Tue·Aug 24, 2021Tuesday·August 24, 2021

1. 01*

   Higgs boson decay to the pair of S- and P-wave $B_c$ mesons

   R.N. Faustov (FRC CSC RAS)🇷🇺 · F.A. Martynenko (Samara U.)🇷🇺 · A.P. Martynenko (Samara U.)🇷🇺

   We investigate the rare production of the pair of $S-$ and $P-$ wave $B_c$-meson in the Higgs boson decay in the perturbative Standard Model and relativistic quark model. Relativistic amplitudes and decay widths are constructed with the account of the relative motion of heavy quarks forming $B_c$ mesons. When constructing the Higgs boson decay amplitudes, the method of projection operators on the $S-$ and $P-$wave states of quarks is used. Relativistic corrections are expressed in terms of special relativistic parameters and are calculated numerically in the quark model. The dependence of the decay widths of the Higgs boson on various sources of relativistic corrections is investigated.

   hep-phEPJA(2022)·14 citations
2. 02*

   A determination of the longitudinal structure function $F_L$ from the parametrization of $F_2$ based on the Laplace transformation

   G.R.Boroun🇮🇷

   I calculate the longitudinal structure function, using Laplace transform techniques, from the parametrization of the structure function $F_2(x,Q^2)$ and its derivative at low values of the Bjorken variable $x$. I consider the effect of the charm quark mass to the longitudinal structure function, which leads to rescaling variable for $n_f=4$. The results are compared with the H1 collaboration data and the CTEQ-Jefferson Lab (CJ) collaboration [Phys.Rev.D {\bf93}, 114017 (2016)] parametrization model. The obtained results with the Bjorken variable of $x$ are found to be comparable with the results L.P.Kaptari et al. [Phys.Rev.D {\bf99}, 096019 (2019)] which is based on the Mellin transform techniques.

   hep-phEur.Phys.J.Plus(2022)·3 citations
3. 03*

   Primordial Black Holes from Confinement

   Gia Dvali🇩🇪 · Florian Kuhnel🇩🇪 · Michael Zantedeschi🇩🇪

   A mechanism for the formation of primordial black holes is proposed. Here, heavy quarks of a confining gauge theory produced by de Sitter fluctuations are pushed apart by inflation and get confined after horizon re-entry. The large amount of energy stored in the colour flux tubes connecting the quark pair leads to black-hole formation. These are much lighter and can be of higher spin than those produced by standard collapse of horizon-size inflationary overdensities. Other difficulties exhibited by such mechanisms are also avoided. Phenomenological features of the new mechanism are discussed as well as accounting for both the entirety of the dark matter and the supermassive black holes in the galactic centres. Under proper conditions, the mechanism can be realised in a generic confinement theory, including ordinary QCD. We discuss a possible string-theoretic realisation via $D$-branes. Interestingly, for conservative values of the string scale, the produced gravity waves are within the range of recent NANOGrav data. Simple generalisations of the mechanism allow for the existence of a significant scalar component of gravity waves with distinct observational signatures.

   hep-phastro-ph.COhep-thPRD(2021)·70 citations
4. 04*

   3-dimensional QCD phase diagram with pion condensate in the NJL model

   Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Guang-Xiong Peng🇨🇳

   With the isovector coupling constants adjusted to reproduce the physical pion mass and lattice QCD results in baryon-free quark matter, we have carried out rigourous calculations for the pion condensate in the 3-flavor Nambu-Jona-Lasinio model, and studied the 3-dimensional QCD phase diagram. With the increasing isospin chemical potential ${\mu }_I$, we have observed two nonzero solutions of the pion condensate at finite baryon chemical potentials ${\mu }_B$, representing respectively the pion superfluid phase and the Sarma phase, and their appearance and disappearance correspond to a second-order (first-order) phase transition at higher (lower) temperatures $T$ and lower (higher) ${\mu }_B$. Calculations by assuming equal constituent mass of $u$ and $d$ quarks would lead to large errors of the QCD phase diagram within ${\mu }_B\in (500,900)$ MeV, and affect the position of the critical end point.

   hep-phnucl-thPRD(2021)·17 citations
5. 05*

   Statistical Uncertainties of the $N_{\text{DW}}=1$ QCD Axion Mass Window from Topological Defects

   Sebastian Hoof🇩🇪 · Jana Riess🇩🇪 · David J. E. Marsh🇬🇧

   We review results from QCD axion string and domain wall simulations and propagate the associated uncertainties, including QCD uncertainties, into the calculation of the axion relic density. We compare two different sets of studies and, using cosmological constraints, perform statistical inference on the axion mass window in the post-inflationary Peccei-Quinn symmetry breaking scenario. For dark matter axions in recent simulations inferring a moderately infrared-dominated spectrum, this leads to a median dark matter axion mass of 0.50 meV, while the 95% credible interval at highest posterior density is between 0.48 and 0.52 meV. For alternative simulations including in addition string-domain wall decays (but with different overall inference on the spectrum), these numbers are 0.22 meV and [0.16, 0.27] meV. Relaxing the condition that axions are all of the dark matter, the axion mass window is completed by an upper bound of around 80 meV, which comes from dark radiation constraints. This confirms that the axion mass can be constrained rather precisely regarding statistical uncertainties and further calls for a more detailed analysis of the various sources of systematic uncertainties plaguing the simulations.

