Thu·Dec 7, 2023Thursday·December 7, 2023

1. 01*

   Relic neutrino decay solution to the excess radio background

   P.S.Bhupal Dev🇺🇸 · Pasquale Di Bari🇬🇧 · Ivan Martínez-Soler🇬🇧 · Rishav Roshan🇬🇧

   The excess radio background detected by ARCADE 2 represents a puzzle within the standard cosmological model. There is no clear viable astrophysical solution, and therefore, it might indicate the presence of new physics. Radiative decays of a relic neutrino ${\nu }_i$ (either $i=1$, or $i=2$, or $i=3$) into a sterile neutrino ${\nu }_{\mathrm{s}}$, assumed to be quasi-degenerate, provide a solution that currently evades all constraints posed by different cosmological observations and reproduces very well the ARCADE 2 data. We find a very good fit to the ARCADE 2 data with best fit values ${\tau }_i=1.46\times 10^{21}\mathrm{s}$ and $\Delta m_i=4.0\times 10^{-5}\mathrm{eV}$, where ${\tau }_i$ is the lifetime and $\Delta m_i$ is the mass difference between the decaying active neutrino and the sterile neutrino. On the other hand, if relic neutrino decays do not explain ARCADE 2 data, then these place a stringent constraint $\Delta m_i^{3/2}{\tau }_i\gtrsim 2\times 10^{14}{\mathrm{eV}}^{3/2}\mathrm{s}$ in the range $1.4\times 10^{-5}\mathrm{eV}<\Delta m_i<2.5\times 10^{-4}\mathrm{eV}$. The solution also predicts a stronger 21 cm absorption global signal than the predicted one from the $\Lambda$CDM model, with a contrast brightness temperature $T_{21}=-238_{-20}^{+21}\mathrm{mK}$ ($99\%$ C.L.) at redshift $z\simeq 17$. This is in mild tension with the even stronger signal found by the EDGES collaboration, $T_{21}=-500_{-500}^{+200}\mathrm{mK}$, suggesting that this might have been overestimated, possibly receiving a contribution from some unidentified foreground source.

   hep-phastro-ph.COhep-thJCAP(2024)·16 citations
2. 02*

   Implications of Gamma Ray Burst GRB221009A for Extra Dimensions

   Janus Capellan Aban🇹🇼 · Chuan-Ren Chen🇹🇼 · Yuan-Feng Hsieh🇹🇼 · Chrisna Setyo Nugroho🇹🇼

   Anomalous high energy photons, known as GRB221009A, with 18 TeV and 251 TeV were observed by LHAASO and Carpet-2 recently. Such observation of high energy gamma-ray bursts from distant source causes a mystery since high energy photons suffer severe attenuation before reaching the earth. One possibility is the existence of axion-like particles (ALP), and high energy photons at the source can convert to these ALPs which travel intergalactically. In this paper, we study the effects of extra dimensions on the conversion probability between photon and ALPs. The conversion probability saturates and may reach almost $100\%$ for high energy photons. We show that the size of extra dimension affects the energy at which saturation occurs. The observations of high-energy photons may support the possibility of smaller extra dimension.

   hep-phPLB(2024)·1 citation
3. 03*

   Probing CP Violation in Dark Sector through the Electron Electric Dipole Moment

   Jia Liu🇨🇳 · Yuichiro Nakai🇨🇳 · Yoshihiro Shigekami🇨🇳 · Muyuan Song🇨🇳

   The Two Higgs Doublet Model (2HDM) stands as a promising framework for exploring physics beyond the Standard Model (SM). Within this context, we explore the possibility that the two Higgs doublets may serve as a window into CP-violating dark sectors, neutral under the SM gauge groups. Specifically, our focus is on investigating the electric dipole moment (EDM) of the electron, generated solely by CP violation in the dark sector. We present a general formula for the electron EDM, without specifying the structure of the dark sectors, and discuss the current constraints on various dark sector models. It is noteworthy that even in the case of a CP-conserving 2HDM, the resulting electron EDM is capable of reaching the current experimental limit, with CP violation arising exclusively from the dark sectors. Furthermore, we introduce a heavy dark sector (HDS) approximation for the analytic calculation of the EDM, assuming that the dark sector particles are much heavier than the physical states in the 2HDM. This approximation yields simplified analytic results that are consistent with the full numerical calculations.

