Fri·Nov 3, 2023Friday·November 3, 2023

1. 01*

   Analyzing the semileptonic and nonleptonic $B_c\to J/\psi ,{\eta }_c$ decays

   Aritra Biswas🇪🇸 · Soumitra Nandi🇮🇳 · Shantanu Sahoo🇮🇳

   This study focuses on the decay of the $B_c$ meson to S-wave charmonia. Starting with lattice inputs on $B_c\to J/\psi$ form factors, we have obtained the $B_c\to {\eta }_c$ form factors using heavy quark spin symmetry (HQSS) relations between the associated form factors after parametrizing and extracting the possible symmetry breaking corrections. Using the $q^2$ shapes of these form factors, we have computed the branching fractions $\mathcal{B}(B_c^{-}\to {\eta }_c{\ell }^{-}\bar{\nu })$ (with $\ell =\tau ,\mu (e)$) and the decay rate distributions and have predicted the Standard model estimate for the observable $R({\eta }_c)=\Gamma (B_c^{-}\to {\eta }_c{\tau }^{-}\bar{\nu })/\Gamma (B_c^{-}\to {\eta }_c{\mu }^{-}\bar{\nu })=0.310\pm 0.042$. In addition, we have estimated the radial wave functions ${\psi }_{B_c}^R(0)$, ${\psi }_{J/\psi }^R(0)$ and ${\psi }_{{\eta }_c}^R(0)$ at small quark-antiquark distances from the available information on the form factors from lattice, the lattice inputs on the decay constants $f_{J/\psi }$, $f_{{\eta }_c}$, $f_{B_c}$ and experimental data on radiative and rare decays of the $J/\psi$ and ${\eta }_c$ mesons. To do so, we choose the theory framework of non-relativistic QCD (NRQCD) effective theory. Using our results, we have predicted the branching fractions of a few non-leptonic decays of $B_c\to J/\psi$ or ${\eta }_c$ and other light mesons. We have also updated the numerical estimates of the cross sections $\sigma (e^{+}{e}^{-}\to J/\psi {\eta }_c,{\eta }_c\gamma )$ and predicted the branching fractions of $Z$ boson decays to either $J/\psi$ or ${\eta }_c$ final states or both.

   hep-phhep-exhep-latJHEP(2025)·8 citations
2. 02*

   Quantum Pathways for Charged Track Finding in High-Energy Collisions

   Christopher Brown🇬🇧 · Michael Spannowsky🇬🇧 · Alexander Tapper🇬🇧 · Simon Williams🇬🇧 · Ioannis Xiotidis🇬🇧

   In high-energy particle collisions, charged track finding is a complex yet crucial endeavour. We propose a quantum algorithm, specifically quantum template matching, to enhance the accuracy and efficiency of track finding. Abstracting the Quantum Amplitude Amplification routine by introducing a data register, and utilising a novel oracle construction, allows data to be parsed to the circuit and matched with a hit-pattern template, without prior knowledge of the input data. Furthermore, we address the challenges posed by missing hit data, demonstrating the ability of the quantum template matching algorithm to successfully identify charged-particle tracks from hit patterns with missing hits. Our findings therefore propose quantum methodologies tailored for real-world applications and underline the potential of quantum computing in collider physics.

   hep-phhep-exquant-phFront.Artif.Intell.(2024)·9 citations
3. 03*

   Scattering Amplitudes of Massive Spin-2 Kaluza-Klein States with Matter

   R. Sekhar Chivukula🇺🇸 · Joshua A. Gill🇦🇺 · Kirtimaan A. Mohan🇺🇸 · Dipan Sengupta🇦🇺 · Elizabeth H. Simmons🇺🇸 · Xing Wang🇺🇸

