Mon·May 20, 2024Monday·May 20, 2024

1. 01*

   Analytical insights into the interplay of momentum, multiplicity and the speed of sound in heavy-ion collisions

   Gabriel Soares Rocha🇺🇸 · Lorenzo Gavassino🇺🇸 · Mayank Singh🇺🇸 · Jean-François Paquet🇺🇸

   We introduce a minimal model of ultracentral heavy-ion collisions to study the relation between the speed of sound of the produced plasma and the final particles' energy and multiplicity. We discuss how the particles' multiplicity $N_{\text{tot}}$ and average energy $E_{\text{tot}}/N_{\text{tot}}$ is related to the speed of sound $c_s$ by $c_s^2=d\ln (E_{\text{tot}}/N_{\text{tot}})/d\ln N_{\text{tot}}$ if the fluid is inviscid, its speed of sound is constant and all final particles can be measured. We show that finite rapidity cuts on the particles' multiplicity $N$ and energy $E$ introduce corrections between $c_s^2$ and $d\ln (E/N)/d\ln N$ that depend on the system's lifetime. We study analytically these deviations with the Gubser hydrodynamic solution, finding that, for ultrarelativistic bosons, they scale as the ratio of the freezeout temperature $T_{\mathrm{FO}}$ over the maximum initial temperature of the fluid $T_0$; the non-thermodynamic aspect of these corrections is highlighted through their dependence on the system's initial conditions.

   hep-phnucl-thPRC(2024)·8 citations
2. 02*

   Limits on the parameter space of (3+2) sterile neutrino scenario by IceCube data

   Emilse Cabrera🇧🇷 · Arman Esmaili🇧🇷 · Alexander A. Quiroga🇧🇷

   The neutrino sector of the standard model of particles can contain more than one sterile neutrino states. Generally, existence of more sterile states leads to better, or at least equally good, fit to the short baseline anomalous data due to the larger number of parameters and interferences which create features in the oscillation pattern. However, for experiments like IceCube, where the sterile states distort the oscillation pattern of high energy atmospheric neutrinos through parametric and MSW resonances, addition of more sterile states leads to a more intense effect. Although the limits on one additional sterile neutrino state by IceCube data have been studied in the literature, bounds on the models with more sterile states are lacking. We analyze the one-year data set of atmospheric neutrinos collected by IceCube during the 2011-2012 and derive the limits on the parameter space of (3+2) scenario with two sterile neutrino states, taking into account the relevant systematic and statistical uncertainties and atmospheric neutrino flux variants. To facilitate the joint analysis of IceCube and short baseline data, we provide the table of ${\chi }^2$ values from IceCube's data analysis as function of the parameters.

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

   Study of Neutrino Phenomenology and $0\nu \beta \beta$ Decay using Polyharmonic $Maa\beta$ Forms

   Bhabana Kumar🇮🇳 · Mrinal Kumar Das🇮🇳

   In this study, we explore the application of the ${\Gamma }_3$ modular group, which is isomorphic to the $A_4$ symmetric group in developing a model for neutrino mass. We realized a non-supersymmetric left-right asymmetric model incorporating modular symmetry, where the modular forms consist of both holomorphic and non-holomorphic components and the Yukawa couplings expressed through polyharmonic $Maa\beta$ forms. To effectively implement the extended see-saw process in this model, we introduce one fermion singlet for each generation. We compute the effective mass and the associated half-life of $0\nu \beta \beta$ by accounting for both standard and non-standard contributions. Additionally, our study investigates the non-unitary effects and CP-violation arising from non-unitarity in this context. The model predicts values for the sum of neutrino masses and neutrino oscillation parameters are constraints with experiments. Furthermore, it yields satisfactory results in calculating the effective mass and half-life of $0\nu \beta \beta$ decay. These findings highlight the possibility and benefit of employing modular symmetry in neutrino mass model construction.

   hep-phInt.J.Mod.Phys.A(2025)·11 citations
4. 04*

   Progress Towards Two-loop QCD Corrections to $pp\to t\bar{t}j$

   Simon Badger🇮🇹

   We present the status of on-going efforts to compute the two-loop virtual corrections to $pp\to t\bar{t}j$ in the leading colour approximation. We review the recent study of the master integrals and their differential equations and present some ideas on modern techniques that can be applied to provide complete evaluation of helicity amplitudes containing information on top quark decays in the narrow width approximation.

   hep-ph1 citation
5. 05*

   Gravitational wave in a filtered vector dark matter model

   Mojtaba Hosseini🇮🇷 · Seyed Yaser Ayazi🇮🇷 · Ahmad Mohamadnejad🇮🇷

   We consider a first order phase transition (FOPT) for a Vector Dark Matter (VDM) in the early universe in which its mass may partially arise from such mechanism in the hidden sector. We calculate the ratio of VDM that may enter the bubble for various bubble wall velocities as well as various nucleation temperatures that produce the measured dark matter relic abundance via bubble filtering. In the following, we focus on gravitational wave (GW) signals which produced by FOPT and show that it can be detectable at the DECIGO, TianQin, LISA and Ultimate-DECIGO (UDECIGO) experiments.

   hep-phPhys.Dark Univ.(2025)·4 citations
6. 06*

   Open bottom production at NNLO+NNLL

   Terry Generet🇬🇧

   In this talk, I presented some of the results of the first calculation of open bottom production at hadron colliders at NNLO+NNLL, i.e. a next-to-next-to-leading-order calculation that resums collinear logarithms at next-to-next-to-leading-logarithmic accuracy. This new computation achieves significantly reduced theory errors compared to previous calculations, with errors of just a few percent at high transverse momenta. These results are compared to data from many measurements performed at the Tevatron, where lower-order predictions have previously been found to underestimate the cross section. To perform such comparisons, the hadronisation and decay of the $b$-quark are included in the theory calculation where needed, yielding predictions for a wide range of final states.

   hep-ph0 citations
7. 07*

   Light from darkness: history of a hot dark sector

   Rupert Coy🇧🇪 · Jean Kimus🇧🇪 · Michel H.G. Tytgat🇧🇪

   We study a scenario in which the expansion of the Early Universe is driven by a hot hidden sector (HS) with an initial temperature $T^{\prime }$ that is significantly higher than that of the visible sector (VS), $T^{\prime }\gg T$. The latter is assumed to be made of Standard Model (SM) particles and our main focus is on the possibility that dark matter (DM) is part of the dominant HS and that its abundance is set by secluded freeze-out. In particular, we study the subsequent evolution and fate of the DM companion particle after freeze-out all the way toward reheating of the VS. To make this scenario more concrete, we work within dark QED, a framework in which the DM is a Dirac fermion and its companion, a massive dark photon; coupling between the SM and HS is through kinetic mixing. We provide a detailed and comprehensive numerical and analytical analysis of the different regimes of reheating of the VS. Extending and complementing the work of Coy et al on the``Domain of thermal dark matter candidates", we use our results to explore the viable parameter space of both the DM matter particle and its companion, here the dark photon. We show that current and future fixed target experiments can probe scenarios along which the expansion was driven by relativistic DM photons, a scenario dubbed relativistic reheating. We also set new bounds on the maximal temperature ratio $T^{\prime }/T$ and argue for an extension of the domain toward very large DM masses, $m_{\mathrm{dm}}\sim 10^{11}$ GeV. These are possible assuming that DM annihilation is bounded by unitarity and that reheating of the VS occurs just before big bang nucleosynthesis. We also discuss some possible implications for (and constraints on) baryogenesis, including simple leptogenesis mechanisms, and how they may set additional constraints on the domain of DM candidates.

   hep-phastro-ph.COJCAP(2025)·8 citations
8. 08*

   Probing the heavy neutrino hypothesis

   Xabier Marcano🇪🇸

   There is a strong experimental program searching for massive sterile neutrinos. Here we focus on the heavy regime above the GeV scale, where their existence can be probed in either high-energy colliders or in high-precision facilities. We first review the current experimental status at colliders, showing that the LHC already improves LEP results for mixings to electrons and muons, while mixings to taus remain challenging at a hadron collider. We also discuss the importance of exploring both lepton number violating and conserving signals, as well as different flavor channels. Finally, we present the latest global analysis of electroweak precision and flavor observables, showing that the intensity frontier provides the strongest constraints for heavy neutrino masses above the electroweak scale.

   hep-phhep-ex3 citations
9. 09*

   $K\to \pi \nu \bar{\nu }$ spectra and NA62 interpretation

   Martin Gorbahn🇬🇧 · Ulserik Moldanazarova🇬🇧 · Kai Henryk Sieja🇩🇪 · Emmanuel Stamou🇩🇪 · Mustafa Tabet🇩🇪

   Using the measured and projected invisible mass spectrum of the $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ mode, we determine the current and future constraints within the model-independent framework of the weak effective theory at dimension-six. We work in two different operator bases depending whether neutrinos are Majorana or Dirac fermions. This makes it possible to transparently incorporate mass effects of additional sterile neutrinos for all operators.

   hep-ph0 citations
10. 10*

    Quantum entanglement between neutrino eigenstates in the presence of the subsequent phase shift of the neutrino oscillations

    Hoda Abdolalizade · Ekrem Aydiner🇹🇷

    In this Letter, using von Neumann entropy we examine the entanglement entropy for the neutrino oscillations in the presence of the subsequent phase shift. We numerically show that the entanglement entropy for the subsequent periods of the two-flavor neutrino oscillations increases asymmetrically with time depending on the space-time deformation. We also explored the obtained results for the three-flavor neutrino oscillations to show that this result is also valid for the three-flavor neutrino oscillations. These results, obtained for the first time in this Letter, are quite different from the computing for the standard neutrino oscillation theory. We concluded that these interesting results play an important role in the cosmology.

    hep-phhep-thEPL(2024)·3 citations
11. 11*

    Bispectrum at 1-loop in the Effective Field Theory of Inflation

    Supritha Bhowmick🇮🇳 · Diptimoy Ghosh🇮🇳 · Farman Ullah🇮🇳

    In this paper we compute 1-loop corrections to the bispectrum in the decoupling limit of the Effective Field Theory of Inflation (EFToI). We regulate the divergences by employing dimensional regularization and work in $d=3+\delta$ dimensions. We find that the final results feature analytic structures of the form $\log \left(k_i/k_T\right)$ and $\log \left(H/\mu \right)$, where $H$ is the Hubble parameter and $\mu$ is the renormalisation scale. An interesting outcome of our calculations is that unlike the 1-loop correction to the power-spectrum computed in arXiv:0912.2734 the unrenormalised answers always produce unphysical logarithms of co-moving momenta. These unphysical logarithms are cancelled only after renormalisation. We expect this to be a generic feature for loop computations unless there is some cancellation as in the previously computed 1-loop result for the power-spectrum.

    ↳ hep-thgr-qchep-phJHEP(2024)·12 citations
12. 12*

    Charm lifetime measurements at Belle II

    A. J. Schwartz🇺🇸

    We report precision measurements of lifetimes of charmed mesons and baryons performed by the Belle II experiment. Specifically, we measure $D_s^{+}$, $D^{+}$, $D^0$, ${\Lambda }_c^{+}$, and ${\Omega }_c^0$ lifetimes. Our results for $\tau (D_s^{+})$, $\tau (D^{+})$, $\tau (D^0)$, and $\tau ({\Lambda }_c^{+})$ are the world's most precise; our result for $\tau ({\Omega }_c^0)$ confirms that the ${\Omega }_c^0$ lifetime is longer than that of the ${\Lambda }_c^{+}$ and the ${\Xi }_c^0$.

    ↳ hep-exhep-ph1 citation
13. 13*

    Renormalizability of the leading order operator for neutrinoless double beta decay with the effects of finite nucleon size

    Tai-Xing Liu🇨🇳 · Ri-Guang Huang🇨🇳 · Dong-Liang Fang🇨🇳

    The fundamental process of neutrinoless double beta decay, $nn\to pp{e}^{-}{e}^{-}$, dominated by the exchange of light Majorana neutrinos, is studied in the framework of chiral effective field theory. Considering neutrinos as virtual states, we evaluate the contributions of finite nucleon size to the transition amplitude in a non-perturbative manner, as opposed to expanding these effects in powers of momentum. Based on the nucleon form factors expressed in terms of the dipole and Kelly parametrizations, we find that, at the leading order, the present scheme could renormalize the amplitude in the context of the standard mechanism and provide predictions consistent with the previous investigations. Consequently, we argue that the impact of the effects of finite nucleon size on the amplitude is comparable to that of the leading-order contact term introduced in [Phys. Rev. Lett.120, 202001(2018)] in a perturbative scheme. Our results provide not only a benchmark calculation for the transition amplitude between two schemes but also evidence for the reasonableness of non-perturbative treatment for the effects of finite nucleon size in conventional nuclear many-body methods.

    ↳ nucl-thhep-phPRC(2025)·2 citations
14. 14*

    Double Inflation in Classically Conformal $B-L$ Model

    Anish Ghoshal🇵🇱 · Nobuchika Okada🇺🇸 · Arnab Paul🇮🇳 · Digesh Raut🇺🇸

    It has recently been shown in Ref. [1] that the double-inflation scenario based on the Coleman-Weinberg potential can successfully generate primordial black holes (PBHs) with the inflationary predictions consistent with the Planck measurements. These PBHs can play the role of dark matter in our universe. In this paper, we propose the classically conformal minimal $B-L$ model as an ultra-violet (UV) completion of the scenario. In our model, the $B-L$ Higgs field is identified with the inflaton and the electroweak symmetry breaking is triggered by the radiative $B-L$ symmetry breaking with the Coleman-Weinberg potential. We show that this UV completion leads to a viable cosmological history after the double inflaton: the universe is reheated via inflaton decay into right-handed neutrinos whose mass is determined consistently by a relation between the number of e-folds and reheating temperature. Using the general parameterization for neutrino Dirac Yukawa couplings through the seesaw mechanism and the neutrino oscillation data, we also show that the observed baryon asymmetry of the universe is successfully reproduced by either resonant leptogenesis or non-thermal leptogenesis. Based on the scalar power spectrum shown in Ref. [1], we evaluate the scalar induced gravitational wave spectrum, which can be tested by various proposed gravitational wave observatories like BBO, DECIGO etc.

    ↳ astro-ph.COhep-phhep-thJCAP(2025)·3 citations
15. 15*

    Centre vortex geometry at finite temperature

    Jackson A. Mickley🇦🇺 · Waseem Kamleh🇦🇺 · Derek B. Leinweber🇦🇺

    The geometry of centre vortices is studied in $\mathrm{SU}(3)$ gauge theory at finite temperature to capture the key structural changes that occur through the deconfinement phase transition. Visualisations of the vortex structure in temporal and spatial slices of the lattice reveal a preference for the vortex sheet to align with the temporal dimension above the critical temperature. This is quantified through a correlation measure. A collection of vortex statistics, including vortex and branching point densities, and vortex path lengths between branching points, are analysed to highlight internal shifts in vortex behaviour arising from the loss of confinement. We find the zero-temperature inclination of branching points to cluster at short distances vanishes at high temperatures, embodying a rearrangement of branching points within the vortex structure. These findings establish the many aspects of centre vortex geometry that characterise the deconfinement phase transition in pure gauge theory.

    ↳ hep-lathep-phPRD(2024)·13 citations
16. 16*

    STOLAS: STOchastic LAttice Simulation of cosmic inflation

    Yurino Mizuguchi🇯🇵 · Tomoaki Murata🇯🇵 · Yuichiro Tada🇯🇵

    We develop a C++ package of the STOchastic LAttice Simulation (STOLAS) of cosmic inflation. It performs the numerical lattice simulation in the application of the stochastic-$\delta N$ formalism. STOLAS can directly compute the three-dimensional map of the observable curvature perturbation without estimating its statistical properties. In its application to two toy models of inflation, chaotic inflation and Starobinsky's linear-potential inflation, we confirm that STOLAS is well-consistent with the standard perturbation theory. Furthermore, by introducing the importance sampling technique, we have success in numerically sampling the current abundance of primordial black holes in a non-perturbative way. The package is available at https://github.com/STOchasticLAtticeSimulation/STOLAS_dist.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2024)·30 citations
17. 17*

    Proceedings of the talk "Study of CP violation in charm meson decays" for XXX Epiphany conference

    Aleksei Chernov🇵🇱

    Basic idea of $CP$ violation and its importance for cosmology, Standard Model and possible New Physics are introduced. Recent (2019) discovery of CP violation in charm in the $\Delta A_{CP}$ between $D^0\to K^{-}{K}^{+}$ and $D^0\to {\pi }^{+}{\pi }^{-}$ decay channels and evidence for direct CP violation in $D^0\to {\pi }^{-}{\pi }^{+}$ decays in 2023 is discussed. Motivation and brief outline for search of CP violation in the $D^0\to V\gamma$, where $V=\varphi ,{\rho }^0,{\bar{K}}^{\ast 0}$ decays is given.

    ↳ hep-exhep-ph1 citation
18. 18*

    The Convergence Problem Of Gradient Expansion In The Relaxation Time Approximation

    Reghukrishnan Gangadharan🇮🇳 · Victor Roy🇮🇳

    We obtain a formal integral solution to the 3+1 D Boltzmann Equation in relaxation time approximation. The gradient series obtained from this integral solution contains exponentially decaying non-hydrodynamic terms. It is shown that this gradient expansion can have a finite radius of convergence under certain assumptions of analyticity. We then argue that, in the relaxation time model, proximity to local thermal equilibrium is not necessary for the system to be described by hydrodynamic equations.

    ↳ nucl-thhep-phhep-thmath-ph+1PRD(2025)·4 citations
19. 19*

    Gravitational waves from low-scale cosmic strings

    Kai Schmitz🇩🇪 · Tobias Schröder🇩🇪

    Cosmic strings are a common prediction in many grand unified theories and a promising source of stochastic gravitational waves (GWs) from the early Universe. In this paper, we point out that the GW signal from cosmic strings produced at a comparatively low energy scale, $v\lesssim 10^9\text{GeV}$, exhibits several novel features that are not present in the case of high-scale cosmic strings. Our findings notably include (i) a sharp cutoff frequency $f_{\mathrm{cut}}$ in the GW spectrum from the fundamental oscillation mode on closed string loops and (ii) an oscillating pattern in the total GW spectrum from all oscillation modes whose local minima are located at integer multiples of $f_{\mathrm{cut}}$. These features reflect the fact that string loops produced in the early Universe fail to shrink to zero size because of GW emission within the age of the Universe, if their tension is low enough. In addition, they offer an exciting opportunity to directly probe the discrete spectrum of oscillation modes on closed string loops in GW observations. For strings produced at a scale $v\sim 10^9\text{GeV}$, the novel features in the GW spectrum are within the sensitivity reach of future experiments such as BBO and DECIGO.

    ↳ astro-ph.COgr-qchep-phPRD(2024)·16 citations
20. 20*

    Fingerprints of a Non-Inflationary Universe from Massive Fields

    Jerome Quintin🇨🇦 · Xingang Chen🇺🇸 · Reza Ebadi🇺🇸

    We construct explicit models of classical primordial standard clocks in an alternative to inflation, namely the slowly contracting ekpyrotic scenario. We study the phenomenology of massive spectator fields added to a state-of-the-art ekpyrotic model, with coupling functions that allow for these heavy fields to be classically excited while the background is slowly contracting. We perform numerical computations of the corrections to the scalar primordial power spectrum and compare with analytical estimates. Our full numerical results reveal so-called clock signals, sharp feature signals, as well as signals that link the two together. The models are found to predict oscillatory features that are resolutely different from what is calculated in inflation, and thus, such features represent unique fingerprints of a slowly contracting universe. This confirms the capability of primordial standard clocks to model-independently discriminate among very early universe scenarios.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2024)·18 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.