Fri·Feb 16, 2024Friday·February 16, 2024

1. 01*

   On magnitudes of some CKM matrix elements

   Zoltan Ligeti🇺🇸

   This writeup follows the presentation at the Symposium, with emphasis on topics and ideas discussed there. It is purposefully informal, not a review of the field, and neither does it include a complete list of references. However, I hope that readers might find some comments useful or amusing, and may appreciate the challenges and reasons for excitement about recent progress and future opportunities in flavor physics.

   hep-phhep-exPTEP(2025)·0 citations
2. 02*

   Secondary massive quarks with the Mellin-Barnes expansion

   Alejandro Bris🇪🇸 · Vicent Mateu🇪🇸

   Processes involving only massless or massive quarks at tree-level get corrections from massive (lighter, heavier, or equal-mass) secondary quarks starting at two-loop order, generated by a virtual gluon splitting into a massive quark anti-quark pair. One convenient approach to compute such two-loop corrections is starting with the one-loop diagram considering the virtual gluon massive. Carrying out a dispersive integral with a suitable kernel over the gluon mass yields the desired two-loop result. On the other hand, the Mellin-Barnes representation can be used to compute the expansion of Feynman integrals in powers of a small parameter. In this article we show how to combine these two ideas to obtain the corresponding expansions for large and small secondary quark masses to arbitrarily high orders in a straightforward manner. Furthermore, the convergence radius of both expansions can be shown to overlap, being each series rapidly convergent. The advantage of our method is that the Mellin representation is obtained directly for the full matrix element from the same one-loop computation one needs in large-${\beta }_0$ computations, therefore many existing results can be recycled. With minimal modifications, the strategy can be applied to compute the expansion of the one-loop correction coming from a massive gauge boson. We apply this method to a plethora of examples, in particular those relevant for factorized cross sections involving massless and massive jets, recovering known results and obtaining new ones. Another bonus of our approach is that, postponing the Mellin inversion, one can obtain the small- and large-mas expansions for the RG-evolved jet functions. In many cases, the series can be summed up yielding closed expressions.

   hep-phJHEP(2024)·4 citations
3. 03*

   Constraints on the Variation of Physical Constants, Equivalence Principle Violation, and a Fifth Force from Atomic Experiments

   V. A. Dzuba🇦🇺 · V. V. Flambaum🇦🇺 · A. J. Mansour🇦🇺

   The aim of this paper is to derive limits on various forms of ``new physics'' using atomic experimental data. Interactions with dark energy and dark matter fields can lead to space-time variations of fundamental constants, which can be detected through atomic spectroscopy. In this study, we examine the effects of a varying nuclear mass $m_N$ and nuclear radius $r_N$ on two transition ratios: the comparison of the two-photon transition in atomic hydrogen with the hyperfine transition in ${}^{133}$Cs based clocks, and the ratio of optical clock frequencies in in Al${}^{+}$ and Hg${}^{+}$. The sensitivity of these frequency ratios to changes in $m_N$ and $r_N$ enables us to derive new limits on the variations of the proton mass, quark mass, and the QCD parameter $\theta$. Additionally, we consider the scalar field generated by the Yukawa-type interaction of feebly interacting hypothetical scalar particles with Standard Model particles in the presence of massive bodies such as the Sun and Moon. Using the data from the Al${}^{+}$/Hg${}^{+}$, Yb${}^{+}$/Cs and Yb${}^{+}$(E2)/Yb${}^{+}$(E3) transition frequency ratios, we place constraints on the interaction of the scalar field with photons, nucleons, and electrons for a range of scalar particle masses. We also investigate limits on the Einstein Equivalence Principle (EEP) violating term ($c_{00}$) in the Standard Model Extension (SME) Lagrangian and the dependence of fundamental constants on gravity.

   hep-phnucl-thphysics.atom-phPRD(2024)·13 citations
4. 04*

   Light-shinning-through-thin-wall radio frequency cavities for probing dark photon

