Mon·Feb 3, 2025Monday·February 3, 2025

1. 01*

   $CP$ violation in the $HZZ$ vertex and left-right asymmetries

   A. I. Hernández-Juárez🇲🇽 · R. Gaitán🇲🇽

   We investigate new contributions to the $HZZ$ vertex from the Flavor Changing Neutral Current (FCNC) involving the Higgs and $Z$ bosons. Our calculations reveal that the form factors $h_2^V$ and $h_3^V$ ($V=H$, $Z$) can be induced through these couplings, and we present our results in terms of the Passarino-Veltman scalar functions. Using the current limits on $H\overline{t}c$ and $Z\overline{t}c$ couplings, we determine that the new contributions to the $CP$-conserving form factor $h_2^V$ are small compared to the Standard Model (SM) predictions. However, for the $CP$-violating form factor $h_3^V$, the contributions can reach values as high as $10^{-6}$, five orders of magnitude larger than in the SM. Furthermore, we examine how these results influence the left-right asymmetries in the processes $H^{\ast }\to ZZ$ and $Z^{\ast }\to ZH$. Our findings suggest that significant deviations from SM predictions may occur when considering FCNC contributions.

   hep-phPRD(2025)·4 citations
2. 02*

   Quasi-Two-Body $B\to P(K^{+}{K}^{-},{\pi }^{+}{\pi }^{-})$ Decays with $f_0(980)$ Resonance

   Ya-Xin Wang🇨🇳 · Jun-Peng Wang🇨🇳 · Ying Li🇨🇳 · Zhi-Tian Zou🇨🇳

   In this study, we investigate the $CP$-averaged branching fractions and direct $CP$ asymmetries in the quasi-two-body decays $B\to P(f_0(980)\to )(K^{+}{K}^{-},{\pi }^{+}{\pi }^{-})$ within the framework of perturbative QCD approach, where $P$ denotes light pseudoscalar mesons ($\pi$,$K$). The timelike form factor $F_S(\omega )$, characterizing final-state interactions between collinear particles in the resonant region, is modeled through the revised relativistic Breit-Wigner formalism for the $S$-wave $f_0(980)$ resonance. Within the Gegenbauer moments of the $S$-wave two-meson distribution amplitudes constrained by current data, we predict the branching fractions of $B\to P(f_0(980)\to )(K^{+}{K}^{-},{\pi }^{+}{\pi }^{-})$ to lie in the range of $10^{-8}$ to $10^{-6}$. Our calculations reveal that our theoretical results for some decay modes exhibit satisfactory agreement with existing measurements from the BaBar and Belle collaborations. Furthermore, we extract the corresponding branching fractions of $B\to P{f}_0(980)$ decays from the quasi-two-body counterparts $B\to P(f_0(980)\to ){\pi }^{+}{\pi }^{-}$ rather than $B\to P(f_0(980)\to )K^{+}{K}^{-}$. All predictions are awaiting experimental verification in current and upcoming collider experiments.

   hep-phhep-exPRD(2025)·4 citations
3. 03*

   Resummation for Lattice QCD Calculation of Generalized Parton Distributions at Nonzero Skewness

   Jack Holligan🇺🇸 · Huey-Wen Lin🇺🇸 · Rui Zhang🇺🇸 · Yong Zhao🇺🇸

   Large-momentum effective theory (LaMET) provides an approach to directly calculate the $x$-dependence of generalized parton distributions (GPDs) on a Euclidean lattice through power expansion and a perturbative matching. When a parton's momentum becomes soft, the corresponding logarithms in the matching kernel become non-negligible at higher orders of perturbation theory, which requires a resummation. But the resummation for the off-forward matrix elements at nonzero skewness $\xi$ is difficult due to their multi-scale nature. In this work, we demonstrate that these logarithms are important only in the threshold limit, and derive the threshold factorization formula for the quasi-GPDs in LaMET. We then propose an approach to resum all the large logarithms based on the threshold factorization, which is implemented on a GPD model. We demonstrate that the LaMET prediction is reliable for $[-1+x_0,-\xi -x_0]\cup [-\xi +x_0,\xi -x_0]\cup [\xi +x_0,1-x_0]$, where $x_0$ is a cutoff depending on hard parton momenta. Through our numerical tests with the GPD model, we demonstrate that our method is self-consistent and that the inverse matching does not spread the nonperturbative effects or power corrections to the perturbatively calculable regions.

