Thu·Jul 13, 2023Thursday·July 13, 2023

1. 01*

   Exploring high-purity multi-parton scattering at hadron colliders

   Jeppe R. Andersen🇬🇧 · Pier Francesco Monni🇨🇭 · Luca Rottoli🇨🇭 · Gavin P. Salam🇬🇧 · Alba Soto-Ontoso🇨🇭

   Multi-parton interactions are a fascinating phenomenon that occur in almost every high-energy hadron--hadron collision, yet are remarkably difficult to study quantitatively. In this letter we present a strategy to optimally disentangle multi-parton interactions from the primary scattering in a collision. That strategy enables probes of multi-parton interactions that are significantly beyond the state of the art, including their characteristic momentum scale, the interconnection between primary and secondary scatters, and the pattern of three and potentially even more simultaneous hard scatterings. This opens a path to powerful new constraints on multi-parton interactions for LHC phenomenology and to the investigation of their rich field-theoretical structure.

   hep-phhep-exPRL(2024)·9 citations
2. 02*

   Electromagnetic bremsstrahlung and energy loss in chiral medium

   Jeremy Hansen🇺🇸 · Kirill Tuchin🇺🇸

   We study electromagnetic radiation by a fast particle carrying electric charge in chiral medium. The medium is homogeneous and isotropic and supports the chiral magnetic current which renders the fermion and photon states unstable. The instability manifests as the chirality-dependent resonances in the bremsstrahlung cross section, which enhance the energy loss in the chiral medium. We compute the corresponding cross sections in the single scattering approximation and derive the energy loss in the high energy approximation.

   hep-phPRD(2023)·8 citations
3. 03*

   Chemical freeze-out parametrization with mean field repulsive hadron resonance gas model

   Sunny Kumar Singh🇮🇳 · Nachiketa Sarkar🇮🇳 · Deeptak Biswas🇮🇳

   We have examined the chemical freeze-out surface of the heavy-ion collision experiments within an interacting hadron resonance gas model. By considering repulsive interaction among hadrons in the mean-field level, we have suitably parameterized the freeze-out surface by fitting the yield data of mid-rapidity for the most central collision, for the collision energy available in AGS, RHIC (BES), and LHC programs. To suitably account for the repulsive interaction among mesons and (anti-) baryons, we have introduced phenomenological parameters $K_M$ and $K_B$ in the freeze-out parametrization. Although a finite value of these two parameters seem to be necessary to have an improved normalized \emph{chi-square}, the effect on the rest of the parameters like temperature and relevant chemical potentials seem to be within the standard variance.

   hep-phnucl-th0 citations
4. 04*

   Towards an integrated determination of proton, deuteron and nuclear PDFs

   Tanjona Rabemananjara🇳🇱

   We present progress towards a unified framework enabling the simultaneous determination of the parton distribution functions (PDFs) of the proton, deuteron, and nuclei up to lead ${(}^{208}\mathrm{Pb})$. Our approach is based on the integration of the fitting framework underlying the nNNPDF3.0 determination of nuclear PDFs into that adopted for the NNPDF4.0 global analysis of proton PDFs. Our work paves the way toward a full integrated global analysis of non-perturbative QCD -- a key ingredient for the exploitation of the scientific potential of present and future nuclear and particle physics facilities such as the Electron-Ion Collider (EIC).

   hep-ph0 citations
5. 05*

   QCD effective charges from low-energy neutrino structure functions

   Tanjona Rabemananjara🇳🇱

   We present a new perspective on the study of the behavior of the strong coupling ${\alpha }_s(Q^2)$ -- the fundamental coupling underlying the interactions between quarks and gluons as described by the Quantum Chromodynamics (QCD) -- in the low-energy infrared (IR) regime. We rely on the NNSF$\nu$ determination of neutrino-nucleus structure functions valid for all values of $Q^2$ from the photoproduction to the high-energy region to define an effective charge following the the Gross-Llewellyn Smith (GLS) sum rule. As a validation, our predictions for the low-energy QCD effective charge are compared to experimental measurements provided by JLab.

   hep-ph0 citations
6. 06*

   Reheating and Leptogenesis after Vector inflation

   Simon Cléry (IJCLab, Orsay)🇫🇷 · Pascal Anastasopoulos (Vienna, OAW)🇦🇹 · Yann Mambrini (IJCLab, Orsay)🇫🇷