   Dmitry Salnikov🇷🇺 · Petr Satunin🇷🇺 · Leysan Valeeva🇷🇺 · D. V. Kirpichnikov🇷🇺

   We address the radio frequency (RF) cavity experiment for probing dark photons, which is a modification of the light-shining-through-thin-wall (LSthinW) setup with a relatively thin conducting barrier between cylindrical emitter and hollow We address the radio frequency (RF) cavity experiment for probing dark photons, which is a modification of the light-shining-through-thin-wall (LSthinW) setup with a relatively thin conducting barrier between a cylindrical emitter and a hollow receiver. The experimental facility allows for the effective probing of dark photons even in the off-shell regime, i.e., when the dark photon mass exceeds the driving frequency of the emitter cavity, which is pumped by an electromagnetic mode. We compare the sensitivity of two specific setup configurations: (i) two adjacent cylindrical cavities placed end-to-end with an end-cap separating them, and (ii) a nested geometry in which the cylindrical receiver is encapsulated within the emitter. We demonstrate that, for a certain range of dark photon masses, the nested configuration with the $\text{mbox}{TM}_{010}$ pump mode can provide enhanced sensitivity compared to an adjacent emitter setup. Remarkably, for the $\text{mbox}{TE}_{011}$ pump mode, both the nested and adjacent cavity configurations can yield comparable expected reaches for the specific geometry type.

   hep-phEPJC(2025)·1 citation
5. 05*

   NSI effects on tripartite entanglement in neutrino oscillations

   Lekhashri Konwar🇮🇳 · Bhavna Yadav🇮🇳

   In this study, we investigate the impact of new physics on different measures of tripartite entanglement within the context of three-flavor neutrino oscillations. These measures encompass concurrence, entanglement of formation, and negativity. We analyze the influence of new physics on these measures across a range of experimental setups involving both reactors and accelerators. Reactor experiments under consideration include Daya Bay, JUNO, and KamLAND setups, while accelerator experiments encompass T2K, MINOS, and DUNE. Our analysis reveals that accelerator experiments demonstrate greater sensitivity to NSI, with the most pronounced impact observed in the DUNE experiment. Negativity, while a weaker metric compared to EOF and concurrence, exhibits maximal sensitivity to NSI effects, particularly evident when neutrinos possess moderate to high energies. Conversely, reactor experiments demonstrate less sensitivity to NSI, with concurrence and EOF displaying more prominent effects.

   hep-phNPB(2024)·14 citations
6. 06*

   Ad interim recommendations for the Higgs boson production cross sections at $\sqrt{s}=13.6$ TeV

   Alexander Karlberg🇨🇭 · Julie Malcles🇫🇷 · Bernhard Mistlberger🇺🇸 · Roberto Di Nardo🇮🇹 · Syed Haider Abidi🇺🇸 · Robin Hayes🇳🇱 · Alexander Huss🇨🇭 · Stephen Jones🇬🇧 · Gaetano Barone🇺🇸 · Jiayi Chen🇨🇦 · Stephane Cooperstein🇺🇸 · Silvia Ferrario Ravasio🇨🇭 and 12 other authors

   This note documents predictions for the inclusive production cross sections of the Standard Model Higgs boson at the Large Hadron Collider at a centre of mass energy of 13.6 TeV. The predictions here are based on simple extrapolations of previously documented predictions published in the CERN Yellow Report "Deciphering the Nature of the Higgs Sector". The predictions documented in this note should serve as a reference while a more complete and update-to-date derivation of cross section predictions is in progress.

   hep-phhep-ex54 citations
7. 07*

   Measuring the angle ${\alpha }_{ds}$ of the flattest Unitary Triangle with ${\overline{B}}_d\to \varphi {\overline{K}}^{(\ast )0},{\overline{B}}_s\to \varphi K^{(\ast )0}$ decays