   hep-phhep-exJHEP(2024)·3 citations
4. 04*

   Gravitational Wave as a Probe of Light Feebly Interacting Dark Matter

   Yuchao Gu🇨🇳 · Liangliang Su🇨🇳 · Lei Wu🇨🇳 · Yongcheng Wu🇨🇳 · Bin Zhu🇨🇳

   Light feebly interacting dark matter is widely predicted in a plethora of new physics models. However, due to very feeble couplings with the Standard Model particles, its relic density produced via the relativistic thermal freeze-out process easily exceeds the observed value. The entropy dilution in an early matter-dominated era provides an attractive mechanism for solving such an overabundance problem. In this work, we note that this dark matter dilution mechanism will lead to two distinctive kinks in the primordial GW spectrum, whose frequencies strongly correlate with the DM mass. We show that the GW detectors, such as Cosmic Explorer (CE) and Big Bang Observer (BBO), can measure the kinks in the primordial GW spectrum and will offer a new avenue to probe light feebly interacting dark matter.

   hep-phPRD(2024)·4 citations
5. 05*

   Quark-versus-gluon tagging in CMS Open Data with CWoLa and TopicFlow

   Matthew J. Dolan🇦🇺 · John Gargalionis🇪🇸 · Ayodele Ore🇩🇪

   We use the CMS Open Data to examine the performance of weakly-supervised learning for tagging quark and gluon jets at the LHC. We target $Z$+jet and dijet events as respective quark- and gluon-enriched mixtures and derive samples both from data taken in 2011 at 7 TeV, and from Monte Carlo. CWoLa and TopicFlow models are trained on real data and compared to fully-supervised classifiers trained on simulation. In order to obtain estimates for the discrimination power in real data, we consider three different estimates of the quark/gluon mixture fractions in the data. Compared to when the models are evaluated on simulation, we find reversed rankings for the fully- and weakly-supervised approaches. Further, these rankings based on data are robust to the estimate of the mixture fraction in the test set. Finally, we use TopicFlow to smooth statistical fluctuations in the small testing set, and to provide uncertainty on the performance in real data.

   hep-phJHEP(2025)·13 citations
6. 06*

   The recursive structure of Baikov representations II: the top-down reduction with intersection theory

   Xuhang Jiang🇨🇳 · Ming Lian🇨🇳 · Li Lin Yang🇨🇳

   Following our previous study of the recursive structure of Baikov representations, we discuss its application in the integration-by-parts reduction of Feynman integrals. We combine the top-down reduction approach with the recursive structure, which can greatly simplify the calculation for each sector in many cases. We introduce a new concept called the top-sector ISP reduction, which generalizes the maximal-cut reduction by retaining the sub-sector information. After subtracting the top-sector components, we provide a general method to transform the remaining integrand explicitly to sub-sectors, such that the reduction procedure can be carried out recursively. In this work, we use the intersection theory to demonstrate our method, although it can be applied to any implementation of the integration-by-parts reduction.

   hep-phPRD(2024)·13 citations
7. 07*

   Probing exotic $J^{PC}$ resonances from deeply bound charmoniumlike molecules: Insights for identifying exotic hadrons

   Zhi-Peng Wang🇨🇳 · Fu-Lai Wang🇨🇳 · Guang-Juan Wang🇯🇵 · Xiang Liu🇨🇳

   We investigate the resonance phenomenon in deeply bound charmoniumlike states. By interpreting the $Y(4220)$, $Y(4360)$, and $\psi (4415)$ states as deeply $S$-wave bound $D{\bar{D}}_1$, $D^{\ast }{\bar{D}}_1$, and $D^{\ast }{\bar{D}}_2^{\ast }$ molecules, respectively, we robustly predict the existence of $4$ $S$-wave deeply bound $C$-parity partner states and $13$ $P$-wave charmoniumlike molecular resonances. These states, formed by exchanging the light mesons and pinpointed through the complex scaling method, include $3$ $S$-wave bound states with exotic quantum numbers $I(J^{PC})$= $0(1^{-+})$ and $5$ $P$-wave resonances with exotic $0(0^{-+})$ and $0(2^{+-})$. We expect future experiments to search for such exotic molecular resonances, which will not only enrich the ongoing construction of ``Particle Zoo 2.0" but also help to scrutinize the hadronic molecular assignments of the $Y$-family particles including the $Y(4220)$, $Y(4360)$, and $\psi (4415)$ states.