   hep-phastro-ph.COCosmol.Nongalactic Astrophys.(2022)·13 citations
6. 06*

   Chiral vortical catalysis

   Yin Jiang🇨🇳

   Gluon interaction introduces remarkable corrections to the magnetic polarization effects on the chiral fermions, which is known as the inverse magnetic catalysis. It is a natural speculation that the vorticity, which has many similar properties as magnetic field, would bring non-negligible contribution to the chiral rotational suppression. Using the intuitive semi-classical background field method we studied the rotation dependence of the effective strong interaction coupling. Contrary to the magnetic field case the rotation increases the effective coupling which leads to slowing down the condensate melting procedure with temperature. This could be named as the chiral vortical catalysis or inverse rotation suppression. Imposing such dependence to the coupling in the NJL model, we numerically checked this analysis qualitatively. The pseudo critical temperature is shown to rise with the rotation and approach saturation eventually which may be induced by the model cutoff.

   hep-phnucl-thEPJC(2022)·20 citations
7. 07*

   Femtoscopic study of coupled-channel $N\Xi$ and $\Lambda \Lambda$ interactions

   Y. Kamiya🇨🇳 · K. Sasaki🇯🇵 · T. Fukui🇯🇵 · T. Hyodo🇯🇵 · K. Morita🇯🇵 · K. Ogata🇯🇵 · A. Ohnishi🇯🇵 · T. Hatsuda🇯🇵

   The momentum correlation functions of S = -2 baryon pairs (p Xi^- and Lambda Lambda) produced in high-energy pp and pA collisions are investigated on the basis of the coupled-channel formalism. The strong interaction is described by the coupled-channel HAL QCD potential obtained by the lattice QCD simulations near physical quark masses, while the hadronic source function is taken to be a static Gaussian form. The coupled-channel effect, the threshold difference, the realistic strong interaction, and the Coulomb interaction are fully taken into account for the first time in the femtoscopic analysis of baryon-baryon correlations. The characteristic features of the experimental data for the p Xi^- and Lambda Lambda pairs at LHC are reproduced quantitatively with a suitable choice of non-femtoscopic parameters and the source size. The agreement between theory and experiment indicates that the N Xi (Lambda Lambda) interaction is moderately (weakly) attractive without having a quasi-bound (bound) state.

   hep-phnucl-thPRC(2022)·68 citations
8. 08*

   Radiation Reaction Enhancement in Flying Focus Pulses

   Martin Formanek🇺🇸 · Dillon Ramsey🇺🇸 · John P. Palastro🇺🇸 · Antonino Di Piazza🇩🇪

   Radiation reaction (RR) is the oldest still-unsolved problem in electrodynamics. In addition to conceptual difficulties in its theoretical formulation, the requirement of exceedingly large charge accelerations has thus far prevented its unambiguous experimental identification. Here, we show how measurable RR effects in a laser-electron interaction can be achieved through the use of flying focus pulses (FFPs). By allowing the focus to counterpropagate with respect to the pulse phase velocity, a FFP overcomes the intrinsic limitation of a conventional laser Gaussian pulse (GP) that limits its focus to a Rayleigh range. For an electron initially also counterpropagating with respect to the pulse phase velocity, an extended interaction length with the laser peak intensity is achieved in a FFP. As a result, the same RR deceleration factors are obtained, but at FFP laser powers orders of magnitude lower than for ultrashort GPs with the same energy. This renders the proposed setup much more stable than those using GPs and allows for more accurate \emph{in situ} diagnostics. Using the Landau-Lifshitz equation of motion, we show numerically and analytically that the capability of emerging laser systems to deliver focused FFPs will allow for a clear experimental identification of RR.

   hep-phphysics.plasm-phPRA(2022)·19 citations
9. 09*

   $SO(10)$ models with $A_4$ modular symmetry

   Gui-Jun Ding🇨🇳 · Stephen F. King🇬🇧 · Jun-Nan Lu🇨🇳

   We combine $SO(10)$ Grand Unified Theories (GUTs) with $A_4$ modular symmetry and present a comprehensive analysis of the resulting quark and lepton mass matrices for all the simplest cases. We focus on the case where the three fermion families in the 16 dimensional spinor representation form a triplet of ${\Gamma }_3\simeq A_4$, with a Higgs sector comprising a single Higgs multiplet $H$ in the $10$ fundamental representation and one Higgs field $\overline{\Delta }$ in the $\overline{126}$ for the minimal models, plus and one Higgs field $\Sigma$ in the $120$ for the non-minimal models, all with specified modular weights. The neutrino masses are generated by the type-I and/or type II seesaw mechanisms and results are presented for each model following an intensive numerical analysis where we have optimized the free parameters of the models in order to match the experimental data. For the phenomenologically successful models, we present the best fit results in numerical tabular form as well as showing the most interesting graphical correlations between parameters, including leptonic CP phases and neutrinoless double beta decay, which have yet to be measured, leading to definite predictions for each of the models.

   hep-phJHEP(2021)·55 citations
10. 10*

    Structure Functions and Parton Densities: a Session Summary

    Benjamin Nachman🇺🇸 · Katarzyna Wichmann🇩🇪 · Pia Zurita🇩🇪

    Studies of fragmentation and parton density functions are a core component of researchin high energy particle and nuclear physics. These quantities are inherently interestingas a probe of the quantum nature of the strong force and are also essential ingredients toadditional studies in high energy scattering experiments. These proceedings provide anoverview of the state of the art in this area, as presented at the Deep-Inelastic ScatteringConference in the Spring of 2021.