   We perform a comprehensive analysis of the scattering of matter and gravitational Kaluza-Klein (KK) modes in five-dimensional gravity theories. We consider matter localized on a brane as well as in the bulk of the extra dimension for scalars, fermions and vectors respectively, and consider an arbitrary warped background. While naive power-counting suggests that there are amplitudes which grow as fast as $\mathcal{O}(s^3)$ [where $s$ is the center-of-mass scattering energy-squared], we demonstrate that cancellations between the various contributions result in a total amplitude which grows no faster than $\mathcal{O}(s)$. Extending previous work on the self-interactions of the gravitational KK modes, we show that these cancellations occur due to sum-rule relations between the couplings and the masses of the modes that can be proven from the properties of the mode equations describing the gravity and matter wavefunctions. We demonstrate that these properties are tied to the underlying diffeomorphism invariance of the five-dimensional theory. We discuss how our results generalize when the size of the extra dimension is stabilized via the Goldberger-Wise mechanism. Our conclusions are of particular relevance for freeze-out and freeze-in relic abundance calculations for dark matter models including a spin-2 portal arising from an underlying five-dimensional theory.

   hep-phhep-thPRD(2024)·14 citations
4. 04*

   New tests of short-distance dynamics in $b\to s\bar{\ell }\ell$ decays

   Arianna Tinari🇨🇭

   The rare $B\to K^{(\ast )}\bar{\ell }\ell$ decays exhibit a long-standing tension with Standard Model (SM) predictions, which can be attributed to a lepton-universal short-distance $b\to s\bar{\ell }\ell$ interaction. We present two novel methods to disentangle this effect from long-distance dynamics: one based on the determination of the inclusive $b\to s\bar{\ell }\ell$ rate at high dilepton invariant mass ($q^2\ge 15{\mathrm{GeV}}^2$), the other based on the analysis of the $q^2$ spectrum of the exclusive modes $B\to K^{(\ast )}\bar{\ell }\ell$ (in the entire $q^2$ range). Using the first method, we show that the SM prediction for the inclusive $b\to s\bar{\ell }\ell$ rate at high dilepton invariant mass is in good agreement with the result obtained summing the SM predictions for one- and two-body modes ($K$, $K^{\ast }$, $K\pi$). This observation allows us to perform a direct comparison of the inclusive $b\to s\bar{\ell }\ell$ rate with data. This comparison shows a significant deficit ($\sim 2\sigma$) in the data, fully compatible with the deficit observed at low-$q^2$ on the exclusive modes. This provides independent evidence of an anomalous $b\to s\bar{\ell }\ell$ short-distance interaction, free from uncertainties on the hadronic form factors. To test the short-distance nature of this effect we use a second method, where we analyze the exclusive $B\to K^{(\ast )}\bar{\ell }\ell$ data in the entire $q^2$ region. Here, after using a dispersive parametrization of the charmonia resonances, we extract the non-SM contribution to the universal Wilson coefficient $C_9$ for every bin in $q^2$ and for every polarization. The $q^2$- and polarization-independence of the result, and its compatibility with the inclusive determination, provide a consistency check of the short-distance nature of this effect.

   hep-phPoS(2024)·0 citations
5. 05*

   A model independent description of $B\to D\pi \ell \nu$ decays

   Erik J. Gustafson🇺🇸 · Florian Herren🇺🇸 · Ruth S. Van de Water🇺🇸 · Raynette van Tonder🇨🇦 · Michael L. Wagman🇺🇸

   We introduce a new parameterization of $B\to D\pi \ell \nu$ form factors using a partial-wave expansion and derive bounds on the series coefficients using analyticity and unitarity. This is the first generalization of the model-independent formalism developed by Boyd, Grinstein, and Lebed for $B\to D\ell \nu$ to semileptonic decays with multi-hadron final states, and enables data-driven form factor determinations with robust, systematically-improvable uncertainties. Using this formalism, we extract the form-factor parameters for $B\to D_2^{\ast }(\to D\pi )\ell \nu$ decays in a model-independent way from fits of data from the Belle Experiment, and, for the first time, study the two-pole structure in the $D\pi$ S-wave in semileptonic decays employing lineshapes from unitarized chiral perturbation theory.