   hep-phhep-latJHEP(2025)·18 citations
4. 04*

   Exploring the DGLAP resummation in the JIMWLK Hamiltonian

   Néstor Armesto🇪🇸 · Alex Kovner🇺🇸 · Víctor López-Pardo🇪🇸

   We explore the recently derived equation that resums DGLAP corrections to the JIMWLK Hamiltonian in the simplified setting of the SU(2) gauge theory. We solve the equation numerically for the scattering matrix of a dressed gluon for a particular initial condition, that corresponds to a dipole initial state. As expected, the $S$-matrix of a single dressed gluon state ceases to be unitary if evolved to significant $\ln Q^2/Q_s^2$. Our numerical results indicate an interesting universal (independent of the coupling constant) pattern for this deviation from unitarity.

   hep-phnucl-thJHEP(2025)·2 citations
5. 05*

   Longitudinal short-distance constraints on hadronic light-by-light scattering and tensor meson contributions to the muon $g-2$

   Jonas Mager🇦🇹 · Luigi Cappiello🇮🇹 · Josef Leutgeb🇦🇹 · Anton Rebhan🇦🇹

   Short-distance constraints from the operator product expansion in QCD play an important role in the evaluation of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. While conventional hadronic models involving a finite number of resonances fail to reproduce the correct power laws implied by them, holographic QCD has been shown to naturally incorporate the Melnikov-Vainshtein constraint on the longitudinal amplitude following from the triangle anomaly in the asymmetric limit, where one photon virtuality remains small compared to the others. This is saturated by an infinite tower of axial vector mesons, and their numerical contribution to the muon $g-2$ in AdS/QCD models agrees rather well with a recent dispersive analysis and alternative approaches. However, the longitudinal short-distance constraint where all virtualities are large turns out to be matched only at the level of 81\%. In this Letter we show that tensor mesons, whose contribution to the muon $g-2$ has recently been found to be underestimated, can fill this gap, because in holographic QCD their infinite tower of excited mesons only contributes to the symmetric longitudinal short-distance constraint. Numerically, they give rise to a sizeable positive contribution from the low-energy region below 1.5 GeV, a small one from the mixed region, and a negligible one from the high-energy region, which could explain the remaining gap between the most recent dispersive and lattice results for the complete hadronic light-by-light contribution.

   hep-phPRL(2025)·22 citations
6. 06*

   Viscous effects of a hot QGP medium in time dependent magnetic field and their phenomenological significance

   Debarshi Dey🇮🇳 · Gowthama K K🇮🇳 · Sadhana Dash🇮🇳 · Basanta Kumar Nandi🇮🇳

   In this work, we have studied, for the first time, the impact of a realistic picture of a time dependent electric and magnetic field on the shear and bulk viscosities of the medium. Both the electric and magnetic fields are considered to be exponentially decaying with time, and the study is valid in the regime where the magnetic field strength is weak ($eB\ll T^2$). The evaluation has been done in the kinetic theory framework wherein we have solved the relativistic Boltzmann transport equation within the relaxation time approximation collision kernel. We have shown that the constant weak field results as well as the $B=0$ results in the literature can be obtained as special cases of our general results. We have observed that the shear and bulk viscosities increase with time or equivalently, decrease with the strength of the magnetic field. To connect these observations with experiments, we have calculated the thermalization time, shear viscosity to entropy ratio ($\eta /s$), and bulk viscosity to entropy ratio ($\zeta /s$).

   hep-phnucl-thPRD(2025)·1 citation
7. 07*

   Spin oscillations of neutrinos scattered by the supermassive black hole in the galactic center