    hep-phhep-exSciPost Phys.Proc.(2022)·1 citation
11. 11*

    $t$-channel Higgs production and constraints on off-shell Higgs couplings

    Li-Gang Xia🇨🇳

    This note is to record an unsucessful idea. I tried hard to persuade myself to write this note as I have spent a significant fraction of time during this summer. For Higgs resonant production and decaying in the $s$ channel, $i\to H\to f$, the cross section is proportional to $y_i^2{y}_f^2/{\Gamma }_H$. Thus there is a multi-solution ambiguity on the couplings due to uncertain knowledge on Higgs width. In this work, we study the process $g+q\to g+q+l^{+}+l^{-}$ with the $t$-channel Higgs boson contribution included. As Higgs boson is not on-shell, this process can be used to measure the Higgs couplings without the ambiguity. Based on the performance of the ATLAS detector in Run~II, the coupling product $y_g{y}_Z$ can be potentially constrained to be less than 18 times the Standard-Model value for a $p$-$p$ dataset of 140~fb${}^{-1}$ at $\sqrt{s}=13$~TeV. Assuming the equality of on-shell couplings and off-shell couplings and combining the on-shell measurements, the width of the Higgs boson is constrained to be less than 1.3~GeV, which is similar to that in the direct measurement. In addition, the interference effect is also analyzed.

    hep-phhep-ex0 citations
12. 12*

    Collective fast neutrino flavor conversions in a 1D box: Initial condition and long-term evolution

    Meng-Ru Wu🇹🇼 · Manu George🇹🇼 · Chun-Yu Lin🇹🇼 · Zewei Xiong🇩🇪

    We perform numerical simulations of fast collective neutrino flavor conversions in an one-dimensional box mimicking a system with the periodic boundary condition in one spatial direction and translation symmetry in the other two dimensions. We evolve the system over several thousands of the characteristic timescale (inverse of the interaction strength) with different initial ${\bar{\nu }}_e$ to ${\nu }_e$ number density ratios and different initial seed perturbations. We find that small scale structures are formed due to the interaction of the flavor waves. This results in nearly flavor depolarization in a certain neutrino phase space, when averaged over the entire box. Specifically, systems with initially equal number of ${\nu }_e$ and ${\bar{\nu }}_e$ can reach full flavor depolarization for the entire neutrino electron lepton number ($\nu$ELN) angular spectra. For systems with initially unequal ${\nu }_e$ and ${\bar{\nu }}_e$, flavor depolarization can only be reached in one side of the $\nu$ELN spectra, dictated by the net neutrino $e-x$ lepton number conservation. Quantitatively small differences depending on the initial perturbations are also found when different perturbation seeds are applied. Our numerical study here provides new insights for efforts aiming to include impact of fast flavor conversions in astrophysical simulations while calls for better analytical understanding accounting for the evolution of fast flavor conversions.

    hep-phastro-ph.HEPRD(2021)·93 citations
13. 13*

    Electromagnetic Field Produced in High Energy Small Collision System within Charge Density Models of Nucleon

    Zong-Wei Zhang🇨🇳 · Xian-Zhuo Cen🇨🇳 · Wei-Tian Deng🇨🇳

    Recent experiments show that $\Delta \gamma$, an observable designed for detecting the chiral magnetic effect (CME), in small collision system $p+A$ is similar with that in heavy ion collision $A+A$. This brings a challenge to the existence of CME because it is believed that there is no azimuthal correlation between the orientation of the magnetic field (${\Phi }_B$) and the participant plane (${\Phi }_2$) in small collision system. In this work, we introduce three charge density models to describe the inner charge distributions of proton and neutron, and calculate the electric and magnetic fields produced in small $p+A$ collisions at both RHIC and LHC energies. Our results show that the contribution of the single projectile proton to the magnetic field is the main source after average over all participants. The azimuthal correlation between ${\Phi }_B$ and ${\Phi }_2$ is small but not vanished. And due to the huge fluctuation of fields strength, the magnetic-field contribution to $\Delta \gamma$ could be large.

    hep-phnucl-thCPC(2022)·5 citations
14. 14*

    Investigating new type of doubly-charmed molecular tetraquarks composed of the charmed meson in $H$-doublet and the charmed meson in $T$-doublet

    Fu-Lai Wang🇨🇳 · Xiang Liu🇨🇳

    Stimulated by the newly reported doubly-charmed tetraquark state $T_{cc}^{+}$ by LHCb, we carry out a systematic investigation of the $S$-wave interactions between the charmed meson ($D,D^{\ast }$) in $H$-doublet and the charmed meson ($D_1,D_2^{\ast }$) in $T$-doublet by adopting the one-boson-exchange model. Both the $S$-$D$ wave mixing effect and the coupled channel effect are taken into account. By performing a quantitative calculation, we suggest that the $S$-wave $D^{\ast }{D}_1$ states with $I(J^P)=0(0^{-},1^{-})$ and the $S$-wave $D^{\ast }{D}_2^{\ast }$ state with $I(J^P)=0(1^{-})$ should be viewed as the most promising candidates of the doubly-charmed molecular tetraquark states, and the $S$-wave $D{D}_1$ state with $I(J^P)=0(1^{-})$, the $S$-wave $D{D}_2^{\ast }$ state with $I(J^P)=0(2^{-})$, and the $S$-wave $D^{\ast }{D}_2^{\ast }$ state with $I(J^P)=0(2^{-})$ are the possible doubly-charmed molecular tetraquark candidates. With the accumulation of experimental data at Run III and after High-Luminosity-LHC upgrade, these predicted doubly-charmed molecular tetraquark states can be accessible at LHCb in the near future.