   hep-phhep-exhep-latPRD(2024)·22 citations
6. 06*

   Everlasting interaction: polarization summation without a Landau pole

   Stefan Evans🇺🇸 · Johann Rafelski🇺🇸

   We propose an external field approach to evaluating effective action allowing the interaction to act everywhere at all times (everlasting). Requiring that the asymptotic gauge fields are always-interacting, we implement displacement fields encoding polarization corrections into the derivation of effective action. The result is a novel polarization summation for one-cut reducible loop diagrams, which can be applied to two cases: transient quasi-constant electromagnetic fields, and everlasting interactions. In the first case, a perturbative expansion of our result recovers the Schwinger-Dyson reducible diagram series with a Landau pole. The everlasting summation evaluated in nonperturbative fashion removes the Landau pole, providing a new avenue for modeling strongly interacting theories.

   hep-phPRD(2024)·2 citations
7. 07*

   Hidden-charm pentaquarks with strangeness in a chiral quark model

   Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸

   The LHCb collaboration has recently announced the discovery of two hidden-charm pentaquark states with also strange quark content, $P_{cs}(4338)$ and $P_{cs}(4459)$; its analysis points towards having both hadrons isospin equal to zero and spin-parity quantum numbers ${\frac{1}{2}}^{-}$ and ${\frac{3}{2}}^{-}$, respectively. We perform herein a systematical investigation of the $qqsc\bar{c}$ $(q=u,d)$ system by means of a chiral quark model, along with a highly accurate computational method, the Gaussian expansion approach combined with the complex-scaling technique. Baryon-meson configurations in both singlet- and hidden-color channels are considered. The $P_{cs}(4338)$ and $P_{cs}(4459)$ signals can be well identified as molecular bound states with dominant components $\Lambda J/\psi$ $(60\%)$ and ${\Xi }_{c}D$ $(23\%)$ for the lowest-energy case and ${\Xi }_c{D}^{\ast }$ $(72\%)$ for the highest-energy one. Besides, it seems that some narrow resonances can be also found in each allowed $I(J^P)$-channel in the energy region of $4.6-5.5$ GeV, except for the $1({\frac{1}{2}}^{-})$ where a shallow bound state with dominant ${\Xi }_c^{\ast }{D}^{\ast }$ structure is obtained at $4673$ MeV with binding energy $E_B=-3$ MeV. These exotic states are expected to be confirmed in future high energy experiments.

   hep-phhep-exhep-latnucl-ex+1Symmetry(2024)·14 citations
8. 08*

   Wash-in leptogenesis after the evaporation of primordial black holes

   Kai Schmitz🇩🇪 · Xun-Jie Xu🇨🇳

   Wash-in leptogenesis is a powerful mechanism to generate the baryon asymmetry of the Universe that treats right-handed-neutrino interactions on the same footing as electroweak sphaleron processes: as mere spectator processes acting on the background of chemical potentials in the Standard Model plasma. Successful wash-in leptogenesis requires this chemical background to be CP-violating, which can be achieved by violating any of the more than ten global charges that are conserved in the Standard Model at very high temperatures. In this paper, we demonstrate that the primordial charge asymmetries required for wash-in leptogenesis can be readily produced by evaporating primordial black holes (PBHs). Our argument is based on the fact that the Hawking radiation emitted by PBHs contains more or less any state in the particle spectrum. Therefore, if heavy states with CP-violating decays are present in the ultraviolet, PBH evaporation will unavoidably lead to the production of these states. We illustrate this scenario by means of a simple toy model where PBH evaporation leads to the production of heavy particles that we call asymmetrons and whose decay results in a primordial charge asymmetry for right-handed electrons, which in turn sets the initial conditions for wash-in leptogenesis. We focus on the parameter region where the decay of the initial thermal asymmetron abundance occurs long before PBH evaporation and only results in a negligible primordial charge asymmetry. PBH evaporation at later times then serves as a mechanism to resurrect the asymmetron abundance and ensure the successful generation of the baryon asymmetry after all. We conclude that PBHs can act as asymmetry-producing machines that grant access to whatever CP-violating physics may be present in the ultraviolet, rekindling it at lower energies where it can be reprocessed into a baryon asymmetry by right-handed neutrinos.

