Wed·Feb 7, 2024Wednesday·February 7, 2024

1. 01*

   Addendum to: Constraints on the quartic Higgs self-coupling from double-Higgs production at future hadron colliders

   Wojciech Bizoń🇵🇱 · Ulrich Haisch🇩🇪 · Luca Rottoli🇨🇭 · Zach Gillis🇺🇸 · Brian Moser🇨🇭 · Philipp Windischhofer🇺🇸

   We study inclusive double-Higgs boson production at the LHC and at the HL-LHC including variations of the trilinear and of the quartic Higgs boson self-couplings at next-to-leading order (NLO) in QCD with full top quark mass dependence. Our results include the two-loop contributions to the $gg\to HH$ amplitudes that involve a modified $h_4$ vertex calculated in arXiv:1810.04665. We present results at 13, 13.6 and 14 TeV centre-of-mass energies. The implementation of the calculation is made publicly available in the POWHEG-BOX-V2 Monte Carlo framework.

   hep-phhep-exJHEP(2024)·19 citations
2. 02*

   Measuring jet energy loss fluctuations in the quark-gluon plasma via multiparticle correlations

   Abraham Holtermann🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸 · Anne M. Sickles🇺🇸 · Xiaoning Wang🇺🇸

   The quark-gluon plasma (QGP) is a high temperature state of matter produced in the collisions of two nuclei at relativistic energies. The properties of this matter at short distance scales are probed using jets with high transverse momentum ($p_T$) resulting from quarks and gluons scattered with large momentum transfer in the earliest stages of the collisions. The Fourier harmonics for anisotropies in the high transverse momentum particle yield, $v_n(p_T)$, indicate the path length dependence of jet energy loss within the QGP. We present a framework to build off of measurements of jet energy loss using $v_n(p_T)$ by characterizing fluctuations in jet energy loss that are currently not constrained experimentally. In this paper, we utilize a set of multivariate moments and cumulants as new experimental observables to measure event-by-event fluctuations in the azimuthal anisotropies of rare probes, and compare them to the azimuthal anisotropies of soft particles. Ultimately, these fluctuations can be used to quantify the magnitude and fluctuations of event-by-event jet energy loss. We relate these quantities to existing multivariate cumulant observables, highlight their unique properties, and validate their sensitivities with a Monte Carlo simulation.

   hep-phnucl-exnucl-th5 citations
3. 03*

   Charmed hadron chemistry and flow in heavy and light ion collisions at the LHC

   Yu-Fei Liu🇨🇳 · Wen-Jing Xing🇨🇳 · Xiang-Yu Wu🇨🇦 · Shanshan Cao🇨🇳 · Guang-You Qin🇨🇳 · Shu-Qing Li🇨🇳

   We study the charmed meson and baryon production and elliptic flow in ultra-relativistic nucleus-nucleus collisions at the LHC energies. The space-time evolution of quark-gluon plasma (QGP) produced in these energetic collisions is obtained via the (3+1)-dimensional CLVisc hydrodynamics model, the heavy quark dynamics inside the QGP is simulated using an improved Langevin model that incorporates both elastic and inelastic parton energy loss processes, and the heavy quark hadronization is simulated utilizing a comprehensive coalescence-fragmentation model. Using our combined approach, we first calculate charmed hadron ratios, ${\Lambda }_c/D^0$ and $D_s/D^0$, as well as their elliptic flow ($v_2$) as a function of transverse momentum ($p_T$) for different centralities in Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$~TeV. Due to strangeness enhancement and parton coalescence effects, $D_s/D^0$ and ${\Lambda }_c/D^0$ ratios increase from peripheral to central collisions, and such centrality dependence for ${\Lambda }_c/D^0$ is stronger than $D_s/D^0$. We further predict the $p_T$ and centrality dependences of charmed hadron chemistry and $v_2$ in smaller Xe+Xe, Ar+Ar and O+O collisions at the LHC energies. Strong centrality and system size dependences for ${\Lambda }_c/D^0$ and $D_s/D^0$ ratios are observed across four collision systems. As for charmed hadron flow, both system size and collision geometry are important to understand the centrality dependence of $v_2$ in different collision systems. Our study provides a significant reference for studying heavy quark evolution and hadronizaiton in large and small systems in relativistic nuclear collisions.

   hep-phnucl-exnucl-th1 citation
4. 04*

   On the non-universality of heavy quark hadronization in elementary high-energy collisions