   hep-phPRD(2024)·12 citations
8. 08*

   Axion and Dark Fermion Electromagnetic Form Factors in Superfluid He-4

   Wei Chao🇨🇳 · Sichun Sun🇨🇳 · Xin Wang🇨🇳 · Chen-Hui Xie🇨🇳

   Condensed matter materials have shown great potential in searching for light dark matter (DM) via detecting the phonon or magnon signals induced by the scattering of DMs off the materials. In this paper, we study the possibility of detecting electromagnetic form factors of fermionic DM and axion-like particles (ALPs) using superfluid Helium-4. The phonon induced by a sub-GeV fermionic DM scattering off the superfluid can be described using the effective field theory with the interaction between DM and the bulk ${}^4$He. Signals arising from the electromagnetic form factors of light DM in the presence of an external electric field are calculated. Projected constraints on the charge radius, the anapole moment, and the magnetic moment of the DM are derived with 1 kg$\cdot$year exposure. The phonon signal induced by the scattering of ALPs off the superfluid is also calculated, which can put competitive and the first direct detection bounds on ALP-photon-dark photon couplings in the projected experiments.

   hep-phhep-exPRD(2024)·4 citations
9. 09*

   Momentum anisotropy generation in a hybrid approach

   Niklas Götz🇩🇪 · Lucas Constantin🇩🇪 · Hannah Elfner🇩🇪

   Anisotropic flow emerges in all three of hybrid approaches: initial conditions, viscous relativistic hydrodynamics as well as hadronic transport. Previous works focus mainly on a constant or temperature dependent shear viscosity $\eta /s$. Here instead, we study qualitatively the effect of a generalized $\eta /s(T,{\mu }_B)$ in the hybrid approach SMASH-vHLLE-hybrid. The parameterization takes into account the constraints of matching to the transport coefficients in the hadronic phase, as well as of recent Bayesian analysis results. We compare the effect of the different parameterizations in the intermediate energy region of $\sqrt{s_{NN}}$=7.7 - 39.0 GeV. We observe that using the energy density dependent parameterization decreases the effect of the point of particlization. In addition, we quantify the uncertainty due to different initial state profiles, including the SMASH initial conditions as well as TrENTo and IP-Glasma profiles. It can be shown that the initial state transverse momentum impacts final state momentum anisotropy.

   hep-phnucl-exnucl-th0 citations
10. 10*

    Charged pion production in the annihilation reactions $e^{+}+e^{-}\to p+\bar{n}+{\pi }^{-}$ and $e^{+}+e^{-}\to n+\bar{p}+{\pi }^{+}$

    G. I. Gakh🇺🇦 · M.I. Konchatnij🇺🇦 · N.P. Merenkov🇺🇦 · E. Tomasi-Gustafsson🇫🇷

    The nonresonant mechanism in the reactions $e^{+}{e}^{-}\to {\pi }^{-}p\bar{n}$ and $e^{+}{e}^{-}\to {\pi }^{+}n\bar{p}$ is investigated in frame of the one-photon exchange approximation. The description of the hadronic phase space and the invariant amplitude formalism, earlier developed for the neutral pion channel, are applied here. Some modifications are required to fulfill the invariance and to account for an additional contribution due to diagram with the pion pole. Two different variants which lead to dipole and monopole asymptotic behaviour of the pion electromagnetic form factor, are considered. The double and single distributions over the invariant variables as well the total cross section, are obtained. The results are plotted for $s=$5,\,6,\,10,\,16\, GeV${}^2$. The calculations are performed for the ${\pi }^{-}p\bar{n}$ channel and the rules to proceed to the ${\pi }^{+}n\bar{p}$ channel are formulated for every distribution.

    hep-phnucl-th0 citations
11. 11*

    SU($2$) string tension in the continuum limit using an effective theory of center vortices

    Zahra Asmaee🇮🇷 · Motahareh Kiamari🇮🇷 · Sedigheh Deldar🇮🇷

    Using an effective theory for an ensemble of center vortices, we observe the area law fall-off in the continuum limit for the SU($2$) gauge group in three-dimensional Euclidean space-time. The string tension is obtained in terms of the intrinsic properties of the vortices and a parameter which describes their interactions. In addition, fitting our analytical results on lattice data, we show that the repulsive force between the vortices increases with temperature. This behavior is expected due to the reduction of vortex configuration at higher temperatures, required for the deconfinement regime.