   hep-phastro-ph.COhep-thPLB(2024)·29 citations
9. 09*

   Phase diagram of QCD matter with magnetic field: domain-wall Skyrmion chain in chiral soliton lattice

   Minoru Eto🇯🇵 · Kentaro Nishimura🇯🇵 · Muneto Nitta🇯🇵

   QCD matter in strong magnetic field exhibits a rich phase structure. In the presence of an external magnetic field, the chiral Lagrangian for two flavors is accompanied by the Wess-Zumino-Witten (WZW) term containing an anomalous coupling of the neutral pion ${\pi }_0$ to the magnetic field via the chiral anomaly. Due to this term, the ground state is inhomogeneous in the form of either chiral soliton lattice (CSL), an array of solitons in the direction of magnetic field, or domain-wall Skyrmion (DWSk) phase in which Skyrmions supported by ${\pi }_3[\mathrm{SU}(2)]\simeq \mathbb{Z}$ appear inside the solitons as topological lumps supported by ${\pi }_2(S^2)\simeq \mathbb{Z}$ in the effective worldvolume theory of the soliton. In this paper, we determine the phase boundary between the CSL and DWSk phases beyond the single-soliton approximation, within the leading order of chiral perturbation theory. To this end, we explore a domain-wall Skyrmion chain in multiple soliton configurations. First, we construct the effective theory of the CSL by the moduli approximation, and obtain the $\mathbb{C}{P}^1$ model or O(3) model, gauged by a background electromagnetic gauge field, with two kinds of topological terms coming from the WZW term: one is the topological lump charge in 2+1 dimensional worldvolume and the other is a topological term counting the soliton number. Topological lumps in the 2+1 dimensional worldvolume theory are superconducting rings and their sizes are constrained by the flux quantization condition. The negative energy condition of the lumps yields the phase boundary between the CSL and DWSk phases. We find that a large region inside the CSL is occupied by the DWSk phase, and that the CSL remains metastable in the DWSk phase in the vicinity of the phase boundary.

   hep-phhep-thJHEP(2023)·33 citations
10. 10*

    Precise predictions for the trilinear Higgs self-coupling in the Standard Model and beyond

    Henning Bahl🇺🇸 · Johannes Braathen🇩🇪 · Martin Gabelmann🇩🇪 · Georg Weiglein🇩🇪

    Deviations in the trilinear self-coupling of the Higgs boson at 125 GeV from the Standard Model (SM) prediction are a sensitive test of physics Beyond the SM (BSM). The LHC experiments searching for the simultaneous production of two Higgs bosons start to become sensitive to such deviations. Therefore, precise predictions for the trilinear Higgs self-coupling in different BSM models are required in order to be able to test them against current and future bounds. We present the new framework $\text{anyH3}$, which is a $\text{Python}$ library that can be utilized to obtain predictions for trilinear scalar couplings up to the one-loop level in any renormalisable theory. The program makes use of the $\text{UFO}$ format as input and is able to automatically apply a wide variety of renormalisation schemes involving minimal and non-minimal subtraction conditions. External-leg corrections are also computed automatically, and finite external momenta can be optionally taken into account. The $\text{Python}$ library comes with convenient command-line as well as $\text{Mathematica}$ user interfaces. We perform cross-checks using consistency conditions such as UV-finiteness and decoupling, and also by comparing against results know in the literature. As example applications, we obtain results for the trilinear self-coupling of the SM-like Higgs boson in various concrete BSM models, study the effect of external momenta as well as of different renormalisation schemes.

    hep-phPoS(2024)·1 citation
11. 11*

    libepa -- a C++/Python library for calculations of cross sections of ultraperipheral collisions