   Mridupawan Deka🇷🇺 · Maxim Dvornikov🇷🇺

   In this work, we study the propagation and spin oscillations of neutrinos in their scattering by a supermassive black hole (SMBH) surrounded by a realistic accretion disk. We review various descriptions of the fermion spin evolution in a curved spacetime under the influence of external fields. The overview of the test particle motion in the gravitational field of a rotating SMBH is also present. The external fields which a neutrino spin interacts with are the electroweak forces in plasma and the toroidal magnetic field in the accretion disk surrounding SMBH. Spin precession of neutrinos, which are supposed to be Dirac particles, is caused by the interaction of the neutrino magnetic moment with the magnetic field in the disk. We use a semi-analytical model of a thick accretion disk and review its characteristics. The cases of co-rotating and counter-rotating disks with respect to BH are discussed. We consider the incoming flux of neutrinos having an arbitrary angle with respect to the BH spin since the recent results of the Event Horizon Telescope indicate that the BH spin in the galactic center is not always perpendicular to the galactic plane. For our study, we consider a large number of incoming test neutrinos. We briefly discuss our results and their applications in the observations of astrophysical neutrinos.

   hep-phastro-ph.HEgr-qcMod.Phys.Lett.A(2025)·2 citations
8. 08*

   Probing Light Particles With Optically Trapped Sensors Through Nucleon Scattering

   Bhaskar Dutta🇺🇸 · Dilip Kumar Ghosh🇮🇳 · Sk Jeesun🇮🇳

   Optically levitated nanospheres are highly sensitive to the motion of their center of mass even under small momentum transfer. We propose detecting exotic particles via nucleon scattering in such spheres in the context of an ongoing experiment. The 200 nm-diameter spheres within the present experimental realization, featuring a configuration of the array $4\times 4$ and its upgrade, can achieve sensitivity to nuclear couplings of ALPs exclusively and pseudoscalar dark matter in the $\sim 10$ keV mass range, targeting previously unconstrained regions of parameter space. In contrast, a smaller sphere with a diameter of 15 nm benefits from overall coherence enhancement, enabling the detection of pseudoscalar and vector dark matter down to $\mathcal{O}(100)$ eV even with a single sphere. This smaller setup also offers the potential for the direct detection of Earth-bound dark matter strongly coupled with visible matter, even with its minimal velocity and tiny fractional abundance.

   hep-phhep-exPRD(2026)·3 citations
9. 09*

   Results on meson-meson scattering at large $N_{\text{c}}$

   Jorge Baeza-Ballesteros🇪🇸 · Pilar Hernández🇪🇸 · Fernando Romero-López🇨🇭

   We present results on the large $N_{\text{c}}$ scaling of meson-meson scattering amplitudes. We work in a theory with $N_{\text{f}}=4$ degenerate quark flavors and run lattice simulations with $N_{\text{c}}=3-6$ and pion mass $M_{\pi }\approx 590$ MeV. We focus on three different scattering channels, two of which have the same quantum numbers as some tetraquark candidates recently found at LHCb. Finite-volume energies are extracted using a large set of operators, containing two-particle operators corresponding to two pions or two vector mesons, and local tetraquark operators. Using Lüscher's quantization condition, we constrain the infinite-volume scattering amplitudes and investigate subleading $N_{\text{c}}$ corrections to the large $N_{\text{c}}$ limit. For one of the channels, we find indications of a virtual bound state at $N_{\text{c}}=3$, which may be related to one of the aforementioned exotic states.

   ↳ hep-lathep-phhep-thPoS(2025)·1 citation
10. 10*

    Temperature-redshift relation in energy-momentum-powered gravity models

    C. J. A. P. Martins🇵🇹 · A. M. M. Vieira

    There has been recent interest in the cosmological consequences of energy-momentum-powered gravity models, in which the matter side of Einstein's equations includes a term proportional to some power, $n$, of the energy-momentum tensor, in addition to the canonical linear term. Previous works have suggested that these models can lead to a recent accelerating universe without a cosmological constant, but they can also be seen as phenomenological extensions of the standard $\Lambda$CDM, which are observationally constrained to be close to the $\Lambda$CDM limit. Here we show that these models violate the temperature-redshift relation, and are therefore further constrained by astrophysical measurements of the cosmic microwave background temperature. We provide joint constraints on these models from the combination of astrophysical and background cosmological data, showing that this power is constrained to be about $|n|<0.01$ and $|n|<0.1$, respectively in models without and with a cosmological constant, and improving previous constraints on this parameter by more than a factor of three. By breaking degeneracies between this parameter and the matter density, constraints on the latter are also improved by a factor of about two.