    hep-phhep-lat0 citations
12. 12*

    p-adic reconstruction of rational functions in multi-loop amplitudes

    Herschel A. Chawdhry🇺🇸

    Numerical reconstruction techniques are widely employed in the calculation of multi-loop scattering amplitudes. In recent years, it has been observed that the rational functions in multi-loop calculations greatly simplify under partial fractioning. In this article, we present a technique to reconstruct rational functions directly in partial-fractioned form, by evaluating the functions at special integer points chosen for their properties under a p-adic metric. As an application, we apply this technique to reconstruct the largest rational function in the integration-by-parts reduction of one of the rank-5 integrals appearing in 2-loop 5-point full-colour massless amplitude calculations in Quantum Chromodynamics (QCD). The number of required numerical probes (per prime field) is found to be around 25 times smaller than in conventional techniques, and the obtained result is 130 times smaller. The reconstructed result displays signs of additional structure that could be used to further reduce its size and the number of required probes.

    hep-phhep-thPRD(2024)·26 citations
13. 13*

    Revisiting the averaged annihilation rate of thermal relics at low temperature

    A. Arbey🇫🇷 · F. Mahmoudi🇫🇷 · M. Palmiotto🇫🇷

    We derive a low-temperature expansion of the formula to compute the average annihilation rate $⟨\sigma v⟩$ for dark matter in ${\mathbb{Z}}_2$-symmetric models, both in the absence and the presence of mass degeneracy in the spectrum near the dark matter candidate. We show that the result obtained in the absence of mass degeneracy is compatible with the analytic formulae in the literature, and that it has a better numerical behaviour for low temperatures. We also provide as ancillary files two Wolfram Mathematica notebooks which perform the two expansions at any order.

    hep-phEPJC(2024)·2 citations
14. 14*

    Coulomb-Nuclear Interference in polarized pA scattering

    B. Z. Kopeliovich🇨🇱 · M. Krelina🇨🇿 · I. K. Potashnikova🇨🇱

    We made the first attempt to understand the observed unusual t dependence of single-spin asymmetry observed in the HJET experiment at RHIC. Usually, the interaction of hadrons is presented as a long-range Coulomb interaction and a short-range strong interaction with Coulomb corrections. Such a division gives rise to a Coulomb phase of the hadronic term. Conversely, here we consider short-range hadronic interaction as a correction to the long-range electromagnetic term, i.e., we treat it as an absorptive correction. This significantly affects the Coulomb-nuclear interference, which is a source of single-spin azimuthal asymmetry at small angles.

    hep-phUniverse(2024)·6 citations
15. 15*

    Primary Observables for Electroweak Gauge Boson Collider Signals

    Cristien Arzate🇺🇸 · Spencer Chang🇺🇸 · Gabriel Jacobo🇺🇸

    In this paper, we determine a basis for the on-shell 4-point amplitudes $VVVV$ for Standard Model gauge bosons $V=W^{\pm },Z,\gamma ,g$. Following previous work, this completes the analysis of 3- and 4-point amplitudes for the Standard Model and could be used for model independent searches for beyond the Standard Model physics at colliders. Our results include a Lagrangian parametrization for the "primary" amplitudes, where including additional derivatives leads to the Mandelstam "descendant" amplitudes, and upper bounds on the coupling constants from imposing unitarity. We also perform an estimate for the sensitivity for new $Z$ decays at the HL-LHC, finding that $Z\to \gamma \bar{\ell }\ell$ could be searched for, but that other decay modes, like $Z\to (\gamma \gamma \gamma ,\gamma gg)$, are too small to be discovered after imposing unitarity constraints.

    hep-phhep-exhep-thPRD(2024)·5 citations
16. 16*

    A Duet of Freeze-in and Freeze-out: Lepton-Flavored Dark Matter and Muon Colliders