   Yuxuan Dai🇨🇳 · Shouxing Zhao🇨🇳 · Min He🇨🇳

   It has been traditionally hypothesized that the heavy quark (charm, $c$ and bottom, $b$) fragmentation is universal across different collision systems, based on the notion that hadronization as a soft process should occur at the characteristic non-perturbative QCD scale, ${\Lambda }_{QCD}$. However, this universality hypothesis has recently been challenged by the observation that the $c$- and $b$-baryon production relative to their meson counterparts in minimum bias proton-proton ($pp$) collisions at the LHC energies is significantly enhanced as compared to the electron-positron ($e^{+}{e}^{-}$) collisions. The conception of non-universality is unambiguously reinforced by the latest measurement of the charged-particle multiplicity dependence of the $b$-baryon-to-meson yield ratio, ${\Lambda }_b/B$, by the LHCb experiment in $\sqrt{s}=13$\,TeV $pp$ collisions at the LHC, evolving continuously from the saturation value in minimum bias $pp$ collisions toward the small value in $e^{+}{e}^{-}$ collisions as the system size gradually reduces. We address the multiplicity dependence of $b$-baryon production in the canonical statistical hadronization model with input $b$-hadron spectrum augmented with many hitherto unobserved states from quark model predictions. We demonstrate that the decreasing trend of the ${\Lambda }_b/B$ toward low multiplicities can be quantitatively understood from the canonical suppression on the yield of ${\Lambda }_b$, as caused by the requirement of strict conservation of baryon number in sufficiently small systems. We have therefore proposed a plausible scenario for understanding the origin of the non-universality of heavy quark fragmentation in elementary collisions.

   hep-phhep-exnucl-exnucl-thPRC(2024)·6 citations
5. 05*

   Entropy and multifractality in ring-like and jet-like events produced in 11.6A GeV/c ${}^{197}$Au-AgBr collisions

   Bushra Ali🇮🇳 · Sweta Singh🇮🇳 · Anuj Chandra🇮🇳 · Shakeel Ahmad🇮🇳

   Physical quantities such as, entropy, dimensions and multifractal characteristics of multiplicity distributions of charged particles produced in ${}^{197}$Au-AgBr collisions are examined and the findings are compared with the predictions of Monte Carlo model URQMD (Ultra-Relativistic Quantum Molecular Dynamics) and HIJING (Heavy Ion Jet INteraction Generator) and also with the results reported earlier in hadron-hadron and nucleus-nucleus collisions at different energies. Based on their azimuth distribution, the charged particles produced within narrow-bins exhibit two kinds of substructures, namely, ring-like and jet-like substructures. Thus, on applying the suitable criteria the two different types of events are identified and analyzed separately. It is observed that the maximum entropy production occurs around a narrow mid-rapidity region. The analyses of ring-like and jet-like events suggest that the entropy production is much larger in ring-like events as compared to that in jet-like events. Furthermore, Renyi's order-q information entropy is used to estimate the multifractal specific heat and to construct the spectrum of scaling indices. The findings reveal that the value of multifractal specific heat is higher in ring-like events as compared to that in jet-like events. The studies of generalized dimension and multifractal spectrum indicate that the multifractality is rather, more pronounced in ring-like events as compared to jet-like events. Various features of the experimental data are noticed to be nicely reproduced by the URQMD model

   hep-phIJMPE(2024)·0 citations
6. 06*

   Elucidating the nature of hidden-charm pentaquark states with spin-$\frac{3}{2}$ through their electromagnetic form factors

   U. Özdem🇹🇷

   We perform a systematic study of the electromagnetic properties of exotic states to shed light on their nature, which is still controversial and not fully understood. The magnetic dipole and higher multipole moments of a hadronic state are as fundamental a dynamical quantity as its mass, and they contain valuable information about the deep structure underlying it. In the present work, we have explored the magnetic dipole and higher multipole moments of the hidden-charm pentaquarks with quantum number $J^P=3/2^{-}$ using the QCD light-cone sum rule method and different interpolating currents. The obtained results show that different interpolating currents employed to probe pentaquarks with the same quark content produce varying results for their magnetic dipole and higher multipole moments at all. This can be interpreted to mean that there is more than one hidden-charm pentaquark with identical quark content but with different magnetic dipole and higher multipole moments. The nature, internal structure, and quark-gluon configurations of these states can be better understood by studying their electromagnetic properties.

