Tue·Jul 11, 2023Tuesday·July 11, 2023

1. 01*

   Transverse momentum dependent feed-down fractions for bottomonium production

   Jacob Boyd🇺🇸 · Sabin Thapa🇺🇸 · Michael Strickland🇺🇸

   We extract transverse momentum dependent feed-down fractions for bottomonium production using a data-driven approach. We use data published by the ATLAS, CMS, and LHCb Collaborations for sqrt(s) = 7 TeV proton-proton collisions. Based on this collected data, we produce fits to the differential cross sections for the production of both S- and P-wave bottomonium states. Combining these fits with branching ratios for excited state decays from the Particle Data Group, we compute the feed-down fractions for both the Upsilon(1S) and Upsilon(2S) as a function of transverse momentum. Our results indicate a strong dependence on transverse momentum, which is consistent with prior extractions of the feed-down fractions. When evaluated at the average momentum of the states, we find that approximately 75% of Upsilon(1S) and Upsilon(2S) states are produced directly. Our results for the transverse momentum dependent feed-down fractions are provided in tabulated form so that they can be used by other research groups.

   hep-phhep-exnucl-exnucl-thPRD(2023)·6 citations
2. 02*

   New Constraints on ALP Electron and Photon Couplings from ArgoNeuT and the MiniBooNE Beam Dump

   Francesco Capozzi🇮🇹 · Bhaskar Dutta🇺🇸 · Gajendra Gurung🇺🇸 · Wooyoung Jang🇺🇸 · Ian M. Shoemaker🇺🇸 · Adrian Thompson🇺🇸 · Jaehoon Yu🇺🇸

   Beam dumps and fixed-target experiments have been very sensitive probes of such particles and other physics beyond the Standard Model (BSM) by considering the production of new states from the primary interaction in the beam dump. In a proton beam dump, there are many secondary interactions taking place in electromagnetic showers which may be additional production channels for pseudoscalar bosons or axion-like particles (ALPs). The target-less configuration of the MiniBooNE experiment, which collected data from $1.86\times 10^{20}$ protons impinging directly on the steel beam dump, is an excellent test of sensitivity to these production channels of ALPs in the MeV mass region. Using the null observation of the MiniBooNE dump mode data, we set new constraints on ALPs coupling to electrons and photons produced through a multitude of channels and detected via both scattering and decays in the MiniBooNE detector volume. We find that the null result rules out parameter space that was previously unconstrained by laboratory probes in the 10-100 MeV mass regime for both electron and photon couplings. Lastly, we make the case for performing a dedicated analysis with 1.25$\times 10^{20}$ POT of data collected by the ArgoNeuT experiment, which we show to have complementary sensitivity and set the stage for future searches.

   hep-phhep-exPRD(2023)·47 citations
3. 03*

   High precision tests of QCD without scale or scheme ambiguities

   Leonardo Di Giustino🇮🇹 · Stanley J. Brodsky🇺🇸 · Philip G. Ratcliffe🇮🇹 · Xing-Gang Wu🇨🇳 · Sheng-Quan Wang🇨🇳

   A key issue in making precise predictions in QCD is the uncertainty in setting the renormalization scale ${\mu }_R$ and thus determining the correct values of the QCD running coupling ${\alpha }_s({\mu }_R^2)$ at each order in the perturbative expansion of a QCD observable. It has often been conventional to simply set the renormalization scale to the typical scale of the process $Q$ and vary it in the range ${\mu }_R\in [Q/2,2Q]$ in order to estimate the theoretical error. This is the practice of Conventional Scale Setting (CSS). The resulting CSS prediction will however depend on the theorist's choice of renormalization scheme and the resulting pQCD series will diverge factorially. It will also disagree with renormalization scale setting used in QED and electroweak theory thus precluding grand unification. A solution to the renormalization scale-setting problem is offered by the Principle of Maximum Conformality (PMC), which provides a systematic way to eliminate the renormalization scale-and-scheme dependence in perturbative calculations. The PMC method has rigorous theoretical foundations, it satisfies Renormalization Group Invariance (RGI) and preserves all self-consistency conditions derived from the renormalization group. The PMC cancels the renormalon growth, reduces to the Gell-Mann--Low scheme in the $N_C\to 0$ Abelian limit and leads to scale- and scheme-invariant results. The PMC has now been successfully applied to many high-energy processes. In this article we summarize recent developments and results in solving the renormalization scale and scheme ambiguities in perturbative QCD. [full abstract is in the paper].

   hep-phhep-thPPNP(2024)·27 citations
4. 04*

   Coupled-channel $D^{\ast }{K}^{\ast }-D_s^{\ast }\rho$ interactions and the origin of $T_{c\bar{s}0}(2900)$

   Man-Yu Duan🇨🇳 · Meng-Lin Du🇨🇳 · Zhi-Hui Guo🇨🇳 · En Wang🇨🇳 · Dian-Yong Chen🇨🇳

   Motivated by the recent observation of $T_{c\bar{s}0}(2900{)}^0$ and $T_{c\bar{s}0}(2900{)}^{++}$ in the $D_s\pi$ invariant mass distributions, we investigate $D^{\ast }{K}^{\ast }$ interactions in a coupled-channel approach. We show that the relativistic corrections could be significant for the energy far away from the threshold. Within the hidden local symmetry formalism, a sizable attraction interaction is found in the $J=0$ isospin triplet sector that can form a bound or a virtual state, which is consistent with the experimentally observed $T_{c\bar{s}0}(2900)$. By reproducing a $D_s^{\ast }\rho$-$D^{\ast }{K}^{\ast }$ bound/virtual state with the pole mass equal to that of the $T_{c\bar{s}0}(2900)$ measured by LHCb in the sector $(I,J)=(1,0)$, we determine the unknown parameter in the loop function, and then search for possible poles in the sectors of $I=1$, $J=1,$ 2 and $I=0$, $J=0$, 1, 2. The predicted resonances provide a useful reference for the future experimental studies of the $(C,S)=(1,1)$ systems and can be also helpful to unravel the nature of the $T_{c\bar{s}0}(2900)$.10

   hep-phhep-exPRD(2023)·26 citations
5. 05*

   Self-healing unitarity is an optical illusion

   Archit Vidyarthi🇮🇳

   Among the vast variety of proposals put forward by the community to resolve tree-level unitarity violations in Higgs inflation models, there exists the concept of self-healing. It heals the theory from supposed tree-level violations for elastic scattering processes by summing over successive vacuum polarization loop corrections. In this work, we examine this technique to check whether unitarity is indeed restored and find that there exist underlying constraints in self-healing unitarity that pose the same perturbative unitarity bounds that it was expected to heal.