    Pouya Asadi🇺🇸 · Aria Radick🇺🇸 · Tien-Tien Yu🇺🇸

    We study a Lepton-Flavored Dark Matter model and its signatures at a future Muon Collider. We focus on the less-explored regime of feeble dark matter interactions, which suppresses the dangerous lepton-flavor violating processes, gives rise to dark matter freeze-in production, and leads to long-lived particle signatures at colliders. We find that the interplay of dark matter freeze-in and its mediator freeze-out gives rise to an upper bound of around TeV scales on the dark matter mass. The signatures of this model depend on the lifetime of the mediator, and can range from generic prompt decays to more exotic long-lived particle signals. In the prompt region, we calculate the signal yield, study useful kinematics cuts, and report tolerable systematics that would allow for a $5\sigma$ discovery. In the long-lived region, we calculate the number of charged tracks and displaced lepton signals of our model in different parts of the detector, and uncover kinematic features that can be used for background rejection. We show that, unlike in hadron colliders, multiple production channels contribute significantly which leads to sharply distinct kinematics for electroweakly-charged long-lived particle signals. Ultimately, the collider signatures of this lepton-flavored dark matter model are common amongst models of electroweak-charged new physics, rendering this model a useful and broadly applicable benchmark model for future Muon Collider studies that can help inform work on detector design and studies of systematics.

    hep-phhep-exPRD(2024)·20 citations
17. 17*

    Axion Electrodyanmics in the Presence of Current Sources

    Joshua Berger🇺🇸 · Amit Bhoonah🇺🇸

    Axions are among the most sought-after candidates for dark matter. In the ultralight regime, they could help alleviate puzzles in small scale cosmology. Searches for a halo of axion dark matter rely on the electromagnetic response to a magnetic field. In this work, we resolve a number of issues in the determination of this response by carefully solving Maxwell's equations in the presence of an axion background. We find that the electric field induced by a magnetic field in an axion background is significant and unsuppressed by the size of the experiment.

    hep-ph1 citation
18. 18*

    Boundaries of Universal Theories

    Matthew McCullough🇨🇭 · Lorenzo Ricci🇺🇸 · Marc Riembau🇨🇭

    Universal theories are a broad class of well-motivated microscopic dynamics of the electroweak sector that go beyond the Standard Model description. The long distance physics is described by electroweak parameters which correspond to local operators in the Effective Field Theory. We show how unitarity and analyticity constrain the space of parameters. In particular, the $W$ and $Y$ parameters are constrained to be positive and are necessarily the leading terms in the low energy expansion. We assess the impact of unitarity on the interpretation of Drell-Yan data. In passing, we uncover an unexpected Wilson coefficient transcendental cancellation at the $\mathcal{O}(<10^{-3})$ level.

    hep-phhep-thPRD(2025)·13 citations
19. 19*

    Sub-GeV millicharge dark matter from the $U(1{)}_X$ hidden sector

    Wan-Zhe Feng🇨🇳 · Zi-Hui Zhang🇨🇳 · Kai-Yu Zhang🇨🇳

    We conduct a comprehensive study on the sub-GeV millicharge dark matter produced through the freeze-in mechanism. We discuss in general the mixing mechanism, encompassing both kinetic mixing and mass mixing, between the $U(1{)}_X$ hidden sector and the standard model, which can generate millicharge carried by the dark fermions from the hidden sector. We discuss in depth how such millicharge is generated, and clarify several misunderstandings regarding this subject in the literature. Without employing an effective field theory approach, where the photon field directly mixed with the additional $U(1)$, we analyze a general renormalizable model and investigate the complete evolution of the hidden sector particles. Due to the substantial self-interactions among hidden sector particles, the evolution of the hidden sector temperature plays a crucial role, which is addressed concurrently with the number densities of hidden sector particles by solving a set of coupled Boltzmann equations. We thoroughly examine eight benchmark models from six distinct cases. Some of our key findings from the analysis of these benchmark models may be generalizable and applicable to broader freeze-in scenarios. We also explore the possibility that the $\mathcal{O}$(keV) $U(1{)}_X$ dark photon is a viable dark matter candidate, even though it can contribute at most $\sim 5\%$ to the total observed dark matter relic density.

    hep-phJCAP(2024)·12 citations
20. 20*

    Entanglement in massive Schwinger model at finite temperature and density

    Sebastian Grieninger🇺🇸 · Kazuki Ikeda🇺🇸 · Dmitri E. Kharzeev🇺🇸 · Ismail Zahed🇺🇸

    We evaluate the entanglement entropy and entropic function of massive two dimensional QED (Schwinger model) at finite temperature, density, and $\theta$-angle. In the strong coupling regime, the entropic function is dominated by the boson mass for large spatial intervals, and reduces to the CFT result for small spatial intervals. We also discuss the entanglement spectrum at finite temperature and a finite $\theta$-angle.