   hep-phhep-exhep-latPLB(2024)·20 citations
7. 07*

   B rare decays: theory overview

   Marco Fedele🇩🇪

   In this proceeding we will review the current theoretical status of rare $B$ decays. These decays are indeed excellent indirect probes for New Physics searches, and in the current situation where no new states have been directly observed at collider, they provide a fundamental and alternative approach in the quest for Physics beyond the Standard Model. We will focus on the following classes of decays: $B_q\to \tau \nu$, $B_q\to \mu \mu$, $B\to K^{(\ast )}\nu \bar{\nu }$, $B\to K^{(\ast )}\ell \ell$, $B_s\to \varphi \ell \ell$ and $b\to s\gamma$. The most updated Standard Model predictions will be provided, highlighting which are the main sources of uncertainty, and what is the possibility for New Physics effects when confronting the theory numbers to current experimental results.

   hep-phPoS(2024)·1 citation
8. 08*

   Probing 95 GeV Higgs in the 2HDM Type-III

   A. Belyaev🇬🇧 · R. Benbrik🇲🇦 · M. Boukidi🇲🇦 · M. Chakraborti🇬🇧 · S. Moretti🇬🇧 · S. Semlali🇬🇧

   The recent results reported by the CMS collaboration, indicating "bumps" in the $\gamma \gamma$ and $\tau \tau$ channels at $m_{\varphi }\approx 95$ GeV, provide interesting hints for new physics. We find that the lightest Higgs state of the general 2HDM (2HDM Type-III) can perfectly and simultaneously accommodate the two excesses alongside with the LEP long-standing anomaly observed in the $b\bar{b}$ channel while meeting all theoretical and experimental requirements. Furthermore, the study predicts an enhanced production process for the SM-like Higgs in $pp\to t\bar{t}{H}_{\mathrm{SM}}$, offering a testable hypothesis for future experiments.

   hep-phPoS(2024)·4 citations
9. 09*

   NNLO+PS predictions for Higgs production through bottom-quark annihilation with MINNLO${}_{\text{PS}}$

   Christian Biello🇩🇪 · Aparna Sankar🇩🇪 · Marius Wiesemann🇩🇪 · Giulia Zanderighi🇩🇪

   We consider Higgs production through bottom-quark annihilation at hadron colliders and we calculate next-to-next-to-leading-order (NNLO) corrections in QCD perturbation theory matched to parton showers (NNLO+PS). To this end, we have adapted the MINNLO${}_{\text{PS}}$ method to account for the extra scale dependence induced by an overall Yukawa coupling that is $\overline{\mathrm{MS}}$ renormalized. We compare our results against state-of-the-art fixed-order predictions at NNLO as well as resummed predictions at next-to-next-to-leading-logarithmic (NNLL) accuracy.

   hep-phEPJC(2024)·20 citations
10. 10*

    Status of R-parity violating SUSY

    Arghya Choudhury🇮🇳 · Arpita Mondal🇮🇳 · Subhadeep Mondal🇮🇳

    In this article, we discuss various phenomenological implications of possible R-parity violating (RPV) supersymmetric scenarios. In this context, the implications of both bilinear and trilinear RPV terms are reviewed from the viewpoint of neutrino physics, anomalous muon magnetic moment, different flavor observables, and collider physics. Apart from discussing the distinctive phenomenological implications of the RPV scenarios, we also survey the updated results from different studies to highlight the present status of the RPV couplings.

    hep-phhep-exEur.Phys.J.ST(2024)·16 citations
11. 11*

    $D^{+}\to K_s^0{\pi }^{+}\eta$ reaction and $a_0(980{)}^{+}$

    Natsumi Ikeno🇯🇵 · Jorgivan M. Dias🇨🇳 · Wei-Hong Liang🇨🇳 · Eulogio Oset🇪🇸

    We study the $D^{+}\to {\bar{K}}^0{\pi }^{+}\eta$ reaction where the $a_0(980)$ excitation plays a dominant role. We consider mechanisms of external and internal emission at the quark level, hadronize the $q\bar{q}$ components into two mesons and allow these mesons to undergo final state interaction where the $a_0(980)$ state is generated. While the $a_0(980)$ production is the dominant term, we also find other terms in the reaction that interfere with this production mode and, through interference with it, lead to a shape of the $a_0(980)$ significantly different from the one observed in other experiments, with an apparently much larger width.

    hep-phEPJC(2024)·10 citations
12. 12*

    Hot vs cold hidden sectors and their effects on thermal relics

    Jinzheng Li🇺🇸 · Pran Nath🇺🇸

    A variety of possibilities exist for dark matter aside from WIMPS, such as hidden sector dark matter. We discuss synchronous thermal evolution of visible and hidden sectors and show that the density of thermal relics can change $O(100\%)$ and $\Delta N_{\mathrm{eff}}$ by a factor of up to $10^5$ depending of whether the hidden sector was hot or cold at the reheat temperature. It is also shown that the approximation of using separate entropy conservation for the visible and hidden sectors is invalid even for a very feeble coupling between the two.