   Roy Aleksan🇫🇷 · Luis Oliver🇫🇷 · Emmanuel Perez🇨🇭

   We show that the angle ${\alpha }_{ds}$ of the ``flattest'' unitarity triange can be directly measured using the decays ${\overline{B}}_d\to \varphi {\overline{K}}^{(\ast )0}$ and ${\overline{B}}_s\to \varphi K^{(\ast )0}$. Using both ${\overline{B}}_d$ and ${\overline{B}}_s$ enables a further consistency test since the expected time-dependent CP violating asymmetries are identical though with opposite signs. Since large statistics of ${\overline{B}}_d$ and ${\overline{B}}_s$ are needed for accurate measurements, FCC-ee and its environment at the Z-pole is well suited for such studies. These measurements, the precision of which could reach the sub-degree level, will contribute to probe further the consistency of the CP sector of the Standard Model with unprecedented level of accuracy. The main detector requirements that are set by these measurements are also outlined.

   hep-ph4 citations
8. 08*

   Manifestations of CP Violation in the B Meson System: Theoretical Perspective

   Eleftheria Malami🇩🇪

   CP violation in the field of $B$ physics is a crucial topic for exploring the quark sector and search for New Physics, both for theorists and experimentalists. CP violation manifests itself in various ways and in this presentation, we will categorise the decays based on their different dynamics. We aim to present highlights related to the studies of CP violation in each category from a theoretical perspective.

   hep-phPoS(2024)·2 citations
9. 09*

   Reconstructing short-lived particles using hypergraph representation learning

   Callum Birch-Sykes🇬🇧 · Brian Le🇬🇧 · Yvonne Peters🇬🇧 · Ethan Simpson🇬🇧 · Zihan Zhang🇬🇧

   In collider experiments, the kinematic reconstruction of heavy, short-lived particles is vital for precision tests of the Standard Model and in searches for physics beyond it. Performing kinematic reconstruction in collider events with many final-state jets, such as the all-hadronic decay of top-antitop quark pairs, is challenging. We present HyPER: Hypergraph for Particle Event Reconstruction, a novel architecture based on graph neural networks that uses hypergraph representation learning to build more powerful and efficient representations of collider events. HyPER is used to reconstruct parent particles from sets of final-state objects. Trained and tested on simulation, the HyPER model is shown to perform favorably when compared to existing state-of-the-art reconstruction techniques, while demonstrating superior parameter efficiency. The novel hypergraph approach allows the method to be applied to particle reconstruction in a multitude of different physics processes.

   hep-phPRD(2025)·10 citations
10. 10*

    Squark production with R-symmetry beyond NLO at the LHC

    Christoph Borschensky🇩🇪 · Fausto Frisenna🇵🇱 · Wojciech Kotlarski · Anna Kulesza🇩🇪 · Dominik Stöckinger🇩🇪

    The Minimal R-symmetric Supersymmetric Standard Model (MRSSM) provides a realisation of supersymmetry in which the parameter space is less constrained by the current LHC data than in the simplest supersymmetric scenarios. In the present paper, we obtain the most precise theoretical predictions in the MRSSM for squark production at the LHC, enabling accurate interpretations of LHC data in terms of the MRSSM. We perform threshold resummation of soft gluon corrections to the total cross sections for the production of squark-(anti)squark pairs at the LHC in the MRSSM framework. The resummation is carried out using the direct QCD method and reaches the next-to-next-to-leading-logarithmic (NNLL) accuracy, which requires calculating the one-loop matching coefficients in the relevant production channels. The resummed cross sections are then matched to the available NLO results and evaluated for $\sqrt{S}=13.6$ TeV. Compared with the Minimal Supersymmetric Standard Model (MSSM), the cross sections in the MRSSM can be significantly reduced, implying less stringent limits on squark and gluino masses. Our results carry significant implications for exploring the viability of supersymmetry at the LHC. The results of our calculation are publicly available as a numerical package.