    ↳ hep-thhep-phnucl-thPRD(2024)·21 citations
21. 21*

    Kaluza-Klein tower and bubble nucleation in six dimensional Einstein-Maxwell theory

    Min-Seok Seo🇰🇷

    We study the implication of the distance and the cobordism conjecture on the 6-dimensional Einstein-Maxwell theory compactified on $S^2$. In this toy model, the radion potential is stabilized by the conspiracy of the curvature of $S^2$ and the flux through $S^2$ parametrized by $f$, and uplifted by the positive 6-dimensional cosmological constant parametrized by $\lambda$. When $\lambda =0$, the radion is stabilized at the anti-de Sitter (AdS) vacuum, which cannot be interpolated to the Minkowski vacuum since the Kaluza-Klein (KK) tower descends from UV in the vanishing limit of the 4-dimensional cosmological constant. For nonzero $\lambda$ which realizes the metastable de Sitter (dS) vacuum, as well as the AdS and the Minkowski vacuum, such an obstruction can be found provided the combination $f^2\lambda$ is fixed and the limit $\lambda \to 0$ is taken. Moreover, the 6-dimensional Einstein-Maxwell theory allows the transition between vacua through the nucleation of the bubble. In this case, the values of the 4-dimensional cosmological constant inside and outside the bubble are different as $f$ is changed at the bubble wall, while $\lambda$ remains unchanged. Regarding the AdS vacuum with the vanishing curvature radius as the `nothing', we find that the transition from the metastable dS vacuum to the nothing is not prevented by the descent of the KK tower since $f^2\lambda$ is not fixed.

    ↳ hep-thhep-phEPJC(2024)·3 citations
22. 22*

    Can we distinguish black holes with electric and magnetic charges from quasinormal modes?

    Antonio De Felice🇯🇵 · Shinji Tsujikawa🇯🇵

    We compute the quasinormal modes of static and spherically symmetric black holes (BHs) with electric and magnetic charges. For the electrically charged case, the dynamics of perturbations separates into the odd- and even-parity sectors with two coupled differential equations in each sector. In the presence of both electric and magnetic charges, the differential equations of four dynamical degrees of freedom are coupled with each other between odd- and even-parity perturbations. Despite this notable modification, we show that, for a given total charge and mass, a BH with mixed electric and magnetic charges gives rise to the same quasinormal frequencies for fundamental modes. This includes the case in which two BHs have equal electric and magnetic charges for each of them. Thus, the gravitational-wave observations of quasinormal modes during the ringdown phase alone do not distinguish between electrically and magnetically charged BHs.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2024)·16 citations
23. 23*

    Successful $\nu p$-process in neutrino-driven outflows in core-collapse supernovae

    Alexander Friedland🇺🇸 · Payel Mukhopadhyay🇺🇸 · Amol V. Patwardhan🇺🇸

    The origin of the solar system abundances of several proton-rich isotopes, especially ${}^{92,94}$Mo and ${}^{96,98}$Ru, has been an enduring mystery in nuclear astrophysics. An attractive proposal to solve this problem is the $\nu p$-process, which can operate in neutrino-driven outflows in a core-collapse supernova after the shock is launched. Years of detailed studies, however, have cast doubt over the ability of this process to generate sufficiently high absolute and relative amounts of various $p$-nuclei. The $\nu p$-process is also thought to be excluded by arguments based on the long-lived radionuclide ${}^{92}$Nb.Here, we present explicit calculations, in which both the abundance ratios and the absolute yields of the $p$-nuclei up to $A\lesssim 105$ are successfully reproduced, even when using the modern (medium enhanced) triple-$\alpha$ reaction rates. The process is also shown to produce the necessary amounts of ${}^{92}$Nb. The models are characterized by subsonic outflows and by the protoneutron star masses in the $\gtrsim 1.7M_{\odot }$ range. This suggests that the Mo and Ru $p$-nuclides observed in the Solar System were made in CCSN explosions characterized by an extended accretion stage.