    hep-phLHEP(2024)·4 citations
13. 13*

    Heavy Quarkonia, Heavy-Light Tetraquarks and the Chiral Quark-Soliton Model

    Maciej Kucab🇵🇱 · Michal Praszalowicz🇵🇱

    We apply the Chiral Quark-Soliton Model used previously to describe baryons with one heavy quark to the case of heavy tetraquarks. We argue, that the model is insenstive to the nature of the heavy object bound by the soliton, i.e. to its mass and spin. Therefore, a heavy quark can be replaced by an anti-diquark without modifying the soliton background. Diquark dynamics is taken into account by means of the nonrelarivistic Schrödinger equation with the Cornell potential. We fix the Cornell potential parameters from the charmonia and bottomia spectra. We first compute $B_c$ meson masses to check our fitting procedure, and then compute diquark masses by appropriately rescaling color factors in the Cornell potential. We ten compute tetraquark masses and confirm previous findings that only $bb$ tetraquarks are bound.

    hep-phPRD(2024)·6 citations
14. 14*

    Particle physics and cosmology intertwined

    Pran Nath🇺🇸

    While the standard model accurately describes data at the electroweak scale without inclusion of gravity, beyond the standard model physics is increasingly intertwined with gravitational phenomena and cosmology. Thus gravity mediated breaking of supersymmetry in supergravity models lead to sparticles masses, which are gravitational in origin, observable at TeV scales and testable at the LHC, and supergravity also provides a candidate for dark matter, a possible framework for inflationary models and for models of dark energy. Further, extended supergravity models, and string and D-brane models contain hidden sectors some of which may be feebly coupled to the visible sector resulting in heat exchange between the visible and hidden sectors. Because of the couplings between the sectors both particle physics and cosmology are effected. The above implies that particle physics and cosmology are intrinsically intertwined in the resolution of essentially all of the cosmological phenomena such as dark matter and dark energy and in the resolution of cosmological puzzles such as Hubble tension and EDGES anomaly. Here we give a brief overview of the intertwining and implications for the discovery of sparticles, and the resolution of the cosmological anomalies and identification of dark matter and dark energy as major challenges for the coming decades.

    hep-phEntropy(2024)·4 citations
15. 15*

    Low energy effective theories of composite dark matter with real representations

    Joachim Pomper🇦🇹 · Suchita Kulkarni🇦🇹

    We consider pseudo Nambu-Goldstone bosons arising from Dirac fermions transforming in real representations of a confining gauge group as dark matter candidates. We consider a special case of two Dirac fermions and couple the resulting dark sector to the Standard Model using a vector mediator. Within this construction, we develop a consistent low energy effective theory, with special attention to Wess-Zumino-Witten term given the topologically non-trivial coset space. We furthermore include the heavier spin-0 flavour singlet state and the spin-1 vector meson multiplet, by using the Hidden Local Symmetry Lagrangian for the latter. Although we concentrate on special case of two flavours, our results are generic and can be applied to a wider variety of theories featuring real representations. We apply our formalism and comment on the effect of the flavour singlet for dark matter phenomenology. Finally, we also comment on generalisation of our formalism for higher representations and provide potential consequences of discrete symmetry breaking.

    hep-phhep-latSciPost Phys.Core(2026)·16 citations
16. 16*

    Prospects for Light Dark Matter Searches at Large-Volume Neutrino Detectors

    Bhaskar Dutta🇺🇸 · Wei-Chih Huang🇺🇸 · Doojin Kim🇺🇸 · Jayden L. Newstead🇦🇺 · Jong-Chul Park🇰🇷 · Iman Shaukat Ali🇦🇺

    We propose a new approach to search for light dark matter (DM), with keV-GeV mass, via inelastic nucleus scattering at large-volume neutrino detectors such as Borexino, DUNE, Super-K, Hyper-K, and JUNO. The approach uses inelastic nuclear scattering of cosmic-ray boosted DM, enabling a low background search for DM in these experiments. Large neutrino detectors, with higher thresholds than dark matter detectors, can be used, since the nuclear deexcitation lines are O(10) MeV. Using a hadrophilic dark-gauge-boson-portal model as a benchmark, we show that the nuclear inelastic channels generally provide better sensitivity than the elastic scattering for a large region of light DM parameter space.

    hep-phPRL(2024)·36 citations
17. 17*

    Probing the internal structures of $p\Omega$ and $\Omega \Omega$ with their production at the LHC