    hep-phhep-exhep-latPRD(2021)·33 citations
15. 15*

    Modular $A_4$ symmetry and light dark matter with gauged $U(1{)}_{B-L}$

    Keiko I. Nagao🇯🇵 · Hiroshi Okada🇰🇷

    We propose a radiative seesaw model with a light dark matter candidate (DM) under modular $A_4$ and gauged $U(1{)}_{B-L}$ symmetries, in which neutrino masses are generated via one-loop level, and we have a bosonic DM candidate $\sim 0.01-50$ GeV. DM is stabilized by nonzero modular weight and a remnant $Z_2$ symmetry of $U(1{)}_{B-L}$ symmetry. The naturalness of tiny DM mass is indirectly realized by the radiatively induced mass of neutral fermions that interact with our DM candidate. Thus, DM mass does not have to exceed the neutral fermion masses, whose scale is assumed to be 50 GeV. Taking several benchmark points of DM mass in DM analysis, we show the numerical analysis for the neutrino oscillation data in the normal and inverted hierarchy cases and find several features for both cases.

    hep-phPhys.Dark Univ.(2022)·23 citations
16. 16*

    Tagging the initial-state gluon

    Simone Caletti🇮🇹 · Oleh Fedkevych🇮🇹 · Simone Marzani🇮🇹 · Daniel Reichelt🇩🇪

    We study the production of an electroweak boson in association with jets, in processes where the jet with the highest transverse momentum is identified as quark-initiated. The quark/gluon tagging procedure is realised by a cut on a jet angularity and it is therefore theoretically well-defined and exhibits infrared and collinear safety. In this context, exploiting resummed perturbation theory, we are able to provide theoretical predictions for transverse momentum distributions at a well-defined and, in principle, systematically improvable accuracy. In particular, tagging the leading jet as quark-initiated allows us to enhance the initial-state gluon contribution. Thus, these novel transverse momentum distributions are potentially interesting observables to probe the gluonic degrees of freedom of the colliding protons.

    hep-phhep-exEPJC(2021)·25 citations
17. 17*

    Contribution of the thermal mass to the chiral vortical effect and magnetobaryogenesis

    S. Abbaslu🇮🇷 · S. Rostam Zadeh🇮🇷 · S. S. Gousheh🇮🇷

    We show that the chiral vortical effect can exist in a nonchiral electroweak plasma in thermal equilibrium using the effective thermal masses of the fermions in the symmetric phase. We use a nonperturbative formula for the vortical current, which has been recently obtained and is a functional of the dispersion relation. Then, taking into account the effect of fermion thermal mass in the dispersion relation, we show that the corresponding hyperelectric vortical current receives implicit thermal corrections proportional to T2, from both the gauge and Yukawa interactions of the fermion. We show that the contributions of gauge interactions to the thermal masses in the total hyperelectric vortical current cancel out due to the gauge symmetries, while those of the Yukawa interactions do not cancel out. We finally show that, due to this current, only small transient vorticity fluctuations about the zero background value in a nonchiral electroweak plasma in thermal equilibrium can activate the chiral vortical effect, leading to the generation of hypermagnetic fields and matter-antimatter asymmetries in the symmetric phase of the early Universe, in the temperature range 100GeV<T<10TeV, all starting from zero initial values, even in the presence of the weak sphaleron processes.

    hep-ph1 citation
18. 18*

    Chiral soliton lattice phase in warm QCD

    Tomáš Brauner🇳🇴 · Helena Kolešová🇳🇴 · Naoki Yamamoto🇯🇵

    We analyze the phase diagram of quantum chromodynamics at low-to-moderate temperature, baryon chemical potential and external magnetic field within chiral perturbation theory at next-to-leading order of the derivative expansion. Our main result is that the anomaly-induced chiral soliton lattice (CSL) phase is stabilized by thermal fluctuations. As a consequence, the CSL state may survive up to temperatures at which chiral symmetry is restored.

    hep-phhep-thPLB(2021)·32 citations
19. 19*

    Universal Scalar Leptoquark Action for Matching

    Athanasios Dedes🇬🇷 · Kostas Mantzaropoulos🇬🇷

    In this study we present a universal effective action for one-loop matching of all scalar leptoquarks. We use both the Universal One-Loop Effective Action (UOLEA) and covariant diagrams to evaluate the Wilson coefficients directly in the Green basis for up-to dimension-6 operators. On the technical side, we use the newly developed method of evaluating supertraces, to further validate the results stemming from the use of covariant diagrams. As an application, we perform a fully functional matching onto Standard Model Effective Field Theory (SMEFT) of a model with two scalar leptoquark fields: a weak isospin singlet and a doublet. We demonstrate its use by calculating several observables, such as lepton magnetic and electric dipole moments, neutrino masses, proton decay rate, while we comment upon fine tuning issues in this model. Apart from its phenomenological interest, this model generates the majority of dimension-6 operators and provides an EFT benchmark towards future matching automation.