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-thJCAP(2025)·8 citations
24. 24*

    Speed of Sound in Magnetized Nuclear Matter

    Rajkumar Mondal🇮🇳 · Nilanjan Chaudhuri🇮🇳 · Pradip Roy🇮🇳 · Sourav Sarkar🇮🇳

    Employing the non-linear Walecka model we investigate the characteristics of nuclear matter under the influence of a background magnetic field at a finite temperature and baryon chemical potential. In the presence of the magnetic field the spinodal lines and the critical end point (CEP) undergo changes in the $T-{\mu }_B$ plane. The squared speed of sound exhibits anisotropic behavior, dividing into parallel and perpendicular components. Additionally, the presence of a magnetic field induces anisotropy in the isothermal compressibility. It is found that the parallel component is smaller than the perpendicular one for all values of temperature, chemical potential and magnetic field indicating that the equation of state is stiffer along the magnetic field direction.

    ↳ nucl-thhep-phPRC(2024)·10 citations
25. 25*

    Higher order dynamical charge fluctuations in heavy-ion collisions

    Bhanu Sharma🇮🇳 · P. K. Sahu🇮🇳

    The event-by-event charge fluctuation measurements are proposed to provide the signature of quark-gluon plasma (QGP) in heavy-ion collisions. Measure of dynamical charge fluctuations is expected to carry information of initial fractional charge of the QGP phase at the final state. We propose the higher order charge fluctuation measurement to study the QGP signal in heavy-ion collisions. This higher order charge fluctuation observable can amplify the signature of QGP. Also, the SMASH model is used to study the behavior of these observable in heavy-ion collisions at center of mass energies accessible in the STAR beam energy scan program.

    ↳ nucl-thhep-exhep-phnucl-ex1 citation
26. 26*

    Gravitational wave double copy of radiation from gluon shockwave collisions

    Himanshu Raj🇺🇸 · Raju Venugopalan🇺🇸

    In a recent paper, we showed that the gravitational wave spectrum from trans-Planckian shockwave scattering in Einstein gravity is determined by the gravitational Lipatov vertex expressed as the bilinear double copy ${\Gamma }^{\mu \nu }=\frac{1}{2}{C}^{\mu }{C}^{\nu }-\frac{1}{2}{N}^{\mu }{N}^{\nu }$ where $C^{\mu }$ is the QCD Lipatov vertex and $N^{\mu }$ is the QED soft photon factor. We show here that this result can be directly obtained by careful application of the classical color-kinematic duality to the spectrum obtained in gluon shockwave collisions.

    ↳ hep-thgr-qchep-phnucl-thPLB(2024)·9 citations
27. 27*

    Higgs self-coupling measurements at the FCC-hh

    Birgit Stapf🇩🇪 · Angela Taliercio🇺🇸 · Elisabetta Gallo🇩🇪 · Kerstin Tackmann🇩🇪 · Paola Mastrapasqua🇧🇪

    The hadron collider phase of the Future Circular Collider (FCC-hh) is a proton-proton collider operating at a center-of-mass energy of 100 TeV. It is one of the most ambitious projects planned for the rest of this century and offers ample opportunities in the hunt for new physics, both through its direct detection reach as well as through indirect evidence from precision measurements. Extracting a precision measurement of the Higgs self-coupling from the Higgs pair production cross-section will play a key role in our understanding of electroweak symmetry breaking, as the self-coupling gives insight into the nature of the Higgs potential. With the large data set of in total 30 ${\text{ab}}^{-1}$ which is envisioned to be collected during the FCC-hh runtime the Higgs self-coupling will be determined down to the percent level. This paper presents prospect studies for Higgs self-coupling measurements in the $b\bar{b}\gamma \gamma$ and $b\bar{b}\ell \ell +E_{\text{T}}^{\text{miss}}$ final states, with the combined, expected precision on the Higgs self-coupling modifier ${\kappa }_{\lambda }$ reaching 3.2-5.7% at 68% confidence level, assuming all other Higgs couplings follow their Standard Model expectations and depending on the systematic uncertainties assumed. This high precision is mostly driven by the $b\bar{b}\gamma \gamma$ final state analysis, while the $b\bar{b}\ell \ell +E_{\text{T}}^{\text{miss}}$ final state - newly studied for its FCC-hh prospects in this document - on its own reaches a maximum precision of roughly 20% on ${\kappa }_{\lambda }$.