   We study the reheating and non-thermal leptogenesis in the case of a vector inflaton. We concentrate on particle production during the phase of oscillating background, especially gravitational production induced by the presence of non-minimal coupling imposed by an isotropic and homogeneous Universe. Including processes involving the exchange of graviton, we then extend our study to decay into fermions via direct or anomalous couplings. The necessity of non-minimal gravitational coupling and the gauge nature of couplings to fermions implies a much richer phenomenology than for a scalar inflaton.

   hep-phastro-ph.COJCAP(2024)·5 citations
7. 07*

   Synergies of Drell-Yan, beauty, top, and Z observables in MFV-SMEFT

   Cornelius Grunwald🇩🇪 · Gudrun Hiller🇩🇪 · Kevin Kröninger🇩🇪 · Lara Nollen🇩🇪

   The Standard Model Effective Field Theory (SMEFT) is a powerful tool to search for new physics in a model-independent way. We explore the synergies arising from different types of observables in a combined, global SMEFT fit. Specifically, we investigate the combination of top-quark measurements, $b\to s$ flavor changing neutral current transitions, $Z\to b\bar{b}$ and $Z\to c\bar{c}$, as well as Drell-Yan data from the LHC. We also examine the impact of Minimal Flavor Violation (MFV) as a flavor pattern in the global fit. We find that the combination of high-p${}_T$ with flavor physics observables provides powerful synergies that significantly improve the fit and enable more precise tests of various SMEFT operators. By incorporating different observables, we are able to remove flat directions in the parameter space and infer on the flavor structure based on the MFV parameterization. In particular, we find that MFV significantly strengthens the constraints in comparison to a flavor-specific approach. Furthermore, our analysis yields a prediction for the dineutrino branching ratios $\mathcal{B}(B\to K^{(\ast )}\nu \bar{\nu })$ within MFV, which can be tested experimentally at Belle II.

   hep-phhep-exPoS·0 citations
8. 08*

   A comparative study of different approaches for heavy quark energy loss, based on the latest experimental data

   Marjan Rahimi Nezhad🇮🇷 · Fatemeh Taghavi Shahri🇮🇷 · Sharareh Mehrabi Pari🇮🇷 · Kurosh Javidan🇮🇷

   This paper presents a comparative analysis of three distinct methods used to calculate the collisional energy loss of heavy quarks in Quark-Gluon Plasma. The study focuses on the calculation of the nuclear suppression factor of charm quarks in Pb-Pb collisions at $\sqrt{S_{NN}}=5.02$ TeV. All three models are examined using the same numerical evolution based on the well-known Fokker-Planck equation by considering critical phenomena like a non-equilibrium state at the onset of heavy ion collision. The outcomes of each approach are compared with the latest data from ALICE and ATLAS experiments spanning from 2018 to 2022. This study aims to compare the degree of agreement between each approach and recently obtained experimental data, in the intermediate and high $P_T$ regions.

   hep-phnucl-thEur.Phys.J.Plus(2024)·3 citations
9. 09*

   Decoherence effects on lepton number violation from heavy neutrino-antineutrino oscillations

   Stefan Antusch🇨🇭 · Jan Hajer🇵🇹 · Johannes Rosskopp🇨🇭

   We study decoherence effects and phase corrections in heavy neutrino-antineutrino oscillations (NNOs), based on quantum field theory with external wave packets. Decoherence damps the oscillation pattern, making it harder to resolve experimentally. Additionally, it enhances lepton number violation (LNV) for processes in symmetry-protected low-scale seesaw models by reducing the destructive interference between mass eigenstates. We discuss a novel time-independent shift in the phase and derive formulae for calculating decoherence effects and the phase shift in the relevant regimes, which are the no dispersion regime and transverse dispersion regime. We find that the phase shift can be neglected in the parameter region under consideration since it is small apart from parameter regions with large damping. In the oscillation formulae, decoherence can be included by an effective damping parameter. We discuss this parameter and present averaged results, which apply to simulations of NNOs in the dilepton-dijet channel at the HL-LHC. We show that including decoherence effects can dramatically change the theoretical prediction for the ratio of LNV over LNC events.

   hep-phJHEP(2023)·22 citations
10. 10*

    In-medium gluon radiation spectrum with all-order resummation of multiple scatterings in longitudinally evolving media