    hep-phJHEP(2021)·31 citations
20. 20*

    Loop-corrected Higgs Masses in the NMSSM with Inverse Seesaw Mechanism

    Thi Nhung Dao🇻🇳 · Margarete Mühlleitner🇩🇪 · Anh Vu Phan🇻🇳

    In this study, we work in the framework of the Next-to-Minimal extension of the Standard Model (NMSSM) extended by six singlet leptonic superfields. Through the mixing with the three doublet leptonic superfields, the non-zero tiny neutrino masses can be generated through the inverse seesaw mechanism. While $R$-parity is conserved in this model lepton number is explicitly violated. We quantify the impact of the extended neutrino sector on the NMSSM Higgs sector by computing the complete one-loop corrections with full momentum dependence to the Higgs boson masses in a mixed on-shell-$\overline{\text{mbox}DR}$ renormalization scheme, with and without the inclusion of CP violation. The results are consistently combined with the dominant two-loop corrections at $\mathcal{O}({\alpha }_t({\alpha }_s+{\alpha }_t))$ to improve the predictions for the Higgs mixing and the loop-corrected masses. In our numerical study we include the constraints from the Higgs data, the neutrino oscillation data, the charged lepton flavor-violating decays $l_i\to l_j+\gamma$, and the new physics constraints from the oblique parameters $S,T,U$. We present in this context the one-loop decay width for $l_i\to l_j+\gamma$. The loop-corrected Higgs boson masses are included in the Fortran code NMSSMCALC-nuSS.

    hep-phEPJC(2022)·7 citations
21. 21*

    Combined analysis of $B_c\to D_s^{(\ast )}{\mu }^{+}{\mu }^{-}$ and $B_c\to D_s^{(\ast )}\nu \bar{\nu }$ decays within $Z^{\prime }$ and leptoquark new physics models

    Manas K. Mohapatra🇮🇳 · N Rajeev🇮🇳 · Rupak Dutta🇮🇳

    We investigate the exclusive rare semileptonic decays $B_c\to D_s^{(\ast )}(\ell \ell ,\nu \bar{\nu })$ induced by neutral current transition $b\to s(\ell \ell ,\nu \bar{\nu })$ in the presence of non-universal $Z^{\prime }$, scalar and vector leptoquark new physics models. We constrain the new physics parameter space by using the latest experimental measurements of $R_{K^{(\ast )}}$, $P_5^{\prime }$, $\mathcal{B}(B_s\to \varphi {\mu }^{+}{\mu }^{-})$ and $\mathcal{B}(B_s\to {\mu }^{+}{\mu }^{-})$. Throughout the analysis, we choose to work with the particular new physics scenario $C_9^{\mu \mu }(NP)=-C_{10}^{\mu \mu }(NP)$ where both $Z^{\prime }$, $S_{1/3}^3$ and $U_{-2/3}^3$ leptoquarks satisfy the condition. Using these new coupling parameters we scrutinize the several physical observables such as differential branching fraction, the forward backward asymmetry, the lepton polarization asymmetry, the angular observable $P_5^{\prime }$ and the lepton flavor universal sensitive observables including the ratio of branching ratio $R_{D_s^{(\ast )}}$ and the few $Q$ parameters in the $B_c\to D_s^{(\ast )}{\mu }^{+}{\mu }^{-}$ and $B_c\to D_s^{(\ast )}\nu \bar{\nu }$ decay processes.

    hep-phPRD(2022)·25 citations
22. 22*

    Lepton collisions in MadGraph5_aMC@NLO

    Stefano Frixione🇮🇹 · Olivier Mattelaer🇧🇪 · Marco Zaro🇮🇹 · Xiaoran Zhao🇮🇹

    MadGraph5_aMC@NLO is a software package that allows one to simulate processes of arbitrary complexity, at both the leading and the next-to-leading order perturbative accuracy, with or without matching and multi-jet merging to parton showers. It has been designed for, and so far primarily employed in the context of, hadronic collisions. In this note, we document the implementation of a few technical features that are necessary to extend its scope to realistic ee collider environments. We limit ourselves to discussing the unpolarized beam case, but we point out that the treatment of polarized beams is conceptually identical, and that the structure we set up can easily be extended to carry out simulations at muon colliders.

    hep-ph51 citations
23. 23*

    A novel determination of the $B_c$ lifetime

    Jason Aebischer🇺🇸 · Benjamín Grinstein🇺🇸

    To reduce the current theory uncertainties a novel way to determine the $B_c$ lifetime, ${\tau }_{B_c}$, is proposed. Taking the difference of the $B_c$, and $B$ and $D$ meson decay rates eliminates the leading contributions from the calculation, which exhibit large scale and scheme dependence. The uncertainties in the proposed determination of ${\tau }_{B_c}$ are analyzed and improvements are proposed. The method predicts a value of ${\tau }_{B_c}$ in tension with the experimental determination. Several explanations are considered, including underestimation of uncertainties, duality violation and new physics. We discuss quantitative evidence that our method is vitiated by duality violation in the large mass OPE used to calculate nonleptonic decay rates of $B$ and $D$ mesons.