    Jie Pu🇨🇳 · Kai-Jia Sun🇨🇳 · Chun-Wang Ma🇨🇳 · Lie-Wen Chen🇨🇳

    The strange dibaryons $p\Omega$ (${}^5{\mathrm{S}}_2$) and $\Omega \Omega$ (${}^1{\mathrm{S}}_0$) are likely bound, existing either in molecular states like the deuteron or as more exotic compact six-quark states. Here, we investigate the production of these two dibaryons in Pb+Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV at the CERN Large Hadron Collider (LHC) within a covariant coalescence model, which employs a blast-wave-like parametrization for the phase-space configurations of constituent particles at freeze-out. For the molecular states, the $p\Omega$ and $\Omega \Omega$ are produced via $p$-$\Omega$ and $\Omega$-$\Omega$ coalescence, respectively, while for the six-quark states, they are formed through $uudsss$ and $ssssss$ coalescence. We find that the yield ratio $N_{p\Omega }/N_{\Omega }$ and $N_{\Omega \Omega }/N_{\Omega }$ have a distinct centrality dependence between the molecular and multi-quark states, thus offering a promising way for distinguishing the two states. Our results suggest that the measurements of $p\Omega$ and $\Omega \Omega$ production in relativistic heavy-ion collisions can shed light on their internal structures.

    hep-phnucl-thPRC(2024)·7 citations
18. 18*

    Collider Signatures of $W_R$ boson in the Alternative Left-Right Model

    Mariana Frank🇨🇦 · Chayan Majumdar🇬🇧 · Poulose Poulose🇮🇳 · Supriya Senapati🇺🇸 · Urjit A. Yajnik🇮🇳

    Alternative Left-Right Models offer an attractive option to left-right models. Emerging from $E_6$ grand unification, these models are consistent with light scalars which do not induce flavour-changing neutral currents due to the presence of exotic quarks. Here we investigate the signature at the LHC collider of the charged $W_R$ boson, which can be lighter than in left-right models. We include constraints from collider data and show that $W_R$ can be produced in pairs, or in conjunction with a light charged Higgs boson. The final decay products involve leptons or jets. We explore all production and decay possibilities and indicate which ones are most promising to be observed at the colliders. Our analysis shows that signals of $W_R$ bosons can be observed at the LHC at 27 TeV, some for lower luminosity, and under most favourable conditions, even at 13 TeV.

    hep-ph3 citations
19. 19*

    Lifetimes of $b$-hadrons and mixing of neutral $B$-mesons: theoretical and experimental status

    Johannes Albrecht🇩🇪 · Florian Bernlochner🇩🇪 · Alexander Lenz🇩🇪 · Aleksey Rusov🇩🇪

    In this article, we review the current status of $B$-mixing and $b$-hadron lifetimes both from experimental and theoretical points of view. Furthermore, we discuss the phenomenological potential of these observables for deepening our understanding of quantum chromodynamics (QCD) and for indirect searches for effects beyond the Standard Model (SM). In addition, we present new updated SM predictions for the mixing observables $\Delta M_{d,s}$, $\Delta {\Gamma }_{d,s}$ and $a_{fs}^{d,s}$. We conclude with an outlook on future prospects for theoretical and experimental improvements.

    hep-phEur.Phys.J.ST(2024)·57 citations
20. 20*

    Fermionic UV models for neutral triple gauge boson vertices

    Ricardo Cepedello🇪🇸 · Fabian Esser🇪🇸 · Martin Hirsch🇪🇸 · Veronica Sanz🇪🇸

    Searches for anomalous neutral triple gauge boson couplings (NTGCs) provide important tests for the gauge structure of the standard model. In SMEFT ("standard model effective field theory") NTGCs appear only at the level of dimension-8 operators. While the phenomenology of these operators has been discussed extensively in the literature, renormalizable UV models that can generate these operators are scarce. In this work, we study a variety of extensions of the SM with heavy fermions and calculate their matching to d = 8 NTGC operators. We point out that the complete matching of UV models requires four different CP-conserving d = 8 operators and that the single CPC d = 8 operator, most commonly used by the experimental collaborations, does not describe all possible NTGC form factors. Despite stringent experimental constraints on NTGCs, limits on the scale of UV models are relatively weak, because their contributions are doubly suppressed (being d = 8 and 1-loop). We suggest a series of benchmark UV scenarios suitable for interpreting searches for NTGCs in the upcoming LHC runs, obtain their current limits and provide estimates for the expected sensitivity of the high-luminosity LHC.

