模型修正带来的不确定性时。值得注意的是,这一比率与 JLab MARATHON 数据集一致,特别是当\( x \)接近 1 时。此外,在考虑了核子共振污染对 \( x \gtrsim 0.4, 0.5, 0.6 \)区域的影响之后,我们对 \( F_2^{\rm n}/F_{2}^{\rm p} \)的预测结果与JLab BONuS的实验结果非常吻合。我们进一步将我们对F_2^{rm n}/F_{2}^{rm p} 和u/d 的预测结果与现有的理论计算结果进行了比较。最后,我们观察到质子和中子之间存在轻微的违反等空对称性的现象,这可以从价夸克分布和这些分布的一阶矩的差异中得到证明。
22. Polarization Signals from Axion-Photon Resonant Conversion in Neutron Star Magnetosphereid:2402.15144:id在线阅读
Ningqiang Song, Liangliang Su, Lei Wu
Neutron stars provide ideal astrophysical laboratories for probing new physics beyond the Standard Model. If axions exist, photons can develop linear polarization during photon-axion conversion in the magnetic field of a neutron star. We find that the plasma in the neutron star magnetosphere could dramatically enhance the polarization through the resonant conversion effect. With the polarization measurements from PSR B0656+14, 4U 0142+61, and the benchmark polarization measurement in the mid-infrared band, we demonstrate that optical and infrared polarization from neutron stars can provide strong constraints on the axion-photon coupling over a broad axion mass range $10^{-11}\lesssim m_a \lesssim 10^{-3}$ eV.
中子星为探测标准模型之外的新物理学提供了理想的天体物理实验室。如果轴子存在,光子在中子星磁场中进行光子-轴子转换时就会产生线性极化。我们发现,中子星磁层中的等离子体可以通过共振转换效应显著增强极化。通过对PSR B0656+14、4U 0142+61的偏振测量,以及在中红外波段的基准偏振测量,我们证明了中子星的光学和红外偏振可以在很宽的轴子质量范围$10^{-11}\lesssim m_a \lesssim 10^{-3}$ eV内对轴子-光子耦合提供强有力的约束。
23. Wide Binary Evaporation by Dark Solitons: Implications from the GAIA Catalogid:2404.18099:id在线阅读
Qiming Qiu, Yu Gao, Haijun Tian, Kechen Wang, Zihang Wang, Xiangming Yang
An analytic calculation is given for binary star evaporation under the tidal perturbation from randomly distributed, spatially extended dark objects. In particular, the Milky Way's wide binary star population is susceptible to such disruption from dark matter solitons of comparable and larger sizes. We identify high-probability `halo-like' wide binaries in GAIA EDR3 with separations larger than 0.1 parsec. Survival of the farthest-separated candidates will provide a novel gravitational probe to dark matter in the form of solitons. In the case of dilute axion-like boson stars, the observational sensitivity extends into the axion mass range $m_a \sim 10^{-17}-10^{-15}$ eV.
在随机分布、空间延伸的暗物质潮汐扰动下,给出了双星蒸发的解析计算。特别是,银河系的宽双星群很容易受到大小相当或更大的暗物质孤子的干扰。我们在GAIA EDR3中发现了高概率的 "类河马';宽双星",它们之间的距离大于0.1皮秒。距离最远的候选者的存活将以孤子的形式为暗物质提供一个新的引力探测器。在稀释轴子样玻色子星的情况下,观测灵敏度会扩展到轴子质量范围$m_a \sim 10^{-17}-10^{-15}$ eV。
24. A quantitative analysis of Gravitational Wave spectrum sourced from First-Order Chiral Phase Transition of QCDid:2407.03795:id在线阅读
Hui-wen Zheng, Fei Gao, Ligong Bian, Si-xue Qin, Yu-xin Liu
We investigate the cosmological first-order chiral phase transition of QCD, and for the first time calculate its parameters which can fully determine the gravitational wave spectrum. With the state-of-the-art calculation from the functional QCD method, we found that the large chemical potential of QCD phase transition results in very weak and fast first-order phase transitions at the temperature lower than $\mathcal{O}(10^2)$ MeV. These results further suggest that the GW signals of NANOGrav are very unlikely sourced from the chiral phase transition of QCD.
我们研究了QCD的宇宙学一阶手性相变,并首次计算了其参数,从而可以完全确定引力波谱。通过最先进的函数QCD方法计算,我们发现QCD相变的大化学势导致在温度低于$mathcal{O}(10^2)$ MeV时的一阶相变非常微弱和快速。这些结果进一步表明,NANOGrav 的 GW 信号不太可能来自 QCD 的手性相变。
25. Reduced cross section and gluon distribution in a momentum-space approachid:2408.02254:id在线阅读
G.R.Boroun, Phuoc Ha
We present a calculation of the reduced cross section in momentum-space approach utilizing the Block-Durand-Ha (BDH) parameterization of the proton structure function $F_{2}(x,Q^2)$ and the leading-order (LO) longitudinal structure function $F_{L}(x,Q^2)$, proposed by Boroun and Ha [G.R. Boroun and this http URL, Phys. Rev. D {\bf 109} (2024) 094037] using Laplace transform techniques. Our results are compared with the HERA data and extended to the Large Hadron electron Collider (LHeC) domain. We also examine the ratio $F_{L2}(x, Q^2)=F_{L}(x, Q^2)/F_{2}(x, Q^2)$ obtained from our work, comparing it with both the H1 data and the color dipole (CDP) bounds. We find that our results for the reduced cross section and the ratio $F_{L2}(x, Q^2)$ agree with the H1 data. Finally, our evaluation of the gluon distribution functions $G(x,Q^2)$ in momentum-space approach shows very good concordance with the NNPDF3.0LO gluon structure functions for moderate $Q^2$ in the range $10^{-5}{\leq}x{\leq}1$.