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

   Four-loop splitting functions in QCD -- The gluon-to-quark case

   G. Falcioni🇬🇧 · F. Herzog (U. Edinburgh)🇬🇧 · S. Moch (U. Hamburg)🇩🇪 · A. Vogt (Liverpool U.)🇬🇧

   We have computed the even-$N$ moments $N\le 20$ of the gluon-to-quark splitting function $P_{\mathrm{qg}}$ at the fourth order of perturbative QCD via the renormalization of off-shell operator matrix elements. Our results, derived analytically for a general gauge group, agree with all results obtained for this function so far, in particular with the lowest five moments obtained via physical cross sections. Using our new moments and all available endpoint constraints, we construct approximations for the four-loop $P_{\mathrm{qg}}(x)$ that should be sufficient for a wide range of collider-physics applications. The N${}^3$LO corrections resulting from these and the corresponding quark-quark splitting functions lead to a marked improvement of the perturbative accuracy for the scale derivative of the singlet quark distribution, with effects of 1% or less at $x\gtrsim 10^{-4}$ at a standard reference scale with ${\alpha }_s=0.2$.

   hep-phPLB(2023)·71 citations
7. 07*

   Possible open charm molecular pentaquarks from ${\Lambda }_c{K}^{(\ast )}/{\Sigma }_c{K}^{(\ast )}$ interactions

   Rui Chen🇨🇳 · Qi Huang🇨🇳

   In this work, we adopt the one-boson-exchange model to study the $Y_c{K}^{(\ast )}(Y_c={\Lambda }_c,{\Sigma }_c)$ interactions. After considering both of the $S-D$ wave mixing effects and the coupled channel effects, we can predict several possible open-charm molecular pentaquarks, i.e., the single ${\Sigma }_c{K}^{\ast }$ molecular states with $I(J^P)=1/2(1/2^{-})$, $1/2(3/2^{-})$ and $3/2(1/2^{-})$, the coupled ${\Lambda }_c{K}^{\ast }/{\Sigma }_c{K}^{\ast }$ molecular states with $1/2(1/2^{-})$ and $1/2(3/2^{-})$, and the coupled ${\Sigma }_{c}K/{\Lambda }_c{K}^{\ast }/{\Sigma }_c{K}^{\ast }$ molecular state with $1/2(1/2^{-})$. Meanwhile, we extend our study to the $Y_c{\bar{K}}^{(\ast )}$ interactions, our results suggest the ${\Sigma }_c\bar{K}$ system with $I(J^P)=1/2(1/2^{-})$, the ${\Sigma }_c{\bar{K}}^{\ast }$ systems with $1/2(1/2^{-})$, $1/2(3/2^{-})$, and $3/2(3/2^{-})$, the coupled ${\Lambda }_c{\bar{K}}^{\ast }/{\Sigma }_c{\bar{K}}^{\ast }$ system with $1/2(1/2^{-})$, and the ${\Sigma }_c\bar{K}/{\Lambda }_c{\bar{K}}^{\ast }/{\Sigma }_c{\bar{K}}^{\ast }$ system with $1/2(1/2^{-})$ can be the prime molecular candidates.

   hep-phPRD(2023)·10 citations
8. 08*

   Heavy Higgs boson Searches at the LHC in the light of a Left-Right Symmetric Model

   Sanchari Bhattacharyya🇮🇳

   We investigate a Left-Right symmetric model respecting $SU(3{)}_C\otimes SU(2{)}_L\otimes U(1{)}_L\otimes SU(2{)}_R\otimes U(1{)}_R$ local gauge symmetry. We study the interactions of the heavy neutral and charged scalars of this model along with their production at the hadron collider and their subsequent decays. We analyze the collider searches of two heavy scalars, one of them is charge neutral and another one is singly charged. In both the cases we consider their associated production at the Large Hadron Collider (LHC) and finally concentrate only on the leptonic final states. We perform both cut-based and multivariate analysis using Boosted Decision Tree algorithm for 14 TeV as well as as 27 TeV LHC run with 3000 fb${}^{-1}$ integrated luminosity. As expected, the multivariate analysis shows a better signal-background discrimination compared to the cut-based analysis. In this article, we show that a charged Higgs of mass 750 GeV and 1.2 TeV can be probed with $2.77\sigma$ ($4.58\sigma$) and $1.38\sigma$ ($3.66\sigma$) significance at 14 (27) TeV run of LHC.

   hep-phPRD(2024)·3 citations
9. 09*

   Parton shower algorithm with saturation effect

   Yu Shi🇨🇳 · Shu-Yi Wei🇨🇳 · Jian Zhou🇨🇳

   We extend the previously developed small $x$ parton shower algorithm to include the kinematic constraint effect and $k_t$ resummation effect. This work enables the Monte Carlo generator to simultaneously resum large $k_t$ and small $x$ logarithms in the saturation regime for the first time. It is an important step towards simulating processes involving multiple well separated hard scales, such as di-jet production in eA collisions at EIC.

   hep-phPRD(2023)·7 citations
10. 10*

    Vacuum Integration: UV- and IR-divergencies

    I.V. Anikin🇷🇺

    In this note we present the important details regarding the massless vacuum integrations which are not outlined in the literature. In particular, it has been shown how the delta-function represents either UV-regime or IR-regime. In the case of vacuum integration, we advocate the use of sequential approach to the singular generated functions (distributions). The sequential approach is extremely useful for many practical applications, in particular, in the effective potential method.

    hep-phhep-thPhys.Part.Nucl.Lett.(2024)·0 citations
11. 11*

    Study of the gluonic quartic gauge couplings at muon colliders

    Ji-Chong Yang🇨🇳 · Yu-Chen Guo🇨🇳 · Yi-Fei Dong🇨🇳

    The potential of the muon colliders open up new possibilities for the exploration of new physics beyond the Standard Model. It is worthwhile to investigate whether muon colliders are suitable for studying gluonic quartic gauge couplings~(gQGCs), which can be contributed by dimension-8 operators in the framework of the Standard Model effective field theory, and are intensively studied recently. In this paper, we study the sensitivity of the process ${\mu }^{+}{\mu }^{-}\to jj\nu \bar{\nu }$ to gQGCs. Our result indicate that the muon colliders with c.m. energies larger than $4\mathrm{TeV}$ can be more sensitive to gQGCs than the Large Hadron Collider.

    hep-phCommun.Theor.Phys.(2023)·9 citations
12. 12*

    Heavy axions from twin dark sectors with $\bar{\theta }$-characterized mirror symmetry

    Pei-Hong Gu🇨🇳

    The QCD Lagrangian contains a CP violating gluon density term with a physical coefficient $\bar{\theta }$. The upper bound on the electric dipole moment of neutron implies that the value of $\bar{\theta }$ should be extremely small rather than the theoretically expected order of unity. The tiny $\bar{\theta }$ is commonly known as the strong CP problem. In order to solve this puzzle, we construct a $\bar{\theta }$-characterized mirror symmetry between a pair of twin dark sectors with respective discrete symmetries. By taking a proper phase rotation of dark fields, we can perfectly remove the parameter $\bar{\theta }$ from the full Lagrangian. In our scenario, the discrete symmetry breaking, which are responsible for the mass generation of dark colored fermions and dark matter fermions, can be allowed near the TeV scale. This means different phenomena from the popular axion models with high scale Peccei-Quinn global symmetry breaking.

    hep-phNPB(2024)·1 citation
13. 13*

    First-order Phase Transition interpretation of PTA signal produces solar-mass Black Holes

    Yann Gouttenoire🇮🇱

    We perform a Bayesian analysis of NANOGrav 15yr and IPTA DR2 pulsar timing residuals and show that the recently detected stochastic gravitational-wave background (SGWB) is compatible with a SGWB produced by bubble dynamics during a cosmological first-order phase transition. The timing data suggests that the phase transition would occur around QCD confinement temperature and would have a slow rate of completion. This scenario can naturally lead to the abundant production of primordial black holes (PBHs) with solar masses. These PBHs can potentially be detected by current and advanced gravitational wave detectors LIGO-Virgo-Kagra, Einstein Telescope, Cosmic Explorer, by astrometry with GAIA and by 21-cm survey.