    E. V. Zhemchugov🇷🇺 · S. I. Godunov🇷🇺 · E. K. Karkaryan🇷🇺 · V. A. Novikov🇷🇺 · A. N. Rozanov🇫🇷 · M. I. Vysotsky🇷🇺

    The library provides a set of C++/Python functions for computing cross sections of ultraperipheral collisions of high energy particles under the equivalent photons approximation. Cross sections are represented through multiple integrals over the phase space. The integrals are calculated through recurrent application of algorithms for one dimensional integration. The paper contains an introduction to the theory of ultraperipheral collisions, discusses the library approach and provides a few examples of calculations.

    hep-phComput.Phys.Commun.(2024)·5 citations
12. 12*

    Transverse Momentum Distributions from Lattice QCD without Wilson Lines

    Yong Zhao🇺🇸

    The transverse-momentum-dependent distributions (TMDs), which are defined by gauge-invariant 3D parton correlators with staple-shaped lightlike Wilson lines, can be calculated from quark and gluon correlators fixed in the Coulomb gauge on a Euclidean lattice. These quantities can be expressed gauge-invariantly as the correlators of Coulomb-gauge-dressed fields, which reduce to the standard TMD correlators under principal-value prescription in the infinite boost limit. In the framework of Large-Momentum Effective Theory, a quasi-TMD defined from such correlators in a large-momentum hadron state can be matched to the TMD via a factorization formula, whose exact form is derived using Soft Collinear Effective Theory and verified at one-loop order. Compared to the currently used gauge-invariant correlators, this new method can substantially improve statistical precision and simplify renormalization for the time-reversal-even TMDs, which will greatly enhance the predicative power of lattice QCD in the non-perturbative region.

    hep-phhep-exhep-lathep-th+1PRL(2024)·38 citations
13. 13*

    Tetraquarks made of sufficiently unequal-mass heavy quarks are bound in QCD

    Benoît Assi🇺🇸 · Michael L. Wagman🇺🇸

    Tetraquarks, bound states composed of two quarks and two antiquarks, have been the subject of intense study but are challenging to understand from first principles. We apply variational and Green's function Monte Carlo methods to compute tetraquark ground-state energies in potential nonrelativistic QCD using a wide range of color and spatial wavefunctions. We find no evidence for bound tetraquarks composed of equal-mass quarks and antiquarks. Conversely, we find clear evidence for the existence of bound tetraquarks for sufficiently unequal quark/antiquark mass ratios at all overall mass scales where our effective theory results are applicable. We predict the critical mass ratios for bound state formation and study tetraquark bound states' spatial and color structure at leading order and next-to-leading order in potential nonrelativistic QCD.

    hep-phhep-latPRD(2024)·10 citations
14. 14*

    Gravity-Matter Sum Rules in models with a single extra-dimension

    A. de Giorgi🇪🇸 · S. Vogl🇩🇪

    We prove a set of sum rules needed for KK-graviton pair production from matter in orbifolded extra-dimensional models. The sum rules can be found in full generality by considering the properties of solutions to the Sturm-Liouville problem, which describes the wave functions and the masses of the KK-gravitons in four dimensions. They ensure cancellations in the amplitudes of the processes mentioned above which considerably reduce their growth with $s$ in the high-energy limit. This protects extra-dimensional theories from the low-scale unitarity problems that plague other theories with massive spin-2 particles. We argue that such relations are valid for a broader category of models thus generalizing our previous results that were limited to the large $\mu$ limit of the Randall-Sundrum model.

    hep-phhep-thJHEP(2024)·9 citations
15. 15*

    Measurements of charged-particle multiplicity dependence of higher-order net-proton cumulants in $p$+$p$ collisions at $\sqrt{s}=$ 200 GeV from STAR at RHIC

    STAR Collaboration: M. I. Abdulhamid🇪🇬 · B. E. Aboona🇺🇸 · J. Adam🇨🇿 · L. Adamczyk🇵🇱 · J. R. Adams🇺🇸 · I. Aggarwal🇮🇳 · M. M. Aggarwal🇮🇳 · Z. Ahammed🇮🇳 · E. C. Aschenauer🇺🇸 · S. Aslam🇮🇳 · J. Atchison🇺🇸 · V. Bairathi🇨🇱 and 350 other authors