    hep-phhep-exJHEP(2024)·5 citations
11. 11*

    Lepto-axiogenesis with light right-handed neutrinos

    Patrick Barnes🇺🇸 · Raymond T. Co🇺🇸 · Keisuke Harigaya🇺🇸 · Aaron Pierce🇺🇸

    We study lepto-axiogenesis in theories where the right-handed neutrino is light enough that its dynamics affect the determination of the baryon asymmetry. When compared with theories of high-scale lepto-axiogenesis where the Majorana neutrino mass may be treated as an effective dimension-five operator, we find that the predicted saxion mass is lower. Two distinct scenarios emerge. In the first, processes that generate the baryon asymmetry are in equilibrium down to the mass of the right-handed neutrino. In the second, the relevant processes never reach equilibrium; the baryon number freezes in. We comment on implications for supersymmetric spectra and discuss constraints on late decays of supersymmetric relics and from dark radiation. In contrast to high-scale lepto-axiogenesis, which predicts superpartners with masses of 10-100 TeV or more, we find this scenario is consistent with a wider range of superpartner masses, all the way down to current direct search bounds.

    hep-phastro-ph.COJHEP(2025)·21 citations
12. 12*

    Neutrino-Dark Sector Equilibration and Primordial Element Abundances

    Cara Giovanetti🇺🇸 · Martin Schmaltz🇺🇸 · Neal Weiner🇺🇸

    After neutrinos decouple from the photon bath, they can populate a thermal dark sector. If this occurs at a temperature above ~100 keV, this can have measurable impacts on light element abundances. We calculate light element abundances in this scenario, studying the impact from rapid cooling of the Standard Model neutrinos, and from an increase in the number of relativistic degrees of freedom $N_{\mathrm{eff}}$, which can occur in the presence of a mass threshold. We incorporate these changes in the publicly available BBN code PRIMAT, using the reaction networks from PRIMAT and from the BBN code PArthENoPE, to calculate Y${}_{\mathrm{P}}$ and D/H. We provide limits from the two different reaction networks as well as with expanded errors to include both results. If electron neutrinos significantly participate in the cooling, we find limits down to temperatures as low as 100 keV. If electron neutrinos are weakly participating (for instance if only the mass eigenstate ${\nu }_3$ equilibrates), cooling places no limits. However, if the dark sector undergoes a "step" in $N_{\mathrm{eff}}$, there can be additional, ${\omega }_b$-dependent constraints. These limits can vary from strong (for low values of ${\omega }_b$) to a mild preference for new physics (for high values of ${\omega }_b$). Future analyses including upcoming CMB data should improve these limits.

    hep-phastro-ph.COPRD(2025)·15 citations
13. 13*

    Quantum Simulation of SU(3) Lattice Yang Mills Theory at Leading Order in Large N

    Anthony N. Ciavarella🇺🇸 · Christian W. Bauer🇺🇸

    Quantum simulations of the dynamics of QCD have been limited by the complexities of mapping the continuous gauge fields onto quantum computers. By parametrizing the gauge invariant Hilbert space in terms of plaquette degrees of freedom, we show how the Hilbert space and interactions can be expanded in inverse powers of N_c. At leading order in this expansion, the Hamiltonian simplifies dramatically, both in the required size of the Hilbert space as well as the type of interactions involved. Adding a truncation of the resulting Hilbert space in terms of local energy states we give explicit constructions that allow simple representations of SU(3) gauge fields on qubits and qutrits. This formulation allows a simulation of the real time dynamics of a SU(3) lattice gauge theory on a 5x5 and 8x8 lattice on ibm_torino with a CNOT depth of 113.