我们介绍了利用质子结构函数 $F_{2}(x,Q^2)$ 的 Block-Durand-Ha (BDH) 参数化以及 Boroun 和 Ha [G. R. Boroun and this[URL]提出的前导阶 (LO) 纵向结构函数 $F_{L}(x,Q^2)$ 在动量空间方法中计算减少的截面。R. Boroun and this http URL, Phys.(2024) 094037]。我们的结果与 HERA 数据进行了比较,并扩展到了大型强子对撞机(LHeC)领域。我们还检验了从我们的工作中得到的比值 $F_{L2}(x,Q^2)=F_{L}(x,Q^2)/F_{2}(x,Q^2)$,并将其与 H1 数据和彩色偶极子(CDP)边界进行了比较。我们发现,我们的缩小截面和比值 $F_{L2}(x, Q^2)$ 与 H1 数据一致。最后,在动量空间方法中,我们对胶子分布函数$G(x,Q^2)$的评估显示,在$10^{-5}{\leq}x{leq}1$范围内,对于中等的$Q^2$,我们的结果与NNPDF3.0LO胶子结构函数非常一致。
26. A Simple Parametrisation of the Pion Form Factorid:2410.13764:id在线阅读
Matthew Kirk, Bastian Kubis, Méril Reboud, Danny van Dyk
We discuss a novel and simple parametrisation of the pion vector form factor that transparently connects spacelike and timelike regions of the momentum transfer $q^2$. Our parametrisation employs the framework of conformal mapping and respects the known analyticity properties of the form factor, accounting explicitly for the $\rho(770)$-meson pole. The parametrisation manifestly fulfils the normalisation condition at $q^2 = 0$ as well as further restrictions at the pion production threshold and in the limit $|q^2| \to \infty$. In contrast to the widely used Omnès parametrisation, our approach does not use the pion-pion scattering phase shift as input. We confront the parametrisation with experimental data from $\pi H$ scattering and $\tau^- \to \pi^-\pi^0\nu$ decay. We already find a good description of the data with only five free parameters, which include the pole mass and decay width of the $\rho(770)$.
我们讨论了先驱矢量形式因子的一种新颖而简单的参数化,它透明地连接了动量传递 $q^2$ 的空间和时间区域。我们的参数化采用了共形映射的框架,并尊重形式因子的已知解析特性,明确地考虑到了\rho(770)$介子极。参数化显然满足了在$q^2 = 0$时的归一化条件,以及在先驱产生阈值和极限$|q^2| \to \infty$时的进一步限制。与广泛使用的奥姆尼斯参数化不同,我们的方法不使用先驱-离子散射相移作为输入。我们用$\pi H$ 散射和$\tau^- \to \pi^-\pi^0\nu$衰变的实验数据来检验参数化。我们发现仅用五个自由参数就能很好地描述这些数据,其中包括极点质量和 $\rho(770)$ 衰变宽度。
27. Right-handed interactions in puzzling $B$-decaysid:2410.23257:id在线阅读
Damir Bečirević, Svjetlana Fajfer, Nejc Košnik, Lovre Pavičić
We explain the difference between the measured decay widths of $b \to c \tau \nu$ processes and of $B\to K\nu\bar{\nu}$ and their values predicted in the Standard Model by introducing the right-handed interactions both to quarks and to leptons. At low energy scales, in addition to the Standard Model particles, we assume the presence of an additional neutral lepton (right-handed neutrino). We then show a specific realization of such a scenario in a model with a single scalar leptoquark ($S_1$), and discuss the corresponding phenomenology.
我们通过引入夸克和轻子的右手相互作用来解释$b \to c \tau \nu$过程和$B\to K\nu\bar{\nu}$ 过程的测量衰变宽度与标准模型预测值之间的差异。在低能量尺度下,除了标准模型粒子,我们还假设存在一个额外的中性轻子(右手中微子)。然后,我们展示了这种情况在单标量轻夸克($S_1$)模型中的具体实现,并讨论了相应的现象学。
28. Imprints of Early Universe Cosmology on Gravitational Wavesid:2411.09757:id在线阅读
James B. Dent, Bhaskar Dutta, Mudit Rai
We explore the potential of gravitational waves (GWs) to probe the pre-BBN era of the early universe, focusing on the effects of energy injection. Specifically, we examine a hidden sector alongside the Standard Model that undergoes a strong first-order phase transition (FOPT), producing a GW signal. Once the phase transition has completed, energy injection initiates reheating in the hidden sector, which positions the hidden sector field so that additional phase transitions can occur. This can result in a total of three distinct phase transitions with a unique three-peak GW spectrum. Among these transitions, the first and third are of the standard type, while the intermediate second transition is inverted, moving from a broken to an unbroken phase. Using polynomial potentials as a framework, we derive analytical relations among the phase transition parameters and the resulting GW spectrum. Our results indicate that the second and third transitions generate GWs with higher amplitudes than the first, with a peak frequency ratio differing by up to an order of magnitude. This three-peak GW spectrum is detectable by upcoming facilities such as LISA, BBO, and UDECIGO. Notably, the phenomenon is robust across various potentials and model parameters, suggesting that hidden sector GWs provide a powerful tool for exploring new physics scenarios in the pre-BBN era.