    ↳ hep-exhep-phPoS(2024)·4 citations
28. 28*

    Analytical solutions for quantum radiation reaction in high-intensity lasers

    T. G. Blackburn🇸🇪

    While the Landau-Lifshitz equation, which describes classical radiation reaction, can be solved exactly and analytically for a charged particle accelerated by a plane electromagnetic wave, no such solutions are available for quantum radiation reaction (the recoil arising from the successive, incoherent emission of hard photons). Yet upcoming experiments with ultrarelativistic electron beams and high-intensity lasers will explore the regime where both radiation-reaction and quantum effects are important. Here we present analytical solutions for the mean and variance of the energy distribution of an electron beam that collides with a pulsed plane electromagnetic wave, which are obtained by means of a perturbative expansion in the quantum parameter ${\chi }_0$. These solutions capture both the quantum reduction in the radiated power and stochastic broadening, and are shown to be accurate across the range of experimentally relevant collision parameters, i.e. GeV-class electron beams and laser amplitudes $a_0\lesssim 200$.

    ↳ physics.plasm-phhep-phPRA(2024)·8 citations
29. 29*

    Extracting the Asymptotic Behavior of S-matrix Elements from their Phases

    Ira Z. Rothstein🇺🇸 · Michael Saavedra🇺🇸

    The asymptotic kinematic limits of S-matrices are dominated by large logarithms which, roughly speaking, fall into two categories: those which are controlled by a renormalization group (RG) scale, which we may think of as logs involving ratios of invariant mass scales, and those which are functions of ratios of rapidities, so called "rapidity logs". It has been pointed out by Caron-Huot and Wilhlem [1] that RG anomalous dimension can be extracted from the phase of the S-matrix, which can greatly simplify calculations via unitarity methods. In this paper we generalize the results of [1] to show that the phase can be used to reconstruct rapidity anomalous dimensions, by performing a complex boost. The methodology introduced here also allows one to calculate without the need for a rapidity regulator. We demonstrate the use of this method to derive the rapidity anomalous dimensions in the Sudakov form factor, the two parton soft function and the Regge trajectory in QCD.

    ↳ hep-thhep-phnucl-thJHEP(2024)·11 citations
30. 30*

    Quantum reference frames, revisited

    Matthew J. Lake🇩🇪 · Marek Miller🇩🇰

    The topic of quantum reference frames (QRFs) has attracted a great deal of attention in the recent literature. Potentially, the correct description of such frames is important for both the technological applications of quantum mechanics and for its foundations, including the search for a future theory of quantum gravity. In this letter, we point out potential inconsistencies in the mainstream approach to this subject and propose an alternative definition that avoids these problems. Crucially, we reject the notion that transformations between QRFs can be represented by unitary operators and explain the clear physical reasons for this. An experimental protocol, capable of empirically distinguishing between competing definitions of the term, is also proposed. The implications of the new model, for uncertainty relations, spacetime symmetries, gauge symmetries, the quantisation of gravity, and other foundational issues are discussed, and possible directions for future work in this field are considered.

    ↳ gr-qchep-phquant-ph15 citations
31. 31*

    Perturbing Fast Neutrino Flavor Conversion

    Marie Cornelius🇩🇰 · Shashank Shalgar🇩🇰 · Irene Tamborra🇩🇰

    The flavor evolution of neutrinos in dense astrophysical sources, such as core-collapse supernovae or compact binary mergers, is non-linear due to the coherent forward scattering of neutrinos among themselves. Recent work in this context has been addressed to figure out whether flavor equipartition could be a generic flavor outcome of fast flavor conversion. We investigate the flavor conversion physics injecting random perturbations in the neutrino field in two simulation setups: 1. a spherically symmetric simulation shell without periodic boundaries, with angular distributions evolving dynamically thanks to non-forward scatterings of neutrinos with the background medium, and neutrino advection; 2. a periodic simulation shell, with angular distributions of neutrinos defined a priori and neutrino advection. We find that, independent of the exact initial flavor configuration and type of perturbations, flavor equipartition is generally achieved in the system with periodic boundaries; in this case, perturbations aid the diffusion of flavor structures to smaller and smaller scales. However, flavor equipartition is not a general outcome in the simulation shell without periodic boundaries, where the inhomogeneities induced perturbing the neutrino field affect the flavor evolution, but do not facilitate the diffusion of flavor waves. This work highlights the importance of the choice of the simulation boundary conditions in the exploration of fast flavor conversion physics.

    ↳ astro-ph.HEhep-phJCAP(2024)·30 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.