    hep-phhep-latquant-phPRL(2024)·132 citations
14. 14*

    Anomalous conductivity due to relativistic Landau quantization

    Gert Brodin🇸🇪 · Haidar Al-Naseri🇸🇪

    We use a recently developed kinetic model derived from the Dirac equation, in order to study electromagnetic wave propagation in superstrong magnetic fields, such as in magnetars, where relativistic Landau quantization is prominent. The leading contribution to the conductivity tensor in such a plasma is calculated. It is found that the electron Hall current has an anomalous contribution, in the quantum relativistic regime, where the effective particle energy has a significant contribution from the diamagnetic and Zeeman energy. As a result, a new quantum resonance frequency appears, and the dispersion relation for the left- and right-hand polarized modes are strongly modified for long and moderate wavelengths. The implications for magnetar physics are discussed.

    ↳ physics.plasm-phhep-phPRE(2024)·1 citation
15. 15*

    Hydrodynamization and resummed viscous hydrodynamics

    Michael Strickland🇺🇸

    In this contributed chapter, I review our current understanding of the applicability of hydrodynamics to modeling the quark-gluon plasma (QGP), focusing on the question of hydrodynamization/thermalization of the QGP and the anisotropic hydrodynamics (aHydro) far-from-equilibrium hydrodynamic framework. I discuss the existence of far-from-equilibrium hydrodynamic attractors and methods for determining attractors within different hydrodynamical frameworks. I also discuss the determination of attractors from exact solutions to the Boltzmann equation in relaxation time approximation and effective kinetic field theory applied to quantum chromodynamics. I then present comparisons of the kinetic attractors with the attractors obtained in standard second-viscous hydrodynamics frameworks and anisotropic hydrodynamics. I demonstrate that, due to the resummation of terms to all orders in the inverse Reynolds number, the anisotropic hydrodynamics framework can describe both the weak- and strong-interaction limits. I then review the phenomenological application of anisotropic hydrodynamics to relativistic heavy-ion collisions using both quasiparticle aHydro and second-order viscous aHydro. The phenomenological results indicate that aHydro provides a controlled extension of dissipative relativistic hydrodynamics to the early-time far-from-equilibrium stage of heavy-ion collisions. This allows one to better describe the data and to extract the temperature dependence of transport coefficients at much higher temperatures than linearized second-order viscous hydrodynamics.

    ↳ nucl-thhep-phIJMPE(2024)·14 citations
16. 16*

    One-loop vacuum energy in 10D super-Yang-Mills theory on magnetized tori with/without 4D N=1 supersymmetric completion

    Hiroyuki Abe🇯🇵 · Akinari Koichi🇯🇵 · Yusuke Yamada🇯🇵

    We compute the one-loop vacuum energy in 10 dimensional (10D) super Yang-Mills theory compactified on ${\mathbb{R}}^{1,3}\times ({\mathbb{T}}^2{)}^3$ in the presence of the Abelian magnetic fluxes. The regularization of infinite Kaluza-Klein (KK) sum is achieved by the use of Barnes $\zeta$-functions, which can be applied to the case with Landau level structure of KK mass spectrum. We apply the technique to two different models of the 10D super Yang-Mills theory: The one is to introduce the magnetic flux background to the 10D super Yang-Mills action. The other is to first embed 10D super Yang-Mills action into 4D $\mathcal{N}=1$ superspace and to introduce magnetic fluxes. The two model buildings result in tree level potential. The KK mass spectrum of two models look different and we compute the one-loop vacuum energy of each case. Nevertheless, both of the KK mass spectra have the Landau level structure and we can apply the regularization method in the same way. We show that despite the differences the resultant one-loop vacuum energy of both models coincide with each other.