我们探索了引力波(GWs)探测早期宇宙前BN时代的潜力,重点是能量注入的影响。具体地说,我们研究了标准模型旁边的一个隐藏扇区,它经历了一个强一阶相变(FOPT),产生了一个引力波信号。一旦相变完成,能量注入会启动隐藏扇区的再加热,从而定位隐藏扇区场,以便发生更多相变。这可能导致总共三次不同的相变,并产生独特的三峰 GW 频谱。在这些转变中,第一个和第三个转变属于标准类型,而中间的第二个转变则是反相的,从断裂相转变为未断裂相。我们以多项式势为框架,推导出了相变参数和由此产生的 GW 频谱之间的分析关系。我们的研究结果表明,第二和第三次转变产生的全球瓦振幅高于第一次转变,峰值频率比最高相差一个数量级。即将投入使用的设施,如 LISA、BBO 和 UDECIGO,都能探测到这种三峰值 GW 频谱。值得注意的是,这一现象在不同的电势和模型参数下都是稳健的,这表明隐藏扇区全球瓦为探索前宽带天体时代的新物理情景提供了一个强大的工具。
29. Unveiling E$_6$SSM Scalar Diquarks at the HL-LHCid:2412.19445:id在线阅读
Murad Ali, Shaaban Khalil, Stefano Moretti, Shoaib Munir, Harri Waltari
We investigate the phenomenology of scalar diquarks with sub-TeV masses within the framework of the $E_6$ Supersymmetric Standard Model (E$_6$SSM) at the Large Hadron Collider (LHC). Focusing on the lightest of the six diquarks predicted by the model, we select some representative low masses for them in a parameter space region consistent with experimental constraints from direct searches for additional Higgs boson(s), Cold Dark Matter (CDM), and supersymmetry, as well as from flavor physics analyses. Using Monte Carlo ($MC$) simulations, we assess these benchmark points against the latest LHC results corresponding to an integrated luminosity of 140 fb$^{-1}$. We further evaluate the signal significance of the pair-production of these diquarks, when each of them decays into $tb$ pairs, at the $\sqrt{s}=13$ TeV LHC Run 3 with design integrated luminosity of 300 fb$^{-1}$, and also at the 3000 fb$^{-1}$ High-Luminosity LHC (HL-LHC). Our analysis yields a statistical significance exceeding $3\sigma$ at the HL-LHC for diquark masses up to 1 TeV, indicating promising prospects for their discovery.
我们在大型强子对撞机(LHC)的$E_6$超对称标准模型(E$_6$SSM)框架内研究了质量在TeV以下的标量二夸克现象学。我们以该模型预测的六种二夸克中最轻的一种为重点,在参数空间区域内为它们选择了一些有代表性的低质量,这些低质量与直接搜索额外的希格斯玻色子、冷暗物质(CDM)和超对称性以及味道物理分析所产生的实验约束相一致。通过蒙特卡罗($MC$)模拟,我们根据大型强子对撞机的最新结果评估了这些基准点,其综合光度为140 fb$^{-1}$。我们进一步评估了这些二夸克在$\sqrt{s}=13$ TeV大型强子对撞机运行3(设计综合光度为300 fb$^{-1}$)以及3000 fb$^{-1}$高亮度大型强子对撞机(HL-LHC)上各自衰变成$tb$对产生的信号意义。我们的分析结果表明,在HL-LHC上,对于质量高达1 TeV的二夸克,统计意义超过了$3\sigma$,这表明发现它们的前景十分广阔。
30. Strangeness in the proton from W+charm production and SIDIS dataid:2501.00665:id在线阅读
Trey Anderson, W. Melnitchouk, N. Sato
We perform a global QCD analysis of unpolarized parton distribution functions (PDFs) in the proton, including new $W$+charm production data from $pp$ collisions at the LHC, which have been suggested for constraining the strange quark PDF. In particular, we assess the impact of the $W$+charm data relative to that of semi-inclusive pion and kaon production data in lepton-nucleon deep-inelastic scattering. Compared with a baseline global fit that does not include these datasets, we find that semi-inclusive deep-inelastic scattering and $W$+charm data combined favor a larger strange distribution, but smaller than the SU(3) symmetric sea suggested in some previous analyses. Combined, the ratio of strange to nonstrange sea quark distributions is $R_s = (s+\bar s)/(\bar u+\bar d) \approx \{ 0.69,\, 0.49,\, 0.29 \}$ for $x = \{ 0.01,\, 0.04,\, 0.1 \}$.
我们对质子中的非极化粒子分布函数(PDF)进行了全局性的 QCD 分析,包括来自大型强子对撞机 $pp$ 碰撞的新 $W$+charm 产生数据,这些数据被建议用于约束奇异夸克 PDF。我们特别评估了 W$+charm 数据与轻子-核子深弹性散射中半包先驱和高子产生数据的影响。与不包括这些数据集的基线全局拟合相比,我们发现半包深弹性散射和$W$+charm数据加在一起有利于更大的奇异分布,但小于之前一些分析中提出的SU(3)对称海。结合起来看,奇异海与非奇异海夸克分布之比为 $R_s = (s+\bar s)/(\bar u+\bar d) \approx \{ 0.69,\, 0.49,\, 0.29 \}$ for $x = \{ 0.01,\, 0.04,\, 0.1 \}$。
31. Bayesian Inferring Nucleon's Gravitation Form Factors via Near-threshold $J/ψ$ Photoproductionid:2501.10532:id在线阅读
Yuxun Guo, Feng Yuan, Wenbin Zhao
With Bayesian inference, we investigate the impact of recent near-threshold $J/\psi$ production measurements by the $J/\psi$ 007 experiment and GlueX collaboration on the extraction of proton's gravitational form factors. We apply the generalized parton distribution framework at the next-to-leading order and demonstrate a stable expansion for the near-threshold kinematics. We find that the experimental constraints are in good agreement with the state-of-the-art lattice simulations, where negative $C_q(t)$ and $C_g(t)$ are strongly preferred. This highlights a great potential to extract them from future high-precision experiments.
通过贝叶斯推理,我们研究了$J/\psi$ 007实验和GlueX合作最近的近阈值$J/\psi$产生测量对质子引力形式因子提取的影响。我们在次先导阶应用了广义粒子分布框架,并证明了近阈值运动学的稳定扩展。我们发现,实验约束与最先进的晶格模拟非常一致,其中负的 $C_q(t)$ 和 $C_g(t)$ 更受青睐。这凸显了从未来高精度实验中提取它们的巨大潜力。
32. Local form factor subtraction for three-loop QCD corrections to electroweak production in quark-antiquark annihilationid:2502.00572:id在线阅读
Rayan Haindl
We extend a local subtraction framework to three-loop QCD corrections for the production of multiple electroweak bosons in quark-antiquark annihilation. We derive two-loop Ward identities that ensure the factorisation of most collinear singularities from the hard-scattering process in the sum over integrands. Infrared and ultraviolet singularities are removed point-by-point in loop momentum space using a minimal set of counterterms, which can be integrated analytically in terms of known master integrals. Additional counterterms eliminate non-factorising terms arising from loop momentum shifts and one-loop corrections to the gluon three-point function. We identify previously unknown non-factorising loop polarisation effects in the single-collinear regions, which pose challenges for local integrability and require further investigation. The techniques presented here are a first crucial step in formulating a systematic approach for constructing finite integrands for general electroweak amplitudes at three-loop order.
我们将局部减法框架扩展到夸克-反夸克湮灭中产生多重电弱玻色子的三环 QCD 校正。我们推导出了二回路沃德(Ward)等式,确保在积分总和中将硬散射过程中的大多数对偶奇异性因数化。红外和紫外奇异性是在环动量空间中利用一组最小反项逐点消除的,这些反项可以用已知的主积分进行分析积分。额外的反项消除了环动量偏移和胶子三点函数的一环修正所产生的非因子项。我们发现了先前未知的单共线区非因子环极化效应,这对局部可积分性提出了挑战,需要进一步研究。这里介绍的技术是为三环阶一般电弱振幅构建有限积分的系统方法迈出的关键性的第一步。
33. Type-II Seesaw Mechanism for Dirac Neutrinos and its Implications on $N_{\text{eff}}$ and Lepton Flavor Violationid:2502.01760:id在线阅读
Lucia Angel, Patricio Escalona, Vinícius Oliveira, C. A. de S. Pires, Farinaldo S. Queiroz
The type II seesaw is a popular mechanism for generating Majorana neutrino masses at the right scale, with well-known implications for Lepton Flavor Violation. In a non-abelian extension of the Standard Model featuring a Z' field, the type-II seesaw mechanism for Dirac neutrino masses naturally arises by imposing lepton number conservation and adding a soft-term breaking a $Z_2$ symmetry of the model. As expected, there are interesting outcomes for $\mu \rightarrow e \gamma$, but we noticed that the number of relativistic neutrinos, $N_{\text{eff}}$, has a greater impact driven by processes involving the $Z'$ boson and right-handed neutrinos. The presence of a gauge symmetry behind the physical processes, allows us to explore an interesting interplay between the type II seesaw, lepton flavor violation and $N_{\text{eff}}$. We find that using the indicated value by Planck $N_{\text{eff}}=2.99^{0.34}_{0.33}$ we impose constraints on the masses of the doubly charged scalar and Z' fields which are complementarity to direct searches at colliders.
II型跷跷板是在适当尺度上产生马约拉纳中微子质量的一种流行机制,它对轻子味道违反(Lepton Flavor Violation)有着众所周知的影响。在以Z'场为特征的标准模型的非阿贝尔扩展中,通过强加轻子数目守恒和增加一个破坏模型的$Z_2$对称性的软项,自然会产生狄拉克中微子质量的II型跷跷板机制。不出所料,$\mu \rightarrow e \gamma$的结果很有趣,但我们注意到,在涉及$Z'$玻色子和右手中微子的过程的驱动下,相对中微子的数量$N_{\text{eff}}$有更大的影响。物理过程背后存在的规对称性,使我们能够探索第二类跷跷板、轻子味道违反和 $N_{\text{eff}}$ 之间有趣的相互作用。我们发现,利用普朗克的指示值$N_{\text{eff}}=2.99^{0.34}_{0.33}$,我们对双电荷标量场和Z'场的质量施加了约束,这与对撞机的直接搜索是互补的。
34. Measurement of the presence of $\mathrm{a}_1(1420)$ and $ω(782)$ in $τ^-\toπ^-π^-π^+ν_τ$ at Belleid:2405.19264:id在线阅读
Andrei Rabusov, Daniel Greenwald, Stephan Paul
We present preliminary results of a partial-wave analysis of $\tau^-\to\pi^-\pi^-\pi^+\nu_\tau$ using data from the Belle experiment at the KEKB $\mathrm{e}^+\mathrm{e}^-$ collider. We validate our model with a model-independent analysis. We see the $\mathrm{a}_1(1420)$ and a G-parity-violating $1^-[\omega(782)\pi]_\mathrm{P}$ wave in tauon decays. Our results will improve models used in simulation studies necessary for measuring the electric and magnetic dipole moments and Michel parameters of the $\tau$.
我们利用在KEKB $\mathrm{e}^+\mathrm{e}^-$ 对撞机上进行的Belle实验的数据,介绍了对$\tau^-\to\pi^-\pi^-\pi^+\nu_\tau$的部分波分析的初步结果。我们通过与模型无关的分析验证了我们的模型。我们在陶子衰变中看到了$\mathrm{a}_1(1420)$和一个违反G 平分的$1^-[\omega(782)\pi]_\mathrm{P}$波。我们的结果将改进模拟研究中使用的模型,这些模型对于测量电偶极矩和磁偶极矩以及米歇尔参数(Michel parameters of the $\tau$ )是必不可少的。
35. Structure of Massive Gauge/Gravity Scattering Amplitudes, Equivalence Theorems, and Extended Double-Copy with Compactified Warped Spaceid:2406.12713:id在线阅读
Yanfeng Hang, Wei-Wei Zhao, Hong-Jian He, Yin-Long Qiu
We study the structure of scattering amplitudes of massive Kaluza-Klein (KK) states in the compactified 5-dimensional warped gauge and gravity theories. We present systematic formulations of the gauge theory equivalence theorem (GAET) and the gravitational equivalence theorem (GRET) for warped KK theories in $R_\xi^{}$ gauge, where the GAET connects the scattering amplitudes of longitudinal KK gauge bosons to that of the corresponding KK Goldstone bosons and the GRET connects the scattering amplitudes of KK gravitons of helicity-zero (helicity-one) to that of the corresponding gravitational scalar (vector) KK Goldstone bosons. We analyze the structure of 3-point and 4-point scattering amplitudes of massive KK gauge bosons and of massive KK gravitons as well as their corresponding Goldstone bosons. We first prove the GAET and GRET explicitly for the fundamental 3-point KK gauge/gravity scattering amplitudes. We then demonstrate that the validity of the GAET and GRET for 4-point gauge/gravity scattering amplitudes can be reduced to the validity of GAET and GRET for 3-point gauge/gravity scattering amplitudes at tree level. With these, we study the double-copy construction of KK scattering amplitudes in the warped gauge/gravity theories. We newly realize the double-copy for massive 3-point full gauge/gravity amplitudes at tree level under proper correspondences of color-kinematics and of gauge/gravity couplings, whereas we can construct the double-copy for 4-point KK gauge/gravity amplitudes to the leading order (LO) of high energy expansion. We also conjecture that this LO double-copy construction can be extended to $N$-point scattering amplitudes with $N\!\geqslant 5$.
我们研究了紧凑化五维翘曲规理论和引力理论中大质量卡鲁扎-克莱因(KK)态的散射振幅结构。我们提出了$R_\xi^{}$规中翘曲KK理论的规理论等价定理(GAET)和引力等价定理(GRET)的系统公式、其中,GAET 把纵向 KK 轨玻色子的散射振幅与相应的 KK 金斯通玻色子的散射振幅联系起来,而 GRET 则把氦度为零(氦度为一)的 KK 引力子的散射振幅与相应的引力标量(矢量)KK 金斯通玻色子的散射振幅联系起来。我们分析了大质量 KK 计玻色子和大质量 KK 引力子及其相应金石玻色子的 3 点和 4 点散射振幅的结构。我们首先明确证明了基本 3 点 KK 计/引力散射振幅的 GAET 和 GRET。然后,我们证明了 4 点规/引力散射振幅的 GAET 和 GRET 的有效性可以简化为树级 3 点规/引力散射振幅的 GAET 和 GRET 的有效性。有鉴于此,我们研究了翘曲规/引力理论中 KK 散射振幅的双拷贝构造。在色彩运动学和规规/引力耦合的适当对应关系下,我们新近实现了树级的大质量3点全规规/引力振幅的双拷贝,而我们可以为4点KK规规/引力振幅构建高能扩展前导阶(LO)的双拷贝。我们还猜想,这种LO双拷贝构造可以扩展到具有$N\!\geqslant 5$的$N$点散射振幅。
36. Interpreting Pulsar Timing Array data of Gravitational Waves with Ekpyrosis-Bouncing Cosmologyid:2408.06582:id在线阅读
Taotao Qiu, Mian Zhu
Recent pulsar timing array (PTA) experiments have reported strong evidence of the stochastic gravitational wave background (SGWB). If interpreted as primordial Gravitational Waves (pGWs), the signal favors a strongly blue-tilted spectrum. On the other hand, the Ekpyrosis-bouncing cosmology with a strongly blue-tilted GW spectrum, i.e., $n_T \simeq 2$, offers a potential explanation for the observed SGWB signal. In this paper, we construct a concrete Ekpyrosis-bouncing model, and show its capacity to intepret the PTA result without pathologies. Both tensor and scalar perturbations are analysed with constraints from the current observations.
最近的脉冲星定时阵列(PTA)实验报告了随机引力波背景(SGWB)的有力证据。如果将其解释为原始引力波(pGWs),则信号倾向于强烈的蓝色倾斜频谱。另一方面,具有强蓝倾斜引力波频谱(即$n_T \simeq 2$)的Ekpyrosis-bouncing宇宙学为观测到的SGWB信号提供了一种潜在的解释。在本文中,我们构建了一个具体的 "Ekpyrosis-bouncing "模型,并展示了它无病理地解释PTA结果的能力。张量和标量扰动都是在当前观测的约束下进行分析的。
37. Finite- and infinite-volume study of $DDπ$ scatteringid:2409.17059:id在线阅读
Sebastian M. Dawid, Fernando Romero-López, Stephen R. Sharpe
We develop a comprehensive framework for extracting the pole position and properties of the doubly-charmed tetraquark $T_{\rm cc}^+(3875)$ from lattice QCD data using the relativistic three-particle formalism. This approach incorporates the effect of the one-pion exchange diagram in $DD\pi$ and $DD^*$ scattering, making it applicable at energies coinciding with the left-hand cut in the partial-wave projected $DD^*$ amplitude. We present an example application of this framework to existing lattice QCD data at $m_\pi = 280$ MeV. We solve the integral equations describing the $DD\pi$ reaction, use LSZ reduction to determine the corresponding $DD^*$ amplitude, and find the values of the infinite-volume two- and three-body $K$ matrices that lead to agreement with lattice $DD^*$ phase shifts within their uncertainties. Using these $K$ matrices in the three-particle quantization condition, we describe the finite-volume $DD^*$ spectrum and find good agreement with the lattice QCD energies. Our results suggest that, at this pion mass, the tetraquark appears as a pair of subthreshold complex poles whose precise location strongly depends on the value of the $DD\pi$ three-particle $K$ matrix.
我们建立了一个综合框架,利用相对论三粒子形式主义从格子QCD数据中提取双粲四夸克$T_{\rm cc}^+(3875)$ 的极点位置和性质。这种方法结合了$DD\pi$和$DD^*$散射中的单粒子交换图的影响,使其适用于与部分波投影的$DD^*$振幅的左手切点相吻合的能量。我们举例说明了这一框架在 $m_\pi = 280$ MeV 时对现有晶格 QCD 数据的应用。我们求解了描述 $DD\pi$ 反应的积分方程,使用 LSZ 还原法确定了相应的 $DD^*$ 振幅,并找到了导致与晶格 $DD^*$ 相移在不确定范围内一致的无限体积二体和三体 $K$ 矩阵的值。在三粒子量子化条件下使用这些 $K$ 矩阵,我们描述了有限体积 $DD^*$ 谱,并发现与晶格 QCD 能量有很好的一致性。我们的结果表明,在这种先锋质量下,四夸克是以一对亚阈值复极的形式出现的,其精确位置很大程度上取决于 $DD\pi$ 三粒子 $K$ 矩阵的值。
38. Tidal Love numbers of gravitational atomsid:2410.00968:id在线阅读
Ricardo Arana, Richard Brito, Gonçalo Castro
Ultralight bosonic fields can form condensates, or clouds, around spinning black holes. When this system is under the influence of a secondary massive body, its tidal response can be quantified in the tidal Love numbers (TLNs). Although TLNs vanish for black holes in vacuum, it has been shown that the same is not true for black holes immersed in matter environments. In this work, we compute the gravitational TLNs of black holes surrounded by scalar clouds, in the Newtonian limit. We show that they are non-vanishing, have a strong power-law dependence on the boson's mass, and are proportional to the scalar cloud's total mass. In particular, we find that, independently of the cloud's configuration, the TLNs from axisymmetric tides scale as $\propto r_c^{2l+1}$, for $r_c$ the cloud's "radius" and $l$ the multipole order of the external tidal field. This differs by a factor $r_c$ from previous estimates based on scalar and vector tidal perturbations but is in perfect agreement with the behavior of TLNs in other matter systems. Furthermore, we show that the adiabatic tides approximation we employ is, in general, not appropriate for non-axisymmetric tidal interactions.
超轻玻色场可以在旋转黑洞周围形成凝聚体或云。当这个系统受到次级大质量天体的影响时,它的潮汐反应可以用潮汐爱数(TLNs)来量化。虽然对于真空中的黑洞来说,TLNs 消失了,但对于沉浸在物质环境中的黑洞来说,情况却并非如此。在这项研究中,我们计算了牛顿极限下被标量云包围的黑洞的引力 TLNs。结果表明,它们是非消失的,与玻色子的质量有很强的幂律关系,并且与标量云的总质量成正比。特别是,我们发现,与云的构型无关,来自轴对称潮汐的 TLNs 的尺度为 $\propto r_c^{2l+1}$,其中 $r_c$ 是云的半径',$l$ 是外部潮汐场的多极阶。这与之前基于标量和矢量潮汐扰动的估计值相差 $r_c$,但与其他物质系统中 TLN 的行为完全一致。此外,我们还证明了我们采用的绝热潮汐近似一般不适合非轴对称潮汐相互作用。
39. Calculation of heavy meson light-cone distribution amplitudes from lattice QCDid:2410.18654:id在线阅读
Xue-Ying Han, Jun Hua, Xiangdong Ji, Cai-Dian Lü, Andreas Schäfer, Yushan Su, Wei Wang, Ji Xu, Yibo Yang, Jian-Hui Zhang, Qi-An Zhang, Shuai Zhao
We develop an approach for calculating heavy quark effective theory (HQET) light-cone distribution amplitudes (LCDAs) by employing a sequential effective theory methodology. The theoretical foundation of the framework is established, elucidating how the quasi distribution amplitudes (quasi DAs) with three scales can be utilized to compute HQET LCDAs. We provide theoretical support for this approach by demonstrating the rationale behind devising a hierarchical ordering for the three involved scales, discussing the factorization at each step, clarifying the underlying reason for obtaining HQET LCDAs in the final phase, and addressing potential theoretical challenges. The lattice QCD simulation aspect is explored in detail, and the computations of quasi DAs are presented. We employ three fitting strategies to handle contributions from excited states and extract the bare matrix elements. For renormalization purposes, we apply hybrid renormalization schemes at short and long distance separations. To mitigate long-distance perturbations, we perform an extrapolation in $\lambda= z\cdot P^z$ and assess the stability against various parameters. After two-step matching, our results for HQET LCDAs are found in agreement with existing model parametrizations. The potential phenomenological implications of the results are discussed, shedding light on how these findings could impact our understanding of the strong interaction dynamics and physics beyond the standard model. It should be noted, however, that systematic uncertainties have not been accounted for yet.
我们开发了一种利用顺序有效理论方法计算重夸克有效理论(HQET)光锥分布振幅(LCDAs)的方法。我们建立了这一框架的理论基础,阐明了如何利用具有三个尺度的准分布振幅(quasi DAs)来计算 HQET LCDAs。我们为这种方法提供了理论支持,展示了为三个相关尺度设计分层排序的原理,讨论了每一步的因式分解,阐明了在最后阶段获得 HQET LCDA 的根本原因,并解决了潜在的理论挑战。我们详细探讨了格子 QCD 模拟方面的问题,并介绍了准 DAs 的计算。我们采用了三种拟合策略来处理激发态的贡献并提取裸矩阵元素。为了实现重正化,我们在短距离和长距离分离时采用了混合重正化方案。为了减轻长距离扰动,我们在 $\lambda= z\cdot P^z$ 中进行了外推,并评估了各种参数的稳定性。经过两步匹配,我们发现 HQET LCDAs 的结果与现有模型参数化的结果一致。我们讨论了这些结果的潜在现象学意义,揭示了这些发现会如何影响我们对标准模型之外的强相互作用动力学和物理学的理解。但应该注意的是,系统不确定性尚未考虑在内。
40. String Breaking in the Heavy Quark Limit with Scalable Circuitsid:2411.05915:id在线阅读
Anthony N. Ciavarella
Quantum simulations of non-Abelian gauge theories require efficient mappings onto quantum computers and practical state preparation and measurement procedures. A truncation of the Hilbert space of non-Abelian lattice gauge theories with matter in the heavy quark limit is developed. This truncation is applied to $SU(2)$ lattice gauge theory in $1+1D$ to map the theory efficiently onto a quantum computer. Scalable variational circuits are found to prepare the vacuum and single meson states. It is also shown how these state preparation circuits can be used to perform measurements of the number of mesons produced during the system's time evolution. A state with a single $q\overline{q}$ pair is prepared on quantum hardware and the inelastic production of $q\overline{q}$ pairs is observed using $104$ qubits on IBM's Heron quantum computer ibm_torino.
非阿贝尔规理论的量子模拟需要量子计算机上的高效映射以及实用的状态准备和测量程序。我们开发了重夸克极限物质非阿贝尔格规理论希尔伯特空间的截断。这种截断被应用于$1+1D$的$SU(2)$格规理论,以将该理论有效地映射到量子计算机上。研究发现了制备真空态和单介子态的可扩展变分电路。研究还展示了如何利用这些态制备电路来测量系统时间演化过程中产生的介子数量。在量子硬件上制备了具有单个 $q\overline{q}$ 对的状态,并在 IBM's Heron 量子计算机 ibm_torino 上使用 $104$ 量子比特观测了 $q\overline{q}$ 对的非弹性产生。
41. Cosmic Topological Defects from Holographyid:2411.19302:id在线阅读
Francesco Bigazzi, Aldo L. Cotrone, Andrea Olzi
This work investigates cosmic topological defects in gauge theories, focusing on models with an $SU(N)$ gauge group coupled with a single flavor, explored through a holographic framework. At low energies, the effective theory is described by an axion-like particle resulting from the spontaneous breaking of the axial $U(1)_A$ flavor symmetry. As the Universe cools below a critical temperature, the chiral symmetry is broken, and non-trivial vacuum configurations form, resulting in the creation of cosmic strings and domain walls. We provide a UV description of these defects in a particular holographic theory, the Witten-Sakai-Sugimoto model, as probe D6-branes. We show the presence of a first-order phase transition separating string loop from domain wall solutions. String loops charged under the baryon symmetry and with angular momentum - vortons - can be understood as excitations of a topological phase of matter given by a Chern-Simons theory living on the D6-brane world volume. Finally, we provide an effective description of string loops and vortons in terms of degrees of freedom living on the flavor brane, i.e. mesonic modes.
这项工作研究了规规理论中的宇宙拓扑缺陷,重点是通过全息框架探索与单一味道耦合的$SU(N)$规规群模型。在低能情况下,有效理论由轴向 $U(1)_A$ 味对称性自发破缺产生的类轴子粒子来描述。当宇宙冷却到临界温度以下时,手性对称性被打破,形成非三维真空构型,导致宇宙弦和域壁的产生。我们用紫外光描述了一种特殊的全息理论--维滕-堺-杉本模型--中的这些缺陷,并将其视为探针 D6 粒子。我们证明了弦环与畴壁解之间存在一阶相变。在重子对称性下带电并具有角动量的弦环--涡子--可以被理解为生活在 D6rane 世界卷上的切尔-西蒙斯理论给出的物质拓扑相的激发。最后,我们用生活在风味线上的自由度(即介子模式)来有效描述弦环和涡子。
42. The Status of Neutrino Cosmology: Standard $Λ$CDM, Extensions, and Tensionsid:2412.05451:id在线阅读
Helena García Escudero, Kevork N. Abazajian
We examine the performance of the six-parameter $\Lambda$CDM model and its extensions in light of recent cosmological observations, with particular focus on neutrino properties inferred from cosmology. Using a broad suite of nine combinations of datasets, with three separate analyses of the Planck Cosmic Microwave Background (CMB) data, and three separate supernovae (SNe) survey data, plus the recent DESI baryon acoustic oscillation (BAO) scale results, we derive constraints on the sum of neutrino masses ($\Sigma m_\nu$). Our results show upper limits in the range of $\Sigma m_\nu < 76.9\,\mathrm{meV}$ to $\Sigma m_\nu < 108\,\mathrm{meV}$ (95\% CL). The variation in the limits on $\Sigma m_\nu$ arises from the separate analyses of the Planck CMB data and the separate supernovae datasets, as they relate to the inferred matter density and its relation to the sensitivity of the BAO scale and CMB lensing to $\Sigma m_\nu$. In the context of hierarchical mass models in $\Lambda$CDM, we find a $1.47\sigma$ preference for normal ordering (NO) over inverted ordering (IO), with similar values of preference across all datasets. Despite the strong constraints, an inclination towards massless neutrinos over NO remains weak at $1.36\sigma$. We find that a ``negative'' neutrino mass, inferred from the shape of the likelihood in the physical regime, $\Sigma m_\nu > 0$, is only present at less than $2\sigma$. We confirm that models allowing extra relativistic degrees of freedom, with $N_{\rm eff} \approx 3.5$, alleviate the Hubble tension. Significantly, we find a $3.3\sigma$ preference for a 0.1 eV partially thermalized sterile neutrino when the SH0ES $H_0$ measurement is included, a scale of interest in short-baseline oscillation experiment results. [abridged]
我们根据最近的宇宙学观测,特别是根据宇宙学推断的中微子特性,检验了六参数$\Lambda$CDM模型及其扩展的性能。我们使用了一套广泛的九种数据集组合,其中包括对普朗克宇宙微波背景(CMB)数据的三次单独分析、三次单独的超新星(SNe)巡天数据,以及最近的DESI重子声振荡(BAO)尺度结果,得出了对中微子质量总和($\Sigma m_\nu$)的约束。我们的结果显示了在$\Sigma m_\nu < 76.9\\mathrm{meV}$ 到$\Sigma m_\nu < 108\\mathrm{meV}$ (95% CL)范围内的上限。对$\Sigma m_\nu$的限制的变化来自对普朗克CMB数据和超新星数据集的单独分析,因为它们与推断的物质密度及其与BAO尺度和CMB透镜对$\Sigma m_\nu$的敏感性的关系有关。在$\Lambda$CDM中的层次质量模型的背景下,我们发现正常排序(NO)比倒序(IO)的偏好值高1.47\sigma$,所有数据集的偏好值相似。尽管有很强的约束条件,但无质量中微子比正常中微子的倾向仍然很弱,只有1.36 (sigma$)。我们发现,中微子质量的 "负'',是根据物理机制中的可能性形状推断出来的,$\Sigma m_\nu > 0$,只存在于小于2\sigma$时。我们证实,允许额外相对论自由度的模型,其N_{\rm eff} 为$N_{\rm eff} 。\约 3.5$,可以缓解哈勃张力。值得注意的是,我们发现当包括 SH0ES $H_0$ 测量时,0.1 eV 部分热化的不育中微子有 3.3sigma$ 的偏好,这是短基线振荡实验结果中的一个关注尺度。[有删节]