    hep-phhep-exhep-latPLB(2022)·19 citations
24. 24*

    Dark atoms and composite dark matter

    James M. Cline🇨🇦

    I selectively review the theoretical properties and observational limits pertaining to dark atoms, as well as composite dark matter candidates bound by a confining gauge interaction: dark glueballs, glueballinos, mesons and baryons. Emphasis is given to cosmological, direct and indirect detection constraints.

    hep-phastro-ph.COSciPost Phys.Lect.Notes(2022)·68 citations
25. 25*

    An appropriate statistical approach for nonequilibrium particle production

    Abdel Nasser Tawfik (FUE, Cairo and Egyptian Ctr. Theor. Phys., Cairo and WLCAPP, Cairo)🇪🇬 · Eman R. Abou Elyazeed🇪🇬 · A. A. Alshehri (Hafr Al Batin)🇸🇦 · Hayam Yassin (Ain Shams U., Cairo and WLCAPP, Cairo)🇪🇬

    The incapability of thermal models to accurately reproduce the horn-like structure of the Kaon-to-pion ratio measured at AGS, SPS, and low RHIC energies, as well as confirmed in the beam energy scan program, has long been a persistent problem. This issue is believed to have arisen due to the inappropriate application of statistics, particularly the extensive additive Boltzmann-Gibbs (BG) statistics. The assumption that the analysis of particle production, a dynamic nonequilibrium process, should be primarily conducted using extensive BG or nonextensive Tsallis statistics, has proven to be an unsuccessful approach that has been followed for several decades. By employing generic (non)extensive statistics, two equivalence classes $(c,d)$ emerge, thereby undermining the validity of any ad hoc assumption. Consequently, the degree of (non)extensivity exhibited by the statistical ensemble is determined by its own characteristics. This encompasses both extensive BG statistics, characterized by $(1,1)$, and nonextensive Tsallis statistics, characterized by $(0,q)$. The energy dependence of light-, ${\gamma }_q$, and strange-quark occupation factor, ${\gamma }_s$, suggests that the produced particles are most appropriately described as a nonequilibrium ensemble. This is evidenced by a remarkable nonmonotonic behavior observed in the ${\mathrm{K}}^{+}/{\pi }^{+}$ horn, for instance. On the other hand, the resulting equivalence classes $(c,d)$ are associated with a generic nonextensivity related to extended exponential and Lambert-$W_0$ exponentially generating distribution function, which evidently arise from free, short- and long-range correlations. The incorporation of generic nonextensive statistics into the hadron resonance gas model yields an impressive ability to rightfully reproduce the nonmonotonic ${\mathrm{K}}^{+}/{\pi }^{+}$ ratio.

    hep-phMod.Phys.Lett.B(2025)·2 citations
26. 26*

    Revealing the Primordial Irreducible Inflationary Gravitational-Wave Background with a Spinning Peccei-Quinn Axion

    Yann Gouttenoire🇮🇱 · Géraldine Servant🇩🇪 · Peera Simakachorn🇩🇪

    The primordial irreducible gravitational-wave background due to quantum vacuum tensor fluctuations produced during inflation spans a large range of frequencies with an almost scale-invariant spectrum but is too low to be detected by the next generation of gravitational-wave interferometers. We show how this signal is enhanced by a short temporary kination era in the cosmological history (less than 10 e-folds), that can arise at any energy scale between a GeV and the inflationary scale $10^{16}$ GeV. We argue that such kination era is naturally generated by a spinning axion before it gets trapped by its potential. It is usually assumed that the axion starts oscillating around its minimum from its initially frozen position. However, the early dynamics of the Peccei-Quinn field can induce a large kinetic energy in the axion field, triggering a kination era, either before or after the axion acquires its mass, leading to a characteristic peak in the primordial gravitational-wave background. This represents a smoking-gun signature of axion physics as no other scalar field dynamics is expected to trigger such a sequence of equations of state in the early universe. We derive the resulting gravitational-wave spectrum, and present the parameter space that leads to such a signal as well as the detectability prospects, in particular at LISA, Einstein Telescope, Cosmic Explorer and Big Bang Observer. We show both model-independent predictions and present as well results for two specific well-motivated UV completions for the QCD axion dark matter where this dynamics is built-in.

    hep-phastro-ph.CO69 citations
27. 27*

    Heavy QCD Axion at Belle II: Displaced and Prompt Signals

    Emilie Bertholet🇮🇱 · Sabyasachi Chakraborty🇺🇸 · Vazha Loladze🇺🇸 · Takemichi Okui🇺🇸 · Abner Soffer🇮🇱 · Kohsaku Tobioka🇺🇸

    The QCD axion is a well-motivated addition to the standard model to solve the strong $CP$ problem. If the axion acquires mass dominantly from a hidden sector, it can be as heavy as $O(1)$ GeV, and the decay constant can be as low as $O(100)$ GeV without running into the axion quality problem. We propose new search strategies for such heavy QCD axions at the Belle II experiment, where the axions are expected to be produced via $B\to Ka$. We find that a subsequent decay $a\to 3\pi$ with a displaced vertex leads to a unique signal with essentially no background, and that a dedicated search can explore the range $O(1$-$10)$ TeV of decay-constant values. We also show that $a\to \gamma \gamma$ can cover a significant portion of currently unexplored region of $150\lesssim m_a\lesssim 500$ MeV.