    ↳ hep-thhep-phPTEP(2024)·1 citation
17. 17*

    Neutron Stars constraints on a late G transition

    Itzhak Goldman🇮🇱

    It has been suggested recently that the Hubble tension could be eliminated by a sharp, $\sim 10\%$ increase of the effective gravitational constant at $z\sim 0.01$. This would decrease the luminosities of type 1a supernovae in just the needed amount to explain the larger value of the Hubble parameter. In the present paper we call attention to a dramatic effect of such transition on neutron stars. A neutron star that existed at $z=0.01$ would contract, conserving the baryon mass but undergoing a mass reduction. We computed neutron star models, with a realistic equation of state, and obtained that this reduction is typically $0.04M_{\odot }$. This amounts to an energy of $7\times 10^{52}$ erg. The transition will affect {\it all} neutron stars that formed along the history of each galaxy prior to the transition. Given the large number of neutron stars per galaxy, the liberated energy is huge. An estimate of the expected fluxes of neutrinos and x-rays yields values exceeding observational upper limits, thus rendering the late G transition scenario non-viable.

    ↳ astro-ph.COhep-phPLB(2024)·3 citations
18. 18*

    Double-well instantons in finite volume

    Wen-Yuan Ai🇬🇧 · Jean Alexandre🇬🇧 · Matthias Carosi🇩🇪 · Bjorn Garbrecht🇩🇪 · Silvia Pla🇬🇧

    Assuming a toroidal space with finite volume, we derive analytically the full one-loop vacuum energy for a scalar field tunnelling between two degenerate vacua, taking into account discrete momentum. The Casimir energy is computed for an arbitrary number of dimensions using the Abel-Plana formula, while the one-loop instanton functional determinant is evaluated using the Green's functions for the fluctuation operators. The resulting energetic properties are non-trivial: both the Casimir effect and tunnelling contribute to the Null Energy Condition violation, arising from a non-extensive true vacuum energy. We discuss the relevance of this mechanism to induce a cosmic bounce, requiring no modified gravity or exotic matter.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2024)·9 citations
19. 19*

    An Étude on the Regularization and Renormalization of Divergences in Primordial Observables

    Anna Negro🇳🇱 · Subodh P. Patil🇳🇱

    Many cosmological observables of interest derive from primordial vacuum fluctuations evolved to late times. These observables represent statistical draws from some underlying quantum or statistical field theoretic framework where infinities arise and require regularization. After subtracting divergences, renormalization conditions must be imposed by measurements or observations at some scale, mindful of scheme and background dependence. We review this process on backgrounds that transition from finite duration inflation to radiation domination, and show how in spite of the ubiquity of scaleless integrals, UV divergences can still be meaningfully extracted from quantities that nominally vanish when dimensionally regularized. In this way, one can contextualize calculations with hard cutoffs, distinguishing between UV and IR scales corresponding to the beginning and end of inflation from UV and IR scales corresponding the unknown completion of the theory and its observables. This distinction has significance as observable quantities cannot depend on the latter although they will certainly depend on the former. One can also explicitly show the scheme independence of the coefficients of UV divergent logarithms. Furthermore, certain IR divergences can be shown to be an artifact of the de Sitter limit and are cured for finite duration inflation. For gravitational wave observables, we stress the need to regularize stress tensors that do not presume a prior scale separation in their construction (as with the standard Isaacson form), deriving an improved stress tensor fit to purpose. We conclude by highlighting the inextricable connection between inferring $N_{\mathrm{eff}}$ bounds from vacuum tensor perturbations and the process of background renormalization.

    ↳ hep-thastro-ph.COgr-qchep-phRiv.Nuovo Cim.(2024)·14 citations
20. 20*

    The QCD phase diagram and Beam Energy Scan physics: a theory overview

    Lipei Du🇨🇦 · Agnieszka Sorensen🇺🇸 · Mikhail Stephanov🇺🇸

    We review recent theoretical developments relevant to heavy-ion experiments carried out within the Beam Energy Scan program at the Relativistic Heavy Ion Collider. Our main focus is on the description of the dynamics of systems created in heavy-ion collisions and establishing the necessary connection between the experimental observables and the QCD phase diagram.

    ↳ nucl-thhep-exhep-phnucl-exIJMPE(2024)·93 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.