    hep-phhep-thJHEP(2024)·17 citations
21. 21*

    The fermion self-energy and damping rate in a hot magnetized plasma

    Ritesh Ghosh🇺🇸 · Igor A. Shovkovy🇺🇸

    We derive a general expression for the fermion self-energy in a hot magnetized plasma by using the Landau-level representation. In the one-loop approximation, the Dirac structure of the self-energy is characterized by five different functions that depend on the Landau-level index $n$ and the longitudinal momentum $p_z$. We derive general expressions for all five functions and obtain closed-form expressions for their imaginary parts. The latter receive contributions from three types of on-shell processes, which are interpreted in terms of Landau-level transitions, accompanied by a single photon (gluon) emission or absorption. By making use of the imaginary parts of the self-energy functions, we also derive the Landau-level dependent fermion damping rates ${\Gamma }_n(p_z)$ and study them numerically in a wide range of model parameters. We also demonstrate that the two-spin degeneracy of the Landau levels is lifted by the one-loop self-energy corrections. While the spin splitting of the damping rates is small, it may be important for some spin and chiral effects. We argue that the general method and the numerical results for the rates can have interesting applications in heavy-ion physics, astrophysics, and cosmology, where strongly magnetized QED or QCD plasmas are ubiquitous.

    hep-phhep-thnucl-thPRD(2024)·13 citations
22. 22*

    Minimal Production of Prompt Gravitational Waves during Reheating

    Gongjun Choi🇺🇸 · Wenqi Ke🇺🇸 · Keith A. Olive🇺🇸

    The inflationary reheating phase begins when accelerated expansion ends. As all Standard Model particles are coupled to gravity, gravitational interactions will lead to particle production. This includes the thermal bath, dark matter and gravitational radiation. Here, we compute the spectrum of gravitational waves from the inflatoncondensate during the initial phase of reheating. As particular examples of inflation, we consider the Starobinsky model and T-models, all of which are in good phenomenological agreement with CMB anisotropy measurements. The T-models are distinguished by the shape of the potential about its minimum and can be approximated by $V\sim {\varphi }^k$, where $\varphi$ is the inflaton. Interestingly, the shape of the gravitational wave spectrum (when observed) can be used to distinguish among the models considered. As we show, the Starobinsky model and T-models with $k=2$, provide very different spectra when compared to models with $k=4$ or $k>4$. Observation of multiple harmonics in the spectrum can be interpreted as a direct measurement of the inflaton mass. Furthermore, the cutoff in frequency can be used to determine the reheating temperature.

    hep-phastro-ph.COPRD(2024)·41 citations
23. 23*

    $M_{TN}$ is all you need: production of multiple semi-invisible resonances at hadron colliders

    Zhongtian Dong🇺🇸 · Kyoungchul Kong🇺🇸 · Konstantin T. Matchev🇺🇸 · Katia Matcheva🇺🇸

    The stransverse mass variable $M_{T2}$ was originally proposed for the study of hadron collider events in which $N=2$ parent particles are produced and then decay semi-invisibly. Here we consider the generalization to the case of $N\ge 3$ semi-invisibly decaying parent particles. We introduce the corresponding class of kinematic variables $M_{TN}$ and illustrate their mathematical properties. Many of the celebrated features of the $M_{T2}$ kinematic endpoint are retained in this more general case, including the ability to measure the mass of the invisible daughter particle from the stransverse mass kink. We describe and validate a numerical procedure for computing $M_{TN}$ in practice. We also identify the configurations of visible momenta which result in nontrivial ($M_{TN}\ne 0$) values, and derive a pure phase-space estimate for the fraction of such events for any $N$.

    hep-phhep-exMod.Phys.Lett.A(2024)·3 citations
24. 24*

    PandaX-xT: a Multi-ten-tonne Liquid Xenon Observatory at the China Jinping Underground Laboratory

    PandaX Collaboration: Abdusalam Abdukerim🇨🇳 · Zihao Bo🇨🇳 · Wei Chen🇨🇳 · Xun Chen🇨🇳 · Chen Cheng🇨🇳 · Zhaokan Cheng🇨🇳 · Xiangyi Cui🇨🇳 · Yingjie Fan🇨🇳 · Deqing Fang🇨🇳 · Lisheng Geng🇨🇳 · Karl Giboni🇨🇳 · Linhui Gu🇨🇳 and 80 other authors

    We propose a major upgrade to the existing PandaX-4T experiment in the China Jinping Underground Laboratory. The new experiment, PandaX-xT, will be a multi-ten-tonne liquid xenon, ultra-low background, and general-purpose observatory. The full-scaled PandaX-xT contains a 43-tonne liquid xenon active target. Such an experiment will significantly advance our fundamental understanding of particle physics and astrophysics. The sensitivity of dark matter direct detection will be improved by nearly two orders of magnitude compared to the current best limits, approaching the so-called "neutrino floor" for a dark matter mass above 10 GeV/$c^2$, providing a decisive test to the Weakly Interacting Massive Particle paradigm. By searching for the neutrinoless double beta decay of ${}^{136}$Xe isotope in the detector, the effective Majorana neutrino mass can be measured to a [10 -- 41] meV/$c^2$ sensitivity, providing a key test to the Dirac/Majorana nature of neutrino s. Astrophysical neutrinos and other ultra-rare interactions can also be measured and searched for with an unprecedented background level, opening up new windows of discovery. Depending on the findings, PandaX-xT will seek the next stage upgrade utilizing isotopic separation on natural xenon.

    ↳ hep-exastro-ph.COhep-phSCPMA(2025)·116 citations
25. 25*

    CosmoFlow: Python Package for Cosmological Correlators

    Denis Werth🇫🇷 · Lucas Pinol🇫🇷 · Sébastien Renaux-Petel🇫🇷

    Cosmological correlators hold the key to high-energy physics as they probe the earliest moments of our Universe, and conceal hidden mathematical structures. However, even at tree-level, perturbative calculations are limited by technical difficulties absent in flatspace Feynman diagrammatics. In this paper, we introduce CosmoFlow: a new accurate open source Python code that computes tree-level cosmological correlators by tracing their time flow. This code is specifically designed to offer a simple, intuitive and flexible coding environment to theorists, primordial and late-time cosmologists. It can typically serve to complement analytical computations, to provide physical intuition when studying various inflationary theories, and to obtain exact results in regimes that are analytically out of reach. This paper presents the basic structure of CosmoFlow, leads the reader through an in-depth user-guide, and illustrates how it can be used with a series of worked examples. Our hope is that this first building block sets the stage for a bank of theoretical data, which can be nurtured and enhanced collaboratively by the community. CosmoFlow is publicly available on GitHub.

    ↳ astro-ph.COgr-qchep-phhep-th+1Class.Quant.Grav.(2024)·34 citations
26. 26*

    A comparative lattice analysis of $SU(2)$ dark gluebal

    Min-Huan Chu🇨🇳 · Jun-Hui Lai🇨🇳 · Wei Wang🇨🇳 · Jialu Zhang🇨🇳 · Qianteng Zhu🇨🇳

    We study the mass and scattering cross section of $SU(2)$ glueballs as dark matter candidates using lattice simulations. We employ both naive and improved $SU(2)$ gauge actions in $3+1$ dimensions with several $\beta$ values, and adopt both the traditional Monte Carlo method and the flow-based model based on machine learning techniques to generate lattice configurations. The mass of dark scalar glueball with $J^{PC}=0^{++}$ and the NBS wave function are calculated. Using a coupling constant of $\beta =2.2$ as an illustration, we compare the dark glueball mass calculated from the configurations generated from the two methods. While consistent results can be achieved, the two methods demonstrate distinct advantages. Using the Runge-Kutta method, we extract the glueball interaction potential and two-body scattering cross section. From the observational constraints, we obtain the lower bound of the mass of scalar glueball as candidates of dark matter.

    ↳ hep-lathep-phCPC(2024)·0 citations
27. 27*

    Angular correlation and deformed Hellings-Downs curve from spin-2 ultralight dark matter

    Rong-Gen Cai🇨🇳 · Jing-Rui Zhang🇨🇳 · Yun-Long Zhang🇨🇳

    The pulsar timings are sensitive to both the nanohertz gravitational-wave background and the oscillation of ultralight dark matter. The Hellings-Downs angular correlation curve provides a criterion to search for stochastic gravitational-wave backgrounds at nanohertz via pulsar timing arrays. We study the angular correlation of the timing residuals induced by the spin-2 ultralight dark matter, which is different from the usual Hellings-Downs correlation. At a typical frequency, we show that the spin-2 ultralight dark matter can give rise to the deformation of the Hellings-Downs correlation curve induced by the stochastic gravitational wave background.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2024)·13 citations
28. 28*

    Black holes and gravitational waves from slow phase transitions

    Marek Lewicki🇵🇱 · Piotr Toczek🇵🇱 · Ville Vaskonen🇪🇪

    Slow first-order phase transitions generate large inhomogeneities that can lead to the formation of primordial black holes (PBHs). We show that the gravitational wave (GW) spectrum then consists of a primary component sourced by bubble collisions and a secondary one induced by large perturbations. The latter gives the dominant peak if $\beta /H_0<12$, impacting, in particular, the interpretation of the recent PTA data. The GW signal associated with a particular PBH population is stronger than in typical scenarios because of a negative non-Gaussianity of the perturbations and it has a distinguishable shape with two peaks.

    ↳ astro-ph.COgr-qchep-phPRL(2024)·80 citations
29. 29*

    Geometrical methods for the analytic evaluation of multiple Mellin-Barnes integrals

    Sumit Banik🇨🇭 · Samuel Friot🇫🇷

    Two recently developed techniques of analytic evaluation of multifold Mellin-Barnes (MB) integrals are presented. Both approaches rest on the definition of geometrical objets conveniently associated with the MB integrands, which can then be used along with multivariate residues analysis to derive series representations of the MB integrals. The first method is based on introducing conic hulls and considering specific intersections of the latter, while the second one rests on point configurations and their regular triangulations. After a brief description of both methods, which have been automatized in the MBConicHulls.wl Mathematica package, we review some of their applications. In particular, we show how the conic hulls method was used to obtain the first analytic calculation of complicated Feynman integrals, such as the massless off-shell conformal hexagon and double-box. We then show that the triangulation method is even more efficient, as it allows one to compute these nontrivial objects and harder ones in a much faster way.

    ↳ hep-thhep-phmath-phmath.MPActa Phys.Polon.Supp.(2024)·4 citations
30. 30*

    Classical and Quantum Computing of Shear Viscosity for $2+1D$ SU(2) Gauge Theory

    Francesco Turro🇺🇸 · Anthony Ciavarella🇺🇸 · Xiaojun Yao🇺🇸

    We perform a nonperturbative calculation of the shear viscosity for $(2+1)$-dimensional SU(2) gauge theory by using the lattice Hamiltonian formulation. The retarded Green's function of the stress-energy tensor is calculated from real time evolution via exact diagonalization of the lattice Hamiltonian with a local Hilbert space truncation, and the shear viscosity is obtained via the Kubo formula. When taking the continuum limit, we account for the renormalization group flow of the coupling but no additional operator renormalization. We find the ratio of the shear viscosity and the entropy density $\frac{\eta }{s}$ is consistent with a well-known holographic result $\frac{1}{4\pi }$ at several temperatures on a $4\times 4$ honeycomb lattice with the local electric representation truncated at $j_{\max }=\frac{1}{2}$. We also find the ratio of the spectral function and frequency $\frac{{\rho }^{xy}(\omega )}{\omega }$ exhibits a peak structure when the frequency is small. Both the exact diagonalization method and simple matrix product state classical simulation method beyond $j_{\max }=\frac{1}{2}$ on bigger lattices require exponentially growing resources. So we develop a quantum computing method to calculate the retarded Green's function and analyze various systematics of the calculation including $j_{\max }$ truncation and finite size effects, Trotter errors and the thermal state preparation efficiency. Our thermal state preparation method still requires resources that grow exponentially with the lattice size, but with a very small prefactor at high temperature. We test our quantum circuit on both the Quantinuum emulator and the IBM simulator for a small lattice and obtain results consistent with the classical computing ones.

    ↳ hep-lathep-phhep-thnucl-th+1PRD(2024)·69 citations
31. 31*

    New models of Quintessential Inflation featuring plateau and hilltop potentials

    Swagat S. Mishra🇬🇧 · Varun Sahni🇮🇳

    We introduce a new class of hilltop and plateau potentials which can successfully unify inflation and dark energy resulting in Quintessential Inflation (QI). Interestingly these new potentials are related through an inverse transformation. Namely, if $V(\varphi )=V_{0}v(\varphi )$ is a plateau potential then the inverse potential $V(\varphi )=V_0{\left[v(\varphi )\right]}^{-1}$ describes hilltop QI. A simple example is provided by the KKLT-inspired potential $v(\varphi )=\left[\frac{M^{2n}+{\varphi }^{2n}}{N^{2n}+{\varphi }^{2n}}\right]$. When $M/N\ll 1$ this potential describes plateau QI, while its inverse, ${\left[v(\varphi )\right]}^{-1}$ describes hilltop QI. Other simple models of QI arise for the class of potentials $V(\varphi )\sim \exp \left[\mp f(\varphi )\right]$, where the $-$ ($+$) sign is associated with a plateau (hilltop). A key feature of this new class of QI models is the near absence of small parameters which are usually associated with the presence of dark energy. A forecast for the gravitational wave background generated in these models is provided.

    ↳ astro-ph.COgr-qchep-phhep-thEPJC(2025)·7 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.