    hep-phastro-ph.COgr-qcPRL(2023)·133 citations
14. 14*

    Quark Confinement for Multi-Quark Systems -- Application to Fully-Charmed Tetraquarks

    Guang-Juan Wang🇯🇵 · Makoto Oka🇯🇵 · Daisuke Jido🇯🇵

    A new color basis system and confinement mechanism for multi-quark systems are proposed according to the string-type picture of QCD. The color string configurations in the strong coupling QCD are implemented in the set of color basis states. The extended color Hilbert space for $QQ\bar{Q}\bar{Q}$ systems includes a ''hidden color'' state, which mixes with two-meson states $Q\bar{Q}+Q\bar{Q}$, This mixing effect leads to an attractive potential sufficient to form a bound state. We apply a realistic Hamiltonian model with the new scheme to fully charmed tetraquark states, $cc\bar{c}\bar{c}$, and find a bound and two resonant states, which could potentially correspond to the $cc\bar{c}\bar{c}$ tetraquark candidates recently observed in experiments.

    hep-phPRD(2023)·23 citations
15. 15*

    Study of the $B^{-}\to K^{-}\eta {\eta }_c$ decay due to the $D\bar{D}$ bound state

    Xin-Qiang Li🇨🇳 · Li-Juan Liu🇨🇳 · En Wang🇨🇳 · Le-Le Wei🇨🇳

    We study the $B^{-}\to K^{-}\eta {\eta }_c$ decay by taking into account the $S$-wave contributions from the pseudoscalar meson-pseudoscalar meson interactions within the unitary coupled-channel approach, where the $D\bar{D}$ bound state is dynamically generated. In addition, the contribution from the intermediate resonance $K_0^{\ast }(1430{)}^{-}$, with $K_0^{\ast }(1430{)}^{-}\to K^{-}\eta$, is also considered. Our results show that there is a clear peak around $3720$~MeV in the $\eta {\eta }_c$ invariant mass distribution, which could be associated with the $D\bar{D}$ bound state. The future precise measurements of the $B^{-}\to K^{-}\eta {\eta }_c$ process at the Belle II and LHCb experiments could be, therefore, used to check the existence of the $D\bar{D}$ bound state, and to deepen our understanding of the hadron-hadron interactions.

    hep-phPRD(2024)·11 citations
16. 16*

    Diffusion and fluctuations of open charmed hadrons in an interacting hadronic medium

    Kangkan Goswami🇮🇳 · Kshitish Kumar Pradhan🇮🇳 · Dushmanta Sahu🇮🇳 · Raghunath Sahoo🇮🇳

    Heavy quarks are excellent probes to understand the hot and dense medium formed in ultra-relativistic collisions. In a hadronic medium, studying the transport properties, e.g. the drag ($\gamma$), momentum diffusion ($B_0$), and spatial diffusion ($D_s$) coefficients of open charmed hadrons can provide useful information about the medium. Moreover, the fluctuations of charmed hadrons can help us to locate the onset of their deconfinement. In this work, we incorporate attractive and repulsive interactions in the well-established van der Waals hadron resonance gas model (VDWHRG) and study the diffusion and fluctuations of charmed hadrons. This study helps us understand the importance of interactions in the system, which affect both the diffusion and fluctuations of charmed hadrons.

    hep-phhep-exnucl-exnucl-thPRD(2023)·14 citations
17. 17*

    $\varphi (2170)$ decaying to $\varphi \pi \pi$ and $\varphi K\bar{K}$

    Yun-Hua Chen🇨🇳

    Within the framework of dispersion theory, we study the the processes $e^{+}{e}^{-}\to \varphi (2170)\to \varphi \pi \pi (K\bar{K})$. The strong pion-pion final-state interactions, especially the $K\bar{K}$ coupled channel in the $S$-wave, are taken into account in a model-independent way using the Omnès function solution. Through fitting the experimental data of the $\pi \pi$ and $\varphi \pi$ invariant mass distributions of the $e^{+}{e}^{-}\to \varphi (2170)\to \varphi {\pi }^{+}{\pi }^{-}$ process, the low-energy constants in the chiral Lagrangian are determined. The theoretical prediction for the cross sections ratio $\sigma (e^{+}{e}^{-}\to \varphi (2170)\to \varphi K^{+}{K}^{-})/\sigma (e^{+}{e}^{-}\to \varphi (2170)\to \varphi {\pi }^{+}{\pi }^{-})$ is given, which could be useful for selecting the physical solution when the fit to the $e^{+}{e}^{-}\to \varphi K^{+}{K}^{-}$ cross section distribution is available in the future. Our results suggest that above the kinematical threshold of $\varphi K\bar{K}$, the mechanism $e^{+}{e}^{-}\to \varphi K^{+}{K}^{-}$ with the kaons rescattering to a pion pair plays an important role in the $e^{+}{e}^{-}\to \varphi {\pi }^{+}{\pi }^{-}$ transition.

    hep-phhep-exnucl-thUniverse(2023)·2 citations
18. 18*

    Full event simulation of Photoproduction at NLO QCD in Sherpa

    Peter Meinzinger🇬🇧

    Photoproduction is an important mode for the production of jets and electro-weak particles at lepton--lepton and lepton--hadron colliders and allows for interesting studies of exclusive production at hadron--hadron colliders. In this talk, I will review recent efforts of extending the Sherpa event generator to include the calculation of photoproduction cross sections for electron and proton beams, including the simulation of underlying events. The framework is validated using data of jet production at the HERA and LEP experiments and lepton production at the LHC. I will discuss advances towards achieving matched NLO accuracy and fully capturing the dynamics of inclusive and exclusive photoproduction at different colliders.

    hep-ph0 citations
19. 19*

    Toward a generative modeling analysis of CLAS exclusive $2\pi$ photoproduction

    T. Alghamdi🇺🇸 · Y. Alanazi🇺🇸 · M. Battaglieri🇮🇹 · L. Bibrzycki🇵🇱 · A. V. Golda🇷🇺 · A. N. Hiller Blin🇩🇪 · E. L. Isupov🇷🇺 · Y. Li🇨🇳 · L. Marsicano🇮🇹 · W. Melnitchouk🇺🇸 · V. I. Mokeev🇺🇸 · G. Montana🇺🇸 and 4 other authors

    AI-supported algorithms, particularly generative models, have been successfully used in a variety of different contexts. In this work, we demonstrate for the first time that generative adversarial networks (GANs) can be used in high-energy experimental physics to unfold detector effects from multi-particle final states, while preserving correlations between kinematic variables in multidimensional phase space. We perform a full closure test on two-pion photoproduction pseudodata generated with a realistic model in the kinematics of the Jefferson Lab CLAS g11 experiment. The overlap of different reaction mechanisms leading to the same final state associated with the CLAS detector's nontrivial effects represents an ideal test case for AI-supported analysis. Uncertainty quantification performed via bootstrap provides an estimate of the systematic uncertainty associated with the procedure. The test demonstrates that GANs can reproduce highly correlated multidifferential cross sections even in the presence of detector-induced distortions in the training datasets, and provides a solid basis for applying the framework to real experimental data.