    We report on the charged-particle multiplicity dependence of net-proton cumulant ratios up to sixth order from $\sqrt{s}=200$ GeV $p$+$p$ collisions at the Relativistic Heavy Ion Collider (RHIC). The measured ratios $C_4/C_2$, $C_5/C_1$, and $C_6/C_2$ decrease with increased charged-particle multiplicity and rapidity acceptance. Neither the Skellam baselines nor PYTHIA8 calculations account for the observed multiplicity dependence. In addition, the ratios $C_5/C_1$ and $C_6/C_2$ approach negative values in the highest-multiplicity events, which implies that thermalized QCD matter may be formed in $p$+$p$ collisions.

    ↳ nucl-exhep-exhep-phnucl-thPLB(2024)·9 citations
16. 16*

    Polarization effects in elastic deuteron-electron scattering

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

    The differential cross section and polarization observables for the elastic reaction induced by deuteron scattering off electrons at rest are calculated in the one-photon-exchange (Born) approximation. Specific attention is given to the kinematical conditions, that is, to the specific range of incident energy and transferred momentum. The specific interest of this reaction is to access very small transferred momenta. Numerical estimates are given for polarization observables that describe the of single- and double-spin effects, provided that the polarization components (both, vector and tensor) of each particle in the reaction are determined in the rest frame of the electron target.

    ↳ nucl-thhep-phPRC(2024)·1 citation
17. 17*

    Third-order relativistic fluid dynamics at finite density in a general hydrodynamic frame

    Saulo M. Diles🇧🇷 · Alex S. Miranda🇧🇷 · Luis A. H. Mamani🇧🇷 · Alex M. Echemendia🇧🇷 · Vilson T. Zanchin🇧🇷

    The motion of water is governed by the Navier-Stokes equations, which are complemented by the continuity equation to ensure local mass conservation. In this work, we construct the relativistic generalization of these equations through a gradient expansion for a fluid with conserved charge in a curved $d$-dimensional spacetime. We adopt a general hydrodynamic frame approach and introduce the Irreducible-Structure (IS) algorithm, which is based on derivatives of both the expansion scalar and the shear and vorticity tensors. By this method, we systematically generate all permissible gradients up to a specified order and derive the most comprehensive constitutive relations for a charged fluid, accurate to third-order gradients. These constitutive relations are formulated to apply to ordinary, non-conformal, and conformally invariant charged fluids. Furthermore, we examine the hydrodynamic frame dependence of the transport coefficients for a non-conformal charged fluid up to the third order in the gradient expansion. The frame dependence of the scalar, vector, and tensor parts of the constitutive relations is obtained in terms of the field redefinitions of the fundamental hydrodynamic variables. Managing these frame dependencies is challenging due to their non-linear character. However, in the linear regime, these higher-order transformations become tractable, enabling the identification of a set of frame-invariant coefficients. An advantage of employing these coefficients is the possibility of studying the linear equations of motion in any chosen frame and, hence, we apply this approach to the Landau frame. Subsequently, these linear equations are solved in momentum space, yielding dispersion relations for shear, sound, and diffusive modes for a non-conformal charged fluid, expressed in terms of the frame-invariant transport coefficients.

    ↳ hep-thgr-qchep-phnucl-th+1EPJC(2024)·6 citations
18. 18*

    Rotating Bose-Einstein Condensate Stars at finite temperature

    P. S. Aswathi🇮🇳 · P. S. Keerthi🇮🇳 · O. P. Jyothilakshmi🇮🇳 · Lakshmi J. Naik🇮🇳 · V. Sreekanth🇮🇳

    We study the effect of temperature on the global properties of static and slowly rotating self-gravitating Bose-Einstein condensate (BEC) stars within general relativity. We employ a recently developed temperature dependent BEC equation of state (EoS) to describe the stellar matter by assuming that the condensate can be described by a non-relativistic EoS. Stellar profiles are obtained using general relativistic Hartle-Thorne slow rotation approximation equations. We find that with increasing temperatures mass-radius values are found to be decreasing for the static and rotating cases; though presence of temperature supports high mass values at lower central densities. Countering effects of rotation and temperature on the BEC stellar structure have been analysed and quantified. We report that inclusion of temperature has significant effect on the rotating stellar profiles but negligible effect on the maximum mass, as in the case of static system. We have also studied the effect of EoS parameters -- boson mass and strength of the self-interaction -- on global properties of static and rotating BEC stars, in presence of temperature.