    ↳ astro-ph.COgr-qchep-phPRD(2025)·2 citations
11. 11*

    Hydrodynamic attractor in periodically driven ultracold quantum gases

    Aleksas Mazeliauskas🇩🇪 · Tilman Enss🇩🇪

    Hydrodynamic attractors are a universal phenomenon of strongly interacting systems that describe the hydrodynamic-like evolution far from local equilibrium. In particular, the rapid hydrodynamization of the Quark-Gluon Plasma is behind the remarkable success of hydrodynamic models of high-energy nuclear collisions. So far, hydrodynamic attractors have been explored only in systems undergoing monotonic expansion, such as Bjorken flow. We demonstrate that a system with an oscillating isotropic expansion exhibits a novel cyclic attractor behavior. This phenomenon can be investigated in ultracold quantum gases with externally modulated scattering length, offering a new avenue for experimentally discovering hydrodynamic attractors.

    ↳ cond-mat.quant-gashep-phnucl-thPRL(2026)·9 citations
12. 12*

    Study on the $P$-wave form factors contributing to $B_s$ to $D_s$ inclusive semileptonic decays from lattice simulations

    Zhi Hu🇯🇵 · Alessandro. Barone🇩🇪 · Ahmed Elgaziari🇬🇧 · Shoji Hashimoto🇯🇵 · Andreas Jüttner🇬🇧 · Takashi Kaneko🇯🇵 · Ryan Kellermann🇯🇵

    We present a pilot study on extracting the form factors of the semileptonic decay of a $B_s$ meson to the $P$-wave $D_s^{\ast \ast }$ states from $B_s$ four-point correlators. With their inclusive nature, four-point correlators include contributions from all possible final states. From the extracted $P$-wave form factors, we obtain numerical results for the corresponding Isgur-Wise form factors. The results suggest significant contributions from radial excitations to the Uraltsev sum rule at zero-recoil. In this pilot study, a coarse lattice of $24^3\times 64$ with lattice spacing of $0.11\mathrm{fm}$ is used for the analysis.

    ↳ hep-lathep-phPoS(2025)·5 citations
13. 13*

    Various constraints on BSM physics from extensive air showers and from ultra-high energy gamma-ray and neutrino searches

    O. Deligny🇫🇷

    Various phenomena of physics beyond that of the Standard Model could occur at high scale. Ultra-high energy cosmic rays are the only particles available to explore scales above a few dozens of TeV. Although these explorations are much more limited than those carried out with colliders, they provide a series of constraints in several topics such as tests of Lorentz invariance, dark matter, phase transitions in the early universe or sterile neutrinos. Several of these constraints are reviewed in these proceedings of UHECR2024 based on searches for anomalous characteristics in extensive air showers or searches for ultra-high energy gamma rays and neutrinos.

    ↳ astro-ph.HEhep-phPoS(2025)·0 citations
14. 14*

    Dilaton Physics from Asymptotic Freedom

    Charlie Cresswell-Hogg🇬🇧 · Daniel F. Litim🇬🇧 · Roman Zwicky🇬🇧

    The dilaton is investigated from first principles in an asymptotically free Gross-Neveu-Yukawa theory in three dimensions. In the limit of many fermion flavours, the theory features a finite line of strongly interacting fixed points with continuous quantum phase transitions and a massless Goldstone boson, the dilaton, following spontaneous scale symmetry breaking at its endpoint. Interestingly, we find that the emergence of a vacuum expectation value and a dilaton can be understood as a double-scaling limit. Exploiting the scalar two-point function, we identify the dilaton in the spectrum, compute its decay constant, and obtain universal expressions for the induced dilaton mass in terms of small perturbations. Consistency of findings with soft dilaton theorems is equally established. Implications for spontaneously broken conformal theories are indicated.

    ↳ hep-thhep-lathep-ph10 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.