    hep-phhep-exnucl-thPRD(2023)·15 citations
20. 20*

    Distinguishing between Dirac and Majorana neutrinos using temporal correlations

    Bhavya Soni🇮🇳 · Sheeba Shafaq · Poonam Mehta🇮🇳

    In the context of two flavour neutrino oscillations, it is understood that the $2\times 2$ mixing matrix is parameterized by one angle and a Majorana phase. However, this phase does not impact the oscillation probabilities in vacuum or in matter with constant density. Interestingly, the Majorana phase becomes relevant when we describe neutrino oscillations along with neutrino decay. This is due to the fact that effective Hamiltonian has Hermitian and anti-Hermitian components which cannot be simultaneously diagonalized (resulting in decay eigenstates being different from the mass eigenstates). We consider the $\mathcal{P}\mathcal{T}$ symmetric non-Hermitian Hamiltonian describing two flavour neutrino case and study the violation of Leggett-Garg Inequalities (LGI) in this context for the first time. We demonstrate that temporal correlations in the form of LGI allow us to probe whether neutrinos are Dirac or Majorana. We elucidate the role played by the mixing and decay parameters on the extent of violation of LGI. We emphasize that for optimized choice of parameters, the difference in $K_4$ ($K_3$) for Dirac and Majorana case is $\sim 15\%$ ($\sim 10\%$).

    hep-phquant-ph9 citations
21. 21*

    Exploring nonstandard quark interactions through solar neutrino studies

    Ilídio Lopes🇵🇹

    We investigate the effects of a Non-Standard Interaction (NSI) extension of the standard model of particle physics on solar neutrino flavour oscillations. This NSI model introduces a $U_{Z^{\prime }}(1)$ gauge symmetry through a $Z^{\prime }$ boson that mixes with the photon, creating a neutral current between active neutrinos and matter fields via a unique coupling to up and down quarks. The interaction is defined by a single parameter, ${\zeta }_o$, which is related to the $Z^{\prime }$ boson's mass $m_{Z^{\prime }}$ and coupling constant $g_{Z^{\prime }}$. Notably, this model relaxes the bounds on Coherent Elastic Neutrino-Nucleus Scattering experiments and fits the experimental values of the anomalous magnetic dipole moment of the muon. In this study, we use solar neutrino measurements and an up-to-date standard solar model to evaluate the neutrino flavour oscillations and assess the constraints on ${\zeta }_o$. Our study indicates that the NSI model aligns with the current solar neutrino data when ${\zeta }_o$ is between $-0.7$ and $0.002$. These models have ${\chi }_{\nu }^2$ values equal to or better than the standard neutrino flavor oscillation model, which stands at a ${\chi }_{\nu }^2$ of 3.12. The best NSI model comes with a ${\zeta }_o$ value of -0.2 and a ${\chi }_{\nu }^2$ of 2.96. Including extra data from the Darwin experiment in our analysis refines the range of ${\zeta }_o$ values from $-0.7$ to $0.002$, down to $-0.5$ to $-0.002$. These results hint at the possible existence of novel interactions, given that NSI models achieve a comparable or superior fit to the solar neutrino data when contrasted with the prevailing standard model of neutrino flavour oscillation.

    hep-phastro-ph.SRhep-exPRD(2023)·0 citations
22. 22*

    NANOGrav spectral index $\gamma =3$ from melting domain walls

    E. Babichev🇫🇷 · D. Gorbunov🇷🇺 · S. Ramazanov🇨🇿 · R. Samanta🇨🇿 · A. Vikman🇨🇿

    We discuss cosmic domain walls described by a tension red-shifting with the expansion of the Universe. These melting domain walls emit gravitational waves with the low-frequency spectral shape ${\Omega }_{gw}\propto f^2$ corresponding to the spectral index $\gamma =3$ favoured by the recent NANOGrav 15 yrs data. We discuss a concrete high-energy physics scenario leading to such a melting domain wall network in the early Universe. This scenario involves a feebly coupled scalar field, which can serve as a promising dark matter candidate. We identify parameters of the model matching the gravitational wave characteristics observed in the NANOGrav data. The dark matter mass is pushed to the ultra-light range below $10^{-11}-10^{-12}\text{eV}$ which is accessible through planned observations thanks to the effects of superradiance of rotating black holes.

    hep-phastro-ph.COhep-thPRD(2023)·87 citations
23. 23*

    Singling out SO(10) GUT models using recent PTA results

    Stefan Antusch🇨🇭 · Kevin Hinze🇨🇭 · Shaikh Saad🇨🇭 · Jonathan Steiner🇨🇭

    In this work, we construct promising model building routes towards SO(10) GUT inflation and examine their ability to explain the recent PTA results hinting at a stochastic gravitational wave (GW) background at nanohertz frequencies. We consider a supersymmetric framework within which the so-called doublet-triplet splitting problem is solved without introducing fine-tuning. Additionally, realistic fermion masses and mixings, gauge coupling unification, and cosmic inflation are incorporated by utilizing superfields with representations no higher than the adjoint representation. Among the three possible scenarios, two of these cases require a single adjoint Higgs field, and do not lead to cosmic strings. In contrast, the third scenario featuring two adjoints, can lead to a network of metastable cosmic strings that generates a GW background contribution compatible with the recent PTA findings and testable by various ongoing and upcoming GW observatories.

    hep-phPRD(2023)·89 citations
24. 24*

    Properties of the ${\eta }_q$ leading-twist distribution amplitude and its effects to the $B/D^{+}\to {\eta }^{(\prime )}{\ell }^{+}{\nu }_{\ell }$ decays

    Dan-Dan Hu (Chongqing University)🇨🇳 · Xing-Gang Wu (Chongqing University)🇨🇳 · Hai-Bing Fu (Guizhou MinZu University)🇨🇳 · Tao Zhong (Guizhou MinZu University)🇨🇳 · Zai-Hui Wu (Guizhou MinZu University)🇨🇳 · Long Zeng (Chongqing University)🇨🇳

    The ${\eta }^{(\prime )}$-mesons in the quark-flavor basis are mixtures of two mesonic states $|{\eta }_q⟩=|\bar{u}u+\bar{d}d⟩/\sqrt{2}$ and $|{\eta }_s⟩=|\bar{s}s⟩$. In the previous work, we have made a detailed study on the ${\eta }_s$ leading-twist distribution amplitude. As a sequential work, in the present paper, we fix the ${\eta }_q$ leading-twist distribution amplitude by using the light-cone harmonic oscillator model for its wave function and by using the QCD sum rules within the QCD background field to calculate its moments. The input parameters of ${\eta }_q$ leading-twist distribution amplitude ${\varphi }_{2;{\eta }_q}$ at an initial scale ${\mu }_0\sim 1$ GeV are then fixed by using those moments. The sum rules for the $0_{\mathrm{th}}$-order moment can also be used to fix the magnitude of ${\eta }_q$ decay constant, which gives $f_{{\eta }_q}=0.141\pm 0.005$ GeV. As an application of the present derived ${\varphi }_{2;{\eta }_q}$, we calculate the transition form factors $B(D{)}^{+}\to {\eta }^{(\prime )}$ by using the QCD light-cone sum rules up to twist-4 accuracy and by including the next-to-leading order QCD corrections to the twist-2 part, and then fix the related CKM matrix element and the decay width for the semi-leptonic decays $B(D{)}^{+}\to {\eta }^{(\prime )}{\ell }^{+}{\nu }_{\ell }$.

    hep-phEPJC(2024)·12 citations
25. 25*

    Baryogenesis and Dark Matter in the Mirror Twin Higgs

    Pedro Bittar🇧🇷 · Gustavo Burdman🇧🇷 · Larissa Kiriliuk🇧🇷

    We consider a natural asymmetric dark matter (ADM) model in the mirror twin Higgs (MTH). We show that it is possible to obtain the correct dark matter (DM) abundance when a twin baryon is the DM without the need of explicit breaking of the MTH ${\mathbb{Z}}_2$ symmetry in the dimensionless couplings (i.e. without hard ${\mathbb{Z}}_2$ breaking). We illustrate how this is possible in a specific baryogenesis setup, which also leads to ADM. In the simplest scenario we obtain $m_{\mathrm{DM}}\sim O(1)$GeV, just above the proton mass. We show estimates for direct detection rates at present and future experiments.

    hep-phhep-exJHEP(2023)·13 citations
26. 26*

    The Mikheyev-Smirnov-Wolfenstein Matter Potential at the One-loop Level in the Standard Model

    Jihong Huang🇨🇳 · Shun Zhou🇨🇳

    When neutrinos are propagating in ordinary matter, their coherent forward scattering off background particles results in the so-called Mikheyev-Smirnov-Wolfenstein (MSW) matter potential, which plays an important role in neutrino flavor conversions. In this paper, we present a complete one-loop calculation of the MSW matter potential in the Standard Model (SM). First, we carry out the one-loop renormalization of the SM in the on-shell scheme, where the electromagnetic fine-structure constant $\alpha$, the weak gauge-boson masses $m_W^{}$ and $m_Z^{}$, the Higgs-boson mass $m_h^{}$ and the fermion masses $m_f^{}$ are chosen as input parameters. Then, the finite corrections to the scattering amplitudes of neutrinos with the electrons and quarks are calculated, and the one-loop MSW matter potentials are derived. Adopting the latest values of all physical parameters, we find that the relative size of one-loop correction to the charged-current matter potential of electron-type neutrinos or antineutrinos turns out to be $6\%$, whereas that to the neutral-current matter potential of all-flavor neutrinos or antineutrinos can be as large as $8\%$. The calculations are also performed in the $\overline{\mathrm{MS}}$ scheme and compared with previous results in the literature.

    hep-phhep-exPRD(2023)·11 citations
27. 27*

    Metastable cosmic strings

    Wilfried Buchmuller🇩🇪 · Valerie Domcke🇨🇭 · Kai Schmitz🇩🇪

    Many symmetry breaking patterns in grand unified theories (GUTs) give rise to cosmic strings that eventually decay when pairs of GUT monopoles spontaneously nucleate along the string cores. These strings are known as metastable cosmic strings and have intriguing implications for particle physics and cosmology. In this article, we discuss the current status of metastable cosmic strings, with a focus on possible GUT embeddings and connections to inflation, neutrinos, and gravitational waves (GWs). The GW signal emitted by a network of metastable cosmic strings in the early universe differs, in particular, from the signal emitted by topologically stable strings by a suppression at low frequencies. Therefore, if the underlying symmetry breaking scale is close to the GUT scale, the resulting GW spectrum can be accessible at current ground-based interferometers as well as at future space-based interferometers, such as LISA, and at the same time account for the signal in the most recent pulsar timing data sets. Metastable cosmic strings thus nourish the hope that future GW observations might shed light on fundamental physics close to the GUT scale.

    hep-phastro-ph.COgr-qcJCAP(2023)·78 citations
28. 28*

    Supercooling in Radiative Symmetry Breaking: Theory Extensions, Gravitational Wave Detection and Primordial Black Holes

    Alberto Salvio🇮🇹

    First-order phase transitions, which take place when the symmetries are predominantly broken (and masses are then generated) through radiative corrections, produce observable gravitational waves and primordial black holes. We provide a model-independent approach that is valid for large-enough supercooling to quantitatively describe these phenomena in terms of few parameters, which are computable once the model is specified. The validity of a previously-proposed approach of this sort is extended here to a larger class of theories. Among other things, we identify regions of the parameter space that correspond to the background of gravitational waves recently detected by pulsar timing arrays (NANOGrav, CPTA, EPTA, PPTA) and others that are either excluded by the observing runs of LIGO and Virgo or within the reach of future gravitational wave detectors. Furthermore, we find regions of the parameter space where primordial black holes produced by large over-densities due to such phase transitions can account for dark matter. Finally, it is shown how this model-independent approach can be applied to specific cases, including a phenomenological completion of the Standard Model with right-handed neutrinos and gauged $B-L$ undergoing radiative symmetry breaking.

    hep-phastro-ph.COastro-ph.HEgr-qc+1JCAP(2023)·106 citations
29. 29*

    Remarks on the Axion Domain Wall Problem

    Michael Dine🇺🇸

    Theories in which the Peccei-Quinn phase transition occurs after inflation tend to suffer from problematic domain walls. One possible solution involves a small, explicit breaking ot the symmetry. But this raises other potential issues. We review some aspects of axion domain walls, focussing especially on this proposed solution. We argue, in disagreement with some recent literature, that there is little axion radiation from the system until the domains actually collapse. The same applies to gravitational waves and electromagnetic radiation. The final stages of the collapse yields small numbers of extremely energetic axions, which interact only rarely with ordinary matter, and are thus relatively harmless. We then note that, if one accepts a remarkable coincidence, this solution can be acceptable. We consider a possible explanation of the required coincidence

    hep-phhep-th6 citations
30. 30*

    Sphaleron in the Higgs Triplet Model

    Jiahang Hu🇨🇳 · Bingrong Yu🇨🇳 · Shun Zhou🇨🇳

    The Higgs triplet model (HTM) extends the Standard Model (SM) by one complex triplet scalar (also known as the type-II seesaw model), offering a simple and viable way to account for nonzero neutrino masses. On the other hand, the nontrivial couplings of the triplet to the gauge fields and to the SM Higgs field are expected to influence the topological vacuum structure of the SM, and consequently, the energy and the field configuration of the electroweak sphaleron. The sphaleron process plays a crucial role in dynamically generating the baryon asymmetry of the Universe. In this work, we study the vacuum structure of the gauge and Higgs fields and calculate the saddle-point sphaleron configuration in the HTM. The coupled nonlinear equations of motion of the sphaleron are solved using the spectral method. We find the inclusion of the triplet scalar could in principle significantly change the sphaleron energy compared with the SM. Nevertheless, at zero temperature, the current stringent experimental constraint on the vacuum expectation value of the triplet suppresses the difference. Interestingly, we find that there still exists some narrow parameter space where the sphaleron energy can be enhanced up to $30\%$ compared with the SM case.

    hep-phastro-ph.COhep-thJHEP(2023)·4 citations
31. 31*

    Quark/Gluon Discrimination and Top Tagging with Dual Attention Transformer

    Minxuan He🇨🇳 · Daohan Wang🇰🇷

    Jet tagging is a crucial classification task in high energy physics. Recently the performance of jet tagging has been significantly improved by the application of deep learning techniques. In this study, we introduce a new architecture for jet tagging: the Particle Dual Attention Transformer (P-DAT). This novel transformer architecture stands out by concurrently capturing both global and local information, while maintaining computational efficiency. Regarding the self attention mechanism, we have extended the established attention mechanism between particles to encompass the attention mechanism between particle features. The particle attention module computes particle level interactions across all the particles, while the channel attention module computes attention scores between particle features, which naturally captures jet level interactions by taking all particles into account. These two kinds of attention mechanisms can complement each other. Further, we incorporate both the pairwise particle interactions and the pairwise jet feature interactions in the attention mechanism. We demonstrate the effectiveness of the P-DAT architecture in classic top tagging and quark-gluon discrimination tasks, achieving competitive performance compared to other benchmark strategies.

    hep-phEPJC(2023)·26 citations
32. 32*

    Towards $gg\to HH$ at next-to-next-to-leading order: light-fermionic three-loop corrections

    Joshua Davies🇬🇧 · Kay Schönwald🇨🇭 · Matthias Steinhauser🇩🇪

    We consider light-fermion three-loop corrections to $gg\to HH$ using forward scattering kinematics in the limit of a vanishing Higgs boson mass, which covers a large part of the physical phase space. We compute the form factors and discuss the technical challenges. The approach outlined in this letter can be used to obtain the full virtual corrections to $gg\to HH$ at next-to-next-to-leading order.

    hep-phPLB(2023)·28 citations
33. 33*

    Exploring high scale seesaw models through a supersymmetric portal

    Yi Liu🇬🇧 · Stefano Moretti🇬🇧 · Harri Waltari🇸🇪

    The seesaw scale is a priori unknown. If the seesaw scale is low, one may directly look for the new particles predicted by seesaw models. If the seesaw scale is high, such an approach is unfeasible. We show that in some supersymmetric seesaw models the large Yukawa couplings of high scale seesaw models leave their fingerprints to Higgs-slepton couplings and that this can result in decays of the type ${\tilde{\nu }}_2\to {\tilde{\nu }}_{1}h$ in Type-I and Type-III seesaw models and ${\tilde{\ell }}_2^{\pm }\to {\tilde{\ell }}_1^{\pm }h$ in the latter. Unfortunately the current exclusion bounds make it impossible to see a significant signal even at the High-Luminosity phase of the LHC. In this paper, we highlight that the High-Energy phase of the LHC (with $\sqrt{s}=27$~TeV) could afford one with some sensitivity to those in the single lepton channel.

    hep-ph3 citations
34. 34*

    Exponential Resummation of QCD at finite chemical potential

    Sabarnya Mitra🇮🇳

    A comprehensive study of the QCD phase diagram is one of the challenging and open problems in high energy physics. Having significant astrophysical implications, this is also important in constructing the chronological evolution of the universe. With this aim, this thesis describes the behaviour of thermodynamic observables like pressure and number density with changing chemical potential $\mu$, through the method of an unbiased exponential resummation of lower order Taylor series of these observables at a finite $\mu$. We address the problem of biased estimates, which manifest uncontrollably in exponential resummation and which become severe in the domain of large values, higher orders of $\mu$ and also in observables which are higher $\mu$ derivatives of the thermodynamic potential. We show that our new formalism of unbiased exponential resummation can eliminate these biased estimates exactly upto a given order of $\mu$, and can capture important contributions of higher order Taylor series for all our working temperatures starting from hadronic phase to the plasma phase, including the crossover region. We also demonstrate that this new formalism is highly efficient in saving appreciable computational time and storage space for computations.

    hep-phhep-latnucl-exnucl-th2 citations
35. 35*

    The ${\mathbb{Z}}_2$ anomaly in some chiral gauge theories

    Stefano Bolognesi🇮🇹 · Kenichi Konishi🇮🇹 · Andrea Luzio🇮🇹

    We revisit the simplest Bars-Yankielowicz (BY) model (the $\psi \eta$ model), starting from a model with an additional Dirac pair of fermions in the fundamental representation, together with a complex color-singlet scalar $\varphi$ coupled to them through a Yukawa interaction. This model possesses a color-flavor-locked 1-form ${\mathbb{Z}}_N$ symmetry, due to the intersection of the color $SU(N)$ and two nonanomalous $U(1)$ groups. In the bulk, the model reduces to the $\psi \eta$ model studied earlier when $\varphi$ acquires a nonzero vacuum expectation value and the extra fermions pair up, get massive and decouple (thus we will call our extended theory as the ``X-ray model"), while it provides a regularization of the ${\mathbb{Z}}_2$ fluxes needed to study the ${\mathbb{Z}}_2$ anomaly. The anomalies involving the 1-form ${\mathbb{Z}}_N$ symmetry reduce, for $N$ even, exactly to the mixed ${\mathbb{Z}}_2$ anomaly found earlier in the $\psi \eta$ model. The present work is a first significant step to clarify the meaning of the mixed ${\mathbb{Z}}_2-[{\mathbb{Z}}_N^{(1)}{]}^2$ anomaly found in the $\psi \eta$ and in other BY and Georgi-Glashow type $SU(N)$ models with even $N$.

    ↳ hep-thhep-lathep-phJHEP(2023)·9 citations
36. 36*

    Hot QCD Phase Diagram From Holographic Einstein-Maxwell-Dilaton Models

    Romulo Rougemont🇧🇷 · Joaquin Grefa🇺🇸 · Mauricio Hippert🇺🇸 · Jorge Noronha🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸 · Israel Portillo🇺🇸 · Claudia Ratti🇺🇸

    In this review, we provide an up-to-date account of quantitative holographic descriptions of the strongly coupled quark-gluon plasma (QGP) produced in heavy-ion collisions, based on the class of gauge-gravity Einstein-Maxwell-Dilaton (EMD) models. Holography is employed to tentatively map the QCD phase diagram at finite temperature onto a dual theory of charged, asymptotically AdS black holes in 5D. With a quantitative focus on the hot QCD phase diagram, the EMD models reviewed are adjusted to describe lattice results for the finite-temperature QCD equation of state, with 2+1 flavors and physical quark masses, at zero chemical potential and vanishing electromagnetic fields. The predictive power of EMD models is tested by quantitatively comparing their predictions for the hot QCD equation of state at nonzero baryon density and the corresponding state-of-the-art lattice QCD results. The shear and bulk viscosities predicted by these EMD models are also compared to the corresponding profiles favored by the latest phenomenological multistage models describing different heavy-ion data. We report preliminary results from a Bayesian analysis which provide systematic evidence that lattice results at finite temperature and zero baryon density strongly constrains the free parameters of EMD models. Remarkably, the set of parameters constrained by lattice results at zero chemical potential produces EMD models in quantitative agreement with lattice QCD results also at finite baryon density. We also review results for equilibrium and transport properties from magnetic EMD models, describing the QGP at finite temperatures and magnetic fields. Finally, we provide a critical assessment of the main limitations and drawbacks of the holographic models reviewed in the present work, and point out some perspectives we believe are of fundamental importance for future developments.

    ↳ nucl-thhep-phhep-thPPNP(2024)·86 citations
37. 37*

    Slow-roll inflation and growth of perturbations in Kaniadakis modification of Friedmann cosmology

    Gaetano Lambiase🇮🇹 · Giuseppe Gaetano Luciano🇪🇸 · Ahmad Sheykhi🇮🇷

    Kaniadakis entropy is a one-parameter deformation of the classical Boltzmann-Gibbs-Shannon entropy, arising from a self-consistent relativistic statistical theory. Assuming a Kaniadakis-type generalization of the entropy associated with the apparent horizon of Friedmann-Robertson-Walker (FRW) Universe and using the gravity-thermodynamics conjecture, a new cosmological scenario is obtained based on the modified Friedmann equations. By employing such modified equations, we analyze the slow-roll inflation, driven by a scalar field with power-law potential, at the early stages of the Universe. We explore the phenomenological consistency of this model by computation of the scalar spectral index and tensor-to-scalar ratio. Comparison with the latest Planck data allows us to constrain Kaniadakis parameter to $\kappa \lesssim \mathcal{O}(10^{-12}÷10^{-11})$, which is discussed in relation to other observational bounds in the past literature. We also disclose the effects of Kaniadakis correction term on the growth of perturbations at the early stages of the Universe by employing the spherically symmetric collapse formalism in the linear regime of density perturbations. We find out that the profile of density contrast is non-trivially affected in this scenario. Interestingly enough, we observe that increasing Kaniadakis parameter $\kappa$ corresponds to a faster growth of perturbations in a Universe governed by the corrected Friedmann equations. Finally, we comment on the consistency of the primordial power spectrum for scalar perturbations with the best data-fit provided by Planck.

    ↳ gr-qchep-phhep-thEPJC(2023)·46 citations
38. 38*

    Experimental signatures of an alternative supersymmetry

    Roland E. Allen🇺🇸

    There are at least three physical arguments for some form of supersymmetry, based on experiment and observation, but conventional supersymmetry (SUSY) has not been observed up to surprisingly high experimental limits. Here we consider a radically different version, with initial bosonic fields in $32=16+\overline{16}$ (primitive sfermion) and $10=5+\overline{5}$ (primitive Higgs-related) representations of Spin(10) which do not satisfy Lorentz invariance. In the extremely early universe there is a reformation of these fields to achieve a stable Lorentz-invariant vacuum with two varieties of physical scalar-boson fields -- standard fields $\varphi$ and fields $\phi$ of a new kind. There are then two possible scenarios: If sfermion fields are in the $\varphi$ sector, the present description leads back to standard physics, including the standard model, SO(10) grand unification, and conventional SUSY. But if sfermion fields belong to the $\phi$ sector, the predictions for production and decays of sparticles are dramatically different, potentially explaining their previous nonobservation. The masses of scalar bosons are still protected from enormous radiative corrections, gauge unification can be achieved, and there is a lowest-mass superpartner as a dark matter candidate -- although it is presumed to be less abundant than the $\approx 70$ GeV candidate we introduced earlier in this same general context. Calculations by Shankar, Tallman, and Martinez in separate papers explore the possibilities for detection in future colliders, beginning with the high-luminosity LHC.

    ↳ physics.gen-phhep-ph1 citation
39. 39*

    Hyperon polarization and its relation with directed flow in high-energy nuclear collisions

    Ze-Fang Jiang🇨🇳 · Xiang-Yu Wu🇨🇳 · Shanshan Cao🇨🇳 · Ben-Wei Zhang🇨🇳

    We investigate the hyperon polarization and its relation with the directed flow of the quark-gluon plasma (QGP) in non-central Au+Au collisions at $\sqrt{s_{\text{NN}}}=27$ GeV. A modified 3-dimensional (3D) Glauber model is developed and coupled to a (3+1)-D viscous hydrodynamic evolution of the QGP. Within this framework, we obtain a satisfactory simultaneous description of the directed flow of identified particles and $\Lambda$ polarization, and show sensitivity of polarization to both the tilted geometry and the longitudinal flow profile of the QGP. A non-monotonic transverse momentum dependence of the $\Lambda$ polarization is found in our calculation, which is absent from hydrodynamic simulation using other initialization methods and can be tested by future experimental data with higher precision. The relation between the global polarization and directed flow of $\Lambda$ is explored as the longitudinal flow field or the medium deformation varies. Due to the common origin of these two observables, their combination may provide a more stringent constraint on the initial condition of the QGP.

    ↳ nucl-thhep-phPRC(2023)·20 citations
40. 40*

    Bootstrapping the Chiral Anomaly at Large $N_c$

    Teng Ma🇮🇱 · Alex Pomarol🇪🇸 · Francesco Sciotti🇪🇸

    The bootstrap approach (demanding consistency conditions to scattering amplitudes) has shown to be quite powerful to tightly constrain gauge theories at large $N_c$. We extend previous analysis to scattering amplitudes involving pions and external gauge bosons. These amplitudes allow us to access the chiral anomaly and connect low-energy physical quantities to UV properties of the theory. In particular, we are able to obtain an analytic bound on the chiral anomaly coefficient as a function of the pion dipole polarizabilities. This bound can be useful for holographic models whose dual UV completions are not known, and provide a consistency condition to lattice simulations.

    ↳ hep-thhep-lathep-phJHEP(2023)·48 citations
41. 41*

    Atmospheric muons at PeV energies in radio neutrino detectors

    Lilly Pyras🇩🇪 · Christian Glaser🇸🇪 · Steffen Hallmann🇩🇪 · Anna Nelles🇩🇪

    Experiments seeking to detect radio emission stemming from neutrino interactions will soon reach sensitivities that bring a detection within reach. Since experiments like RNO-G or the future IceCube-Gen2 target more than an order of magnitude more effective volume than existing experiments, the renewed and detailed study of rare backgrounds is needed. In this paper, we study the potential background from energy losses of highly energetic atmospheric muons. Due to both limited experimental measurements and limited modeling in hadronic interaction models, the expected event rate is subject to large uncertainties. Here, we estimate rate predictions and their uncertainties for different models and instrumental parameters. We also study possible routes towards mitigation of the muon background, such as parent air shower detection, and illustrate what is needed to make the first measurement of the prompt muon flux at energies above 10 PeV.

    ↳ astro-ph.HEhep-phJCAP(2023)·8 citations
42. 42*

    Constraining Electromagnetic Signals from Black Holes with Hair

    Nicole R. Crumpler (William H. Miller III Department of Physics and Astronomy, Johns Hopkins University Baltimore, MD USA)🇺🇸

    We constrain a broad class of "hairy" black hole models capable of directly sourcing electromagnetic radiation during a binary black hole merger. This signal is generic and model-independent since it is characterized by the black hole mass ($M$) and the fraction of that mass released as radiation ($ϵ$). For field energy densities surpassing the Schwinger limit, this mechanism triggers pair-production to produce a gamma-ray burst. By cross-referencing gravitational wave events with gamma-ray observations, we place upper bounds of $ϵ<10^{-5}-10^{-4}$ for $10-50$ $M_{\odot }$ black holes depending on the black hole mass. We discuss the weak detection of a gamma-ray burst following GW150914 and show that this event is consistent with rapid electromagnetic emission directly from a "hairy" black hole with $ϵ\sim 10^{-7}-10^{-6}$. Below the Schwinger limit, ambient charged particles are rapidly accelerated to nearly the speed of light by the strong electromagnetic field. For 1-50 $M_{\odot }$ black holes and $ϵ$ ranging from $10^{-20}$ to $10^{-7}$, the typical proton energies are $\sim 20$ GeV-20 TeV and electron energies are $\sim 0.01-10$ GeV. At these energies, cosmic ray protons and electrons quickly diffuse into the Milky Way's background magnetic field, making it difficult to identify a point source producing them. Overall, constraining $ϵ$ in this less energetic regime becomes difficult and future constraints may need to consider specific models of "hairy" black holes.

    ↳ astro-ph.HEhep-phPRD(2023)·3 citations
43. 43*

    Comparison of Point Cloud and Image-based Models for Calorimeter Fast Simulation

    Fernando Torales Acosta🇺🇸 · Vinicius Mikuni🇺🇸 · Benjamin Nachman🇺🇸 · Miguel Arratia🇺🇸 · Bishnu Karki🇺🇸 · Ryan Milton🇺🇸 · Piyush Karande🇺🇸 · Aaron Angerami🇺🇸

    Score based generative models are a new class of generative models that have been shown to accurately generate high dimensional calorimeter datasets. Recent advances in generative models have used images with 3D voxels to represent and model complex calorimeter showers. Point clouds, however, are likely a more natural representation of calorimeter showers, particularly in calorimeters with high granularity. Point clouds preserve all of the information of the original simulation, more naturally deal with sparse datasets, and can be implemented with more compact models and data files. In this work, two state-of-the-art score based models are trained on the same set of calorimeter simulation and directly compared.

    ↳ cs.LGhep-exhep-phnucl-ex+1JINST(2024)·45 citations
44. 44*

    Multi-fractional instantons in $SU(N)$ Yang-Mills theory on the twisted ${\mathbb{T}}^4$

    Mohamed M. Anber🇬🇧 · Erich Poppitz🇨🇦

    We construct analytical self-dual Yang-Mills fractional instanton solutions on a four-torus ${\mathbb{T}}^4$ with 't Hooft twisted boundary conditions. These instantons possess topological charge $Q=\frac{r}{N}$, where $1\le r<N$. To implement the twist, we employ $SU(N)$ transition functions that satisfy periodicity conditions up to center elements and are embedded into $SU(k)\times SU(\ell )\times U(1)\subset SU(N)$, where $\ell +k=N$. The self-duality requirement imposes a condition, $k{L}_1{L}_2=r\ell L_3{L}_4$, on the lengths of the periods of ${\mathbb{T}}^4$ and yields solutions with abelian field strengths. However, by introducing a detuning parameter $\Delta \equiv (r\ell L_3{L}_4-k{L}_1{L}_2)/\sqrt{L_1{L}_2{L}_3{L}_4}$, we generate self-dual nonabelian solutions on a general ${\mathbb{T}}^4$ as an expansion in powers of $\Delta$. We explore the moduli spaces associated with these solutions and find that they exhibit intricate structures. Solutions with topological charges greater than $\frac{1}{N}$ and $k\ne r$ possess non-compact moduli spaces, along which the $O(\Delta )$ gauge-invariant densities exhibit runaway behavior. On the other hand, solutions with $Q=\frac{r}{N}$ and $k=r$ have compact moduli spaces, whose coordinates correspond to the allowed holonomies in the $SU(r)$ color space. These solutions can be represented as a sum over $r$ lumps centered around the $r$ distinct holonomies, thus resembling a liquid of instantons. In addition, we show that each lump supports $2$ adjoint fermion zero modes.

    ↳ hep-thhep-lathep-phJHEP(2023)·22 citations
45. 45*

    Quantum thermodynamics of de Sitter space

    Robert Alicki🇵🇱 · Gabriela Barenboim🇪🇸 · Alejandro Jenkins🇵🇱

    We consider the local physics of an open quantum system embedded in an expanding three-dimensional space $\mathbf{x}$, evolving in cosmological time $t$, weakly coupled to a massless quantum field. We derive the corresponding Markovian master equation for the system's nonunitary evolution and show that, for a de Sitter space with Hubble parameter $h=$ const., the background fields act as a physical heat bath with temperature $T_{\mathrm{dS}}=h/2\pi$. The energy density of this bath obeys the Stefan-Boltzmann law ${\rho }_{\mathrm{dS}}\propto h^4$. We comment on how these results clarify the thermodynamics of de Sitter space and support previous arguments for its instability in the infrared. The cosmological implications are considered in an accompanying letter.

    ↳ gr-qchep-phhep-thquant-phPRD(2023)·24 citations
46. 46*

    The irreversible relaxation of inflation

    Robert Alicki🇵🇱 · Gabriela Barenboim🇪🇸 · Alejandro Jenkins🇵🇱

    Based on the results of a previous analysis of the Markovian master equation for the irreversible evolution of an open system embedded in de Sitter space, we include in the cosmological Friedmann equations a contribution from the presence of a physical bath at temperature $T_{\mathrm{dS}}=h/2\pi$, where $h$ is the Hubble parameter. We show that this provides a mechanism for the irreversible relaxation of the cosmological constant and a graceful exit to inflation, without need for subsequent reheating. Thermal particle production during inflation gives adiabatic, Gaussian, and approximately scale-invariant cosmological perturbations. We thus obtain the main features of inflation without any inflaton potential. To clarify the thermodynamic interpretation of these results, we consider the analogy of this irreversible relaxation to superfluorescence in quantum optics.

    ↳ gr-qcastro-ph.COhep-phhep-thPLB(2025)·16 citations
47. 47*

    Inconsistency with De Sitter Spacetime in a New Approach to Gravitational Particle Production

    Mark P. Hertzberg🇺🇸 · Abraham Loeb🇺🇸

    We study a claimed new mechanism for particle production and black hole evaporation through a spatially dependent temperature. This new temperature is comparable to the Hawking result near the black hole, but is very small far away, and therefore could be a small correction. Here we apply the proposed reasoning to the case of de Sitter space, finding that it over predicts the de Sitter temperature of a minimally coupled scalar by factor of $\approx 4.3$ and over predicts the particle production rate by a factor of $\approx 52$. For non-minimally coupled scalars, it has other various problems; it predicts a negative particle production for conformal, or nearly conformal, coupled scalars; it predicts unsuppressed productions of heavy scalars. This all demonstrates an inconsistency in the proposed formalism.

    ↳ gr-qcastro-ph.HEhep-phhep-thPhys.Dark Univ.(2025)·6 citations
48. 48*

    Viscosity and diffusion in life processes and tuning of fundamental constants

    K Trachenko🇬🇧

    Viewed as one of the grandest questions in modern science, understanding fundamental physical constants has been discussed in high-energy particle physics, astronomy and cosmology. Here, I review how condensed matter and liquid physics gives new insights into fundamental constants and their tuning. This is based on two observations: first, cellular life and the existence of observers depend on viscosity and diffusion. Second, the lower bound on viscosity and upper bound on diffusion are set by fundamental constants, and I briefly review this result and related recent developments in liquid physics. I will subsequently show that bounds on viscosity, diffusion and the newly introduced fundamental velocity gradient in a biochemical machine can all be varied while keeping the fine-structure constant and the proton-to-electron mass ratio intact. This implies that it is possible to produce heavy elements in stars but have a viscous planet where all liquids have very high viscosity (for example that of tar or higher) and where life may not exist. Knowing the range of bio-friendly viscosity and diffusion, we will be able to calculate the range of fundamental constants which favor cellular life and observers and compare this tuning with that discussed in high-energy physics previously. This invites an inter-disciplinary research between condensed matter physics and life sciences, and I formulate several questions that life science can address. I finish with a conjecture of multiple tuning and an evolutionary mechanism.

    ↳ physics.bio-phcond-mat.softcond-mat.stat-mechhep-ph+1Rept.Prog.Phys.(2023)·4 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.