    Carlota Andres🇫🇷 · Liliana Apolinário🇵🇹 · Fabio Dominguez🇪🇸 · Marcos Gonzalez Martinez🇪🇸

    Over the past years, there has been a sustained effort to systematically enhance our understanding of medium-induced emissions occurring in the quark-gluon plasma, driven by the ultimate goal of advancing our comprehension of jet quenching phenomena. To ensure meaningful comparisons between these new calculations and experimental data, it becomes crucial to model the interplay between the radiation process and the evolution of the medium parameters, typically described by a hydrodynamical simulation. This step presents particular challenges when dealing with calculations involving the resummation of multiple scatterings, which have been shown to be necessary for achieving an accurate description of the in-medium emission process. In this paper, we extend our numerical calculations of the fully-resummed gluon spectrum to account for longitudinally expanding media. This new implementation allows us to quantitatively assess the accuracy of previously proposed scaling laws that establish a correspondence between an expanding medium and a ``static equivalent''. Additionally, we show that such scaling laws yield significantly improved results when the static reference case is replaced by an expanding medium with the temperature following a simple power-law decay. Such correspondence will enable the application of numerical calculations of medium-induced energy loss in realistic evolving media for a broader range of phenomenological studies.

    hep-phnucl-thJHEP(2024)·19 citations
11. 11*

    Diffractive Deep Inelastic Scattering in the Dipole Picture at Next-to-Leading Order

    G. Beuf🇵🇱 · H. Hänninen🇫🇮 · T. Lappi🇫🇮 · H. Mäntysaari🇫🇮 · Y. Mulian🇪🇸

    We calculate the contribution from the $q\bar{q}g$ state production to the diffractive cross sections in deep inelastic scattering at high energy. The obtained cross section is finite by itself, and consists a part of the full next-to-leading order result for the diffractive structure functions. Our calculation for the diffractive structure functions is performed using exact kinematics, under the shockwave approximation of the scattering process. Once the calculation is completed, we show that the previously known behaviour at the high-$Q^2$ and large-$M_X^2$ regime can be extracted from our results by taking the appropriate limits. Furthermore, we discuss the steps required to obtain the complete next-to-leading order results for the structure functions in the color glass condensate (CGC) formalism, and the application of these results to phenomenology.

    hep-phnucl-th0 citations
12. 12*

    Factorization of Non-Global LHC Observables and Resummation of Super-Leading Logarithms

    Thomas Becher (Univ. Bern)🇨🇭 · Matthias Neubert (JGU Mainz)🇺🇸 · Ding Yu Shao (Fudan Univ.)🇨🇳 · Michel Stillger (JGU Mainz)🇩🇪

    We present a systematic formalism based on a factorization theorem in soft-collinear effective theory to describe non-global observables at hadron colliders, such as gap-between-jets cross sections. The cross sections are factorized into convolutions of hard functions, capturing the dependence on the partonic center-of-mass energy $\sqrt{\hat{s}}$, and low-energy matrix elements, which are sensitive to the low scale $Q_0\ll \sqrt{\hat{s}}$ characteristic of the veto imposed on energetic emissions into the gap between the jets. The scale evolution of both objects is governed by a renormalization-group equation, which we derive at one-loop order. By solving the evolution equation for the hard functions for arbitrary $2\to M$ jet processes in the leading logarithmic approximation, we accomplish for the first time the all-order resummation of the so-called "super-leading logarithms" discovered in 2006, thereby solving an old problem of quantum field theory. We study the numerical size of the corresponding effects for different partonic scattering processes and explain why they are sizable for $pp\to 2\text{jets}$ processes, but suppressed in $H/Z$ and $H/Z$+jet production. The super-leading logarithms are given by an alternating series, whose individual terms can be much larger than the resummed result, even in very high orders of the loop expansion. Resummation is therefore essential to control these effects. We find that the asymptotic fall-off of the resummed series is much weaker than for standard Sudakov form factors.

    hep-phJHEP(2023)·38 citations
13. 13*

    Fusing photons into nothing, a new search for invisible ALPs and Dark Matter at Belle II

    Francesca Acanfora🇮🇹 · Roberto Franceschini🇮🇹 · Alessio Mastroddi🇮🇹 · Diego Redigolo🇮🇹

    We consider an axion-like particle coupled to the Standard Model photons and decaying invisibly at Belle II. We propose a new search in the $e^{+}{e}^{-}+\text{invisible}$ channel that we compare against the standard $\gamma +\text{invisible}$ channel. We find that the $e^{+}{e}^{-}+\text{invisible}$ channel has the potential to ameliorate the reach for the whole ALP mass range. This search leverages dedicated kinematic variables which significantly suppress the Standard Model background. We explore the implications of our expected reach for Dark Matter freeze-out through ALP-mediated annihilations.

    hep-phJHEP(2024)·16 citations
14. 14*

    Probing a Dark Sector with Collider Physics, Direct Detection, and Gravitational Waves

    Giorgio Arcadi🇮🇹 · Glauber C. Dorsch🇧🇷 · Jacinto P. Neto🇧🇷 · Farinaldo S. Queiroz🇧🇷 · Y. M. Oviedo-Torres🇧🇷

    We assess the complementarity between colliders, direct detection searches, and gravitational wave interferometry in probing a scenario of dark matter in the early universe. The model under consideration contains a $B-L$ gauge symmetry and a vector-like fermion which acts as the dark matter candidate. The fermion induces significant a large dark matter-nucleon scattering rate, and the $Z^{\prime }$ field produces clear dilepton events at colliders. Thus, direct detection experiments and colliders severely constrain the parameter space in which the correct relic density is found in agreement with the data. Nevertheless, little is known about the new scalar responsible for breaking the $B-L$ symmetry. If this breaking occurs via a first-order phase transition at a TeV scale, it could lead to gravitational waves in the mHz frequency range detectable by LISA, DECIGO, and BBO instruments. The spectrum is highly sensitive to properties of the scalar sector and gauge coupling. We show that a possible GW detection, together with information from colliders and direct detection experiments, can simultaneously pinpoint the scalar self-coupling, and narrow down the dark matter mass where a thermal relic is viable.

    hep-phastro-ph.HEhep-thPLB(2024)·17 citations
15. 15*

    QCD on Rotating Lattice with Staggered Fermions

    Ji-Chong Yang🇨🇳 · Xu-Guang Huang🇨🇳

    We investigate the finite-temperature quantum chromodynamics (QCD) on a rotating lattice with $N_f=2+1$ staggered fermions and the projective plane boundary condition. We observe a negative rotational rigidity (defined in the main text) and a negative quark spin susceptibility associated with the chiral vortical effect. In contrast to most of the effective model predictions, we find that the chiral condensate decreases and the Polyakov loop increases with imaginary rotation, implying a rotational catalysis of chiral symmetry breaking and confinement by real rotation. We determine the phase boundaries for both chiral and confinement-deconfinement phase transitions on the ${\Omega }_I$-$T$ plane, where ${\Omega }_I$ is the imaginary angular velocity.

    ↳ hep-lathep-phhep-thnucl-th49 citations
16. 16*

    Early dark energy induced by non-linear electrodynamics

    H. B. Benaoum🇦🇪 · Luz Ángela García🇨🇴 · Leonardo Castañeda🇨🇴

    In this work, we introduce a parametrization of early dark energy that mimics radiation at early times and governs the present acceleration of the Universe. We show that such parametrization models non-linear electrodynamics in the early Universe and investigate the cosmological viability of the model. In our scenario, the early dark energy is encoded in the non-linearity of the electromagnetic fields through a parameter $\beta$ that changes the Lagrangian of the system, and the parameters ${\gamma }_s$ and $\alpha$, that define the departure from the standard model constant equation of state. We use a Bayesian method and the modular software \textsc{CosmoSIS} to find the best values for the model's free parameters with precomputed likelihoods from Planck 2018, primordial nucleosynthesis data, inferred distances from different wide galaxy surveys and luminosity distances of SNIa from Pantheon and SH0ES, such that ${\gamma }_s=$ 0.468 $\pm$ 0.026 and $\alpha =$ -0.947 $\pm$ 0.032, as opposed to $\Lambda$CDM where ${\gamma }_s=\beta =$ 0 and there is no equivalence for the $\alpha$ parameter. Our results predict an earlier formation of the structure and a shorter age of the Universe compared with the canonical cosmological model. One of the main findings of our work is that this kind of dark energy alleviates the ongoing tensions in cosmology, the Hubble tension and the so-called ${\sigma }_8$ tension, which predicted values by our model are H${}_o=$ 70.2 $\pm$ 0.9 km/s/Mpc and ${\sigma }_8=$ 0.798 $\pm$ 0.007. The reported values lie between the inferred values inferred from early and late (local) Universe observations. Future observations will shed light on the nature of the dark energy, its impact on the structure formation, and its dynamics.

    ↳ gr-qcastro-ph.COhep-phhep-th8 citations
17. 17*

    Lorentz-covariant spinor wave packet

    Kin-ya Oda🇯🇵 · Juntaro Wada🇯🇵

    We propose a novel formulation for a manifestly Lorentz-covariant spinor wave-packet basis. The traditional definition of the spinor wave packet is problematic due to its unavoidable mixing with other wave packets under Lorentz transformations. Our approach resolves this inherent mixing issue. The wave packet we develop constitutes a complete set, enabling the expansion of a free spinor field while maintaining Lorentz covariance. Additionally, we present a Lorentz-invariant expression for zero-point energy.

    ↳ hep-thhep-phPRD(2024)·6 citations
18. 18*

    Gauss-Bonnet Dark Energy and the Speed of Gravitational Waves

    José Jaime Terente Díaz🇪🇸 · Konstantinos Dimopoulos🇬🇧 · Mindaugas Karčiauskas🇪🇸 · Antonio Racioppi🇪🇪

    Gauss-Bonnet Dark Energy has been a popular model to explain the accelerated expansion of the Universe. Quite generically it also predicts the speed of gravitational waves $c_{GW}$ to be different from the speed of light. This fact alone led some authors to exclude such models in view of the new tight observational constraints on $c_{GW}$. However, the behaviour of $c_{GW}$ depends on the choice of the Gauss-Bonnet (GB) coupling function. It is possible to construct models where $c_{GW}$ is always equal to the speed of light. More generally, $c_{GW}$ is a time dependent function with instances where both speeds coincide. Nevertheless, we observe that the bound on $c_{GW}$ excludes scenarios where the GB term directly affects the expansion of the Universe, even if the constraint on the variation of the coupling function does not appear to be strong. We perform the dynamical systems analysis to see if the expansion of the Universe could be affected indirectly by modulating the behaviour of the scalar field, which modulates the GB coupling. It is shown that either the bounds on $c_{GW}$ are violated by many orders of magnitude, or it might be very difficult to find models that are consistent with other cosmological observations.

    ↳ astro-ph.COgr-qchep-phJCAP(2023)·26 citations
19. 19*

    Tunneling, Page Curve and Black Hole Information

    Chong-Sun Chu🇹🇼 · Rong-Xin Miao🇨🇳

    In a recent paper [1], we proposed that the quantum states of black hole responsible for the Bekenstein-Hawking entropy are given by Bell states of Fermi quanta in the interior of black hole. In this paper, we include the effect of tunneling on these entangled states and show that partial tunneling of these Bell states of Fermi quanta give rises to the Page curve of Hawking radiation. We also show that the entirety of information initially stored in the black hole is returned to the outside via the Hawking radiation.

    ↳ hep-thgr-qchep-ph5 citations
20. 20*

    Relativistic second-order viscous hydrodynamics from kinetic theory with extended relaxation-time approximation

    Dipika Dash🇮🇳 · Sunil Jaiswal🇮🇳 · Samapan Bhadury🇵🇱 · Amaresh Jaiswal🇮🇳

    We use the extended relaxation time approximation for the collision kernel, which incorporates a particle-energy dependent relaxation time, to derive second-order viscous hydrodynamics from the Boltzmann equation for a system of massless particles. The resulting transport coefficients are found to be sensitive to the energy dependence of the relaxation time and have significant influence on the fluid's evolution. Using the derived hydrodynamic equations, we study the evolution of a fluid undergoing (0+1)-dimensional expansion with Bjorken symmetry and investigate the fixed point structure inherent in the equations. Further, by employing a power law parametrization to describe the energy dependence of the relaxation time, we successfully reproduce the stable free-streaming fixed point for a specific power of the energy dependence. The impact of the energy-dependent relaxation time on the processes of isotropization and thermalization of an expanding plasma is discussed.

    ↳ nucl-thhep-phhep-thPRC(2023)·14 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.