    ↳ gr-qcastro-ph.HEhep-phnucl-thPRD(2023)·6 citations
19. 19*

    Binary Black Holes and Quantum Off-Shell Recursion

    Kyoungho Cho🇰🇷 · Kwangeon Kim🇰🇷 · Kanghoon Lee🇰🇷

    The quantum off-shell recursion provides an efficient and universal computational tool for loop-level scattering amplitudes. In this work, we present a new comprehensive computational framework based on the quantum off-shell recursion for binary black hole systems. Using the quantum perturbiner method, we derive the recursions and solve them explicitly up to two-loop order. We develop a power-counting prescription that enables the straightforward separation of classical diagrams. We also devise a classification scheme that optimizes the integration by parts (IBP) reduction process, which makes higher-loop calculations more tractable. By employing the soft expansion technique, we remove irrelevant terms from the loop integrands and express them in terms of master integrals. We classify the one-loop and the two-loop classical diagrams, and their loop integrands are represented by linear combinations of the master integrals. Finally, we explicitly calculate the classical scalar 2 to 2 amplitudes in the potential region up to the 3PM order and reproduce the known results.

    ↳ hep-thgr-qchep-phJHEP(2024)·17 citations
20. 20*

    Raoul Gatto and Bruno Touschek's joint legacy in the rise of electron-positron physics

    Luisa Bonolis (MPIWG, Berlin)🇩🇪 · Franco Buccella (INFN Rome1)🇮🇹 · Giulia Pancheri (INFN-LNF and CREF)🇮🇹

    Raoul Gatto and Bruno Touschek's collaboration in the establishment of electron positron colliders as a fundamental discovery tool in particle physics will be illustrated. In particular, we will tell the little-known story of how Gatto and Touschek's pioneering vision combined to provide the theoretical foundations for AdA, the first matter-antimatter collider, and how their friendship with Wolfgang Pauli and Gerhard Lüders was crucial to their understanding of the CPT theorem, the basis for AdA's success. We will see how these two exceptional scientists shaped physics between Rome and Frascati, from the proposal to build AdA and, soon after in 1961, the larger machine ADONE, to the discovery of the $J/\Psi$ particle in 1974. We will also highlight Gatto and Touschek's contribution in mentoring an extraordinary cohort of students and collaborators whose work contributed to the renaissance of Italian theoretical physics after the Second World War and to the establishment of the Standard Model of particle physics.

    ↳ physics.hist-phhep-phEur.Phys.J.H(2024)·4 citations
21. 21*

    Lattice QCD Constraints on the Fourth Mellin Moment of the Pion Light Cone Distribution Amplitude using the HOPE method

    William Detmold🇺🇸 · Anthony V. Grebe🇺🇸 · Issaku Kanamori🇯🇵 · C.-J. David Lin🇹🇼 · Robert J. Perry🇪🇸 · Yong Zhao🇺🇸

    The light-cone distribution amplitude (LCDA) of the pion contains information about the parton momentum carried by the quarks and is an important theoretical input for various predictions of exclusive processes at high energy, including the pion electromagnetic form factor. Progress towards constraining the fourth Mellin moment of the LCDA using the heavy-quark operator product expansion (HOPE) method is presented.

    ↳ hep-lathep-phnucl-th2 citations
22. 22*

    Cosmological foundations revisited with Pantheon+

    Zachary G. Lane🇳🇿 · Antonia Seifert🇳🇿 · Ryan Ridden-Harper🇳🇿 · David L. Wiltshire🇳🇿

    We reanalyse the Pantheon+ supernova catalogue to compare a cosmology with non-FLRW evolution, the timescape cosmology, with the standard $\Lambda$CDM cosmology. To this end, we analyse the Pantheon+ for a geometric comparison between the two models. We construct a covariance matrix to be as independent of cosmology as possible, including independence from the FLRW geometry and peculiar velocity with respect to FLRW average evolution. This framework goes far beyond most other definitions of model independence. We introduce new statistics to refine Type Ia supernova (SNe Ia) light-curve analysis. In addition to conventional galaxy correlation functions used to define the scale of statistical homogeneity we introduce empirical statistics which enables refined analysis of the distribution biases of SNe Ia light-curve parameters $\beta c$ and $\alpha x_1$. For lower redshifts, the Bayesian analysis highlights important features attributable to the increased number of low-redshift supernovae, the artefacts of model-dependent light-curve fitting and the cosmic structure through which we observe supernovae. This indicates the need for cosmology-independent data reduction to conduct a stronger investigation of the emergence of statistical homogeneity and to compare alternative cosmologies in light of recent challenges to the standard model. Dark energy is generally invoked as a place-holder for new physics. For the first time, we find evidence that the timescape cosmology may provide a better overall fit than $\Lambda$CDM and that its phenomenology may help disentangle other astrophysical puzzles. Our from-first-principles reanalysis of Pantheon+ supports future deeper studies between the interplay of matter and nonlinear spacetime geometry in a data-driven setting.

    ↳ astro-ph.COastro-ph.HEgr-qchep-ph+1MNRAS(2025)·25 citations
23. 23*

    Induced Circular Polarization on Photons Due to Interaction with Axion-Like Particles in Rotating Magnetic Field of Neutron Stars

    Mohammad Sharifian🇮🇷 · Moslem Zarei🇮🇷 · Sabino Matarrese🇮🇹 · Roberto Turolla🇮🇹

    We investigate how the photon polarization is affected by the interaction with axion-like particles (ALPs) in the rotating magnetic field of a neutron star (NS). Using quantum Boltzmann equations the study demonstrates that the periodic magnetic field of millisecond NSs enhances the interaction of photons with ALPs and creates a circular polarization on them. A binary system including an NS and a companion star could serve as a probe. When the NS is in front of the companion star with respect to the earth observer, there is a circular polarization on the previously linearly polarized photons as a result of the interaction with ALPs there. After a half-binary period, the companion star passes in front of the NS, and the circular polarization of photons disappears and changes to linear. The excluded parameter space for a millisecond NS with 300~Hz rotating frequency, highlights the coupling constant of $1.7\times 10^{-11}{\text{GeV}}^{-1}\le g_{a\gamma \gamma }\le 1.6\times 10^{-3}{\text{GeV}}^{-1}$ for the ALP masses in the range of $7\times 10^{-12}\text{eV}\le m_a\le 1.5\times 10^3\text{eV}$.

    ↳ astro-ph.HEgr-qchep-phJCAP(2024)·1 citation
24. 24*

    The Influence of Fractional Derivatives on Thermodynamic Properties by Studying the CPSEHP Interaction

    M. Abu-Shady🇪🇬 · Sh. Y. Ezz-Alarab

    The parametric Nikiforov-Uvarov (N-U) method is employed in conjunction with a generalized fractional derivative (GFD) to investigate the energy eigenvalues and the total normalized wave function associated with the Coulomb plus screened exponential hyperbolic potential (CPSEHP) in terms of Jacobi polynomials. This potential exhibits maximum effectiveness at lower values of the screening parameter. To explore the thermal and superstatistical characteristics, the derived energy eigenvalues are directly incorporated into the partition function (Z) and subsequently used to determine other thermodynamic quantities, including vibrational mean energy (U), specific heat capacity (C), entropy (S), and free energy (F). Comparisons with previous studies are conducted. The classical case is recovered from the fractional case by setting alpha = beta = 1, consistent with prior work. Our results demonstrate that the fractional parameter plays a crucial role in governing the thermal and superstatistical properties within the framework of this model.

    ↳ cond-mat.stat-mechhep-phEast Eur.J.Phys.(2025)·2 citations

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