    hep-phhep-exPRD(2022)·58 citations
28. 28*

    Solar Reflection of Dark Matter

    Haipeng An🇨🇳 · Haoming Nie🇨🇳 · Maxim Pospelov🇺🇸 · Josef Pradler🇦🇹 · Adam Ritz🇨🇦

    The scattering of light dark matter off thermal electrons inside the Sun produces a "fast" sub-component of the dark matter flux that may be detectable in underground experiments. We update and extend previous work by analyzing the signatures of dark matter candidates which scatter via light mediators. Using numerical simulations of the dark matter-electron interaction in the solar interior, we determine the energy spectrum of the reflected flux, and calculate the expected rates for direct detection experiments. We find that large Xenon-based experiments (such as XENON1T) provide the strongest direct limits for dark matter masses below a few MeV, reaching a sensitivity to the effective dark matter charge of better than $\sim 10^{-9}e$.

    hep-phastro-ph.SRhep-exPRD(2021)·87 citations
29. 29*

    Gravitational Waves from the Cosmological Quark-Hadron Phase Transition Revisited

    Pauline Lerambert-Potin🇫🇷 · Jose Antonio de Freitas Pacheco🇫🇷

    The recent claim by the NANOGrav collaboration of a possible detection of an isotropic gravitational wave background stimulated a series of investigations searching for the origin of such a signal. The QCD phase transition appears as a natural candidate and in this paper the gravitational spectrum generated during the conversion of quarks into hadrons is calculated. Here, contrary to recent studies, equations of state for the quark-gluon plasma issued from the lattice approach were adopted. The duration of the transition, an important parameter affecting the amplitude of the gravitational wave spectrum, was estimated self-consistently with the dynamics of the universe controlled by the Einstein equations. The gravitational signal generated during the transition peaks around 0,28 \mu Hz, being unable to explain the claimed NANOGrav signal. However, the expected QCD gravitational wave background could be detected by the planned spatial interferometer Big Bang Observer in its advanced version for frequencies above 1.0 mHz. This possible detection assumes that algorithms recently proposed will be able to disentangle the cosmological signal from that expected for the astrophysical background generated by black hole binaries.

    hep-phastro-ph.COgr-qcUniverse(2021)·9 citations
30. 30*

    The Physics of Neutrinoless Double Beta Decay: A Primer

    B.J.P. Jones🇺🇸

    Neutrinoless double beta decay is a hypothetical radioactive process which, if observed, would prove the neutrino to be a Majorana fermion: a particle that is its own antiparticle. In this lecture mini-series I discuss the physics of Majorana fermions and the connection between the nature of neutrino mass and neutrinoless double beta decay. We review Dirac and Majorana spinors, discuss methods of distinguishing between Majorana and Dirac fermions, and derive in outline the connection between neutrino mass and double beta decay rates. We conclude by briefly summarizing the experimental landscape and the challenges associated with searches for this elusive process.

    ↳ nucl-exhep-phnucl-th35 citations
31. 31*

    First direct detection constraints on Planck-scale mass dark matter with multiple-scatter signatures using the DEAP-3600 detector

    P. Adhikari🇨🇦 · R. Ajaj🇨🇦 · M. Alpízar-Venegas🇲🇽 · D. J. Auty🇨🇦 · H. Benmansour🇨🇦 · C. E. Bina🇨🇦 · W. Bonivento🇮🇹 · M. G. Boulay🇨🇦 · M. Cadeddu🇮🇹 · B. Cai🇨🇦 · M. Cárdenas-Montes🇪🇸 · S. Cavuoti🇮🇹 and 85 other authors

    Dark matter particles with Planck-scale mass ($\simeq 10^{19}\text{GeV}/c^2$) arise in well-motivated theories and could be produced by several cosmological mechanisms. Using a blind analysis of data collected over a 813 d live time with DEAP-3600, a 3.3 t single-phase liquid argon-based dark matter experiment at SNOLAB, a search for supermassive dark matter was performed, looking for multiple-scatter signals. No candidate signal events were observed, leading to the first direct detection constraints on Planck-scale mass dark matter. Leading limits constrain dark matter masses between $8.3\times 10^6$ and $1.2\times 10^{19}\text{GeV}/c^2$, and cross sections for scattering on ${}^{40}$Ar between $1.0\times 10^{-23}$ and $2.4\times 10^{-18}{\text{cm}}^2$. These are used to constrain two composite dark matter models.

    ↳ astro-ph.COastro-ph.HEhep-exhep-phPRL(2022)·83 citations
32. 32*

    Mellin-Barnes and the method of brackets

    Ivan Gonzalez · Igor Kondrashuk🇨🇱 · Victor H. Moll · Luis M. Recabarren

    The method of brackets is a method for the evaluation of definite integrals based on a small number of rules. This is employed here for the evaluation of Mellin-Barnes integral. The fundamental idea is to transform these integral representations into a bracket series to obtain their values. The expansion of the gamma function in such a series constitute the main part of this new application. The power and flexibility of this procedure is illustrated with a variety of examples.

    ↳ math.CVhep-phmath-phmath.MP+1EPJC(2022)·9 citations
33. 33*

    Polarizabilities of microparticles in relativistic field theory

    N.V. Maksimenko🇧🇾 · O.M. Deruzhkova🇧🇾 · S.A. Lukashevich🇧🇾

    The article determine a relativistic tensor of the second rank containing the vectors of the electric and magnetic polarization of the medium, based on the Maxwell equations and the determination of the charge density and polarization current of a structural microparticle. Using this tensor and the electromagnetic field tensor, the relativistic lagrangian of the interaction an electromagnetic field with a structural microparticle is obtained, taking into account the polarization of its structural elements. Based on the induced moments, the relativistic lagrangian of the interaction an electromagnetic field with a structural microparticle is constructed with considering the electric and magnetic polarizabilities.

    ↳ physics.class-phhep-phRuss.Phys.J.(2022)·0 citations
34. 34*

    Evidence of the triaxial structure of ${}^{129}$Xe at the Large Hadron Collider

    Benjamin Bally🇪🇸 · Michael Bender🇫🇷 · Giuliano Giacalone🇩🇪 · Vittorio Somà🇫🇷

    The interpretation of the emergent collective behaviour of atomic nuclei in terms of deformed intrinsic shapes [1] is at the heart of our understanding of the rich phenomenology of their structure, ranging from nuclear energy to astrophysical applications across a vast spectrum of energy scales. A new window onto the deformation of nuclei has been recently opened with the realization that nuclear collision experiments performed at high-energy colliders, such as the CERN Large Hadron Collider (LHC), enable experimenters to identify the relative orientation of the colliding ions in a way that magnifies the manifestations of their intrinsic deformation [2]. Here we apply this technique to LHC data on collisions of ${}^{129}$Xe nuclei [3-5] to exhibit the first evidence of non-axiality in the ground state of ions collided at high energy. We predict that the low-energy structure of ${}^{129}$Xe is triaxial (a spheroid with three unequal axes), and show that such deformation can be determined from high-energy data. This result demonstrates the unique capabilities of precision collider machines such as the LHC as new means to perform imaging of the collective structure of atomic nuclei.

    ↳ nucl-thhep-exhep-phnucl-exPRL(2022)·105 citations
35. 35*

    High energy beam energy measurement with microwave-electron Compton backscattering

    Meiyu Si🇨🇳 · Yongsheng Huang🇨🇳 · Shanhong Chen🇨🇳 · Pengcheng Wang🇨🇳 · Zhe Duan🇨🇳 · Xiaofei Lan🇨🇳 · Yuan Chen🇨🇳 · Xinchou Lou🇨🇳 · Manqi Ruan🇨🇳 · Yiwei Wang🇨🇳 · Guangyi Tang🇨🇳 · Ouzheng Xiao🇨🇳 · Jianyong Zhang🇨🇳

    The uncertainty of the energy measurement of the electron beam on circular electron positron collider (CEPC) must be smaller than 10$\mathrm{MeV}$ to make sure the accurate measurement of the mass of the Higgs boson. In order to simplify the energy measurement system, a new method is proposed by fitting the Compton edge of the energy distribution of the gamma ray from a microwave-electron Compton scattering. With our method, the uncertainty of the energy measurement is 6$\mathrm{MeV}$ for the electron energy of $120\mathrm{GeV}$ in the Higgs mode. In this system, the energy resolution of the gamma detection needs to reach $10^{-4}$. Therefore, only the high-purity germanium (HPGe) detector can meet the critical requirement. In a head-on collision mode, the initial photons should be microwave photons with the wavelength of 3.04 centimeters. A cylindrical resonant cavity with selected $T{M}_{010}$ mode is used to transmit microwaves. After the microwave-electron Compton backscattering, the scattered photons and the synchrotron-radiation background transmit a shielding structure and then are detected by a HPGe detector at the end of the beam line of the synchrotron-radiation applications. The hole radius in the side wall of the cavity is about $1.5\mathrm{mm}$ to allow the electron beam passing through. The results of the computer simulation technology (CST) software shows that the influence of the hole radius on the cavity field is negligible. The change of the resonance frequency can be easily corrected by fine-tuning the cavity size.

    ↳ hep-exhep-phNucl.Instrum.Meth.A(2022)·3 citations
36. 36*

    Schwinger-Keldysh effective action for relativistic Brownian particle in AdS-CFT

    Yanyan Bu🇨🇳 · Biye Zhang🇨🇳

    We compute Schwinger-Keldysh effective action for a relativistic heavy quark (with constant background velocity) in strongly coupled N = 4 supersymmetric Yang-Mills plasma. The holographic dual description involves a noisy trailing string moving in Schwarzschild-AdS5 black brane. The noise is caused by Hawking radiation emitted from string worldsheet horizon. Besides quadractic terms, the effective action contains cubic interactions, which are entirely induced by the constant background velocity. The nonlinear fluctuation-dissipation relations for three-point functions are discussed based on holographic results.

    ↳ hep-thhep-phPRD(2021)·21 citations
37. 37*

    Numerical fluid dynamics for FRG flow equations: Zero-dimensional QFTs as numerical test cases. II. Entropy production and irreversibility of RG flows

    Adrian Koenigstein🇩🇪 · Martin J. Steil🇩🇪 · Nicolas Wink🇩🇪 · Eduardo Grossi🇺🇸 · Jens Braun🇩🇪

    We demonstrate that the reformulation of renormalization group (RG) flow equations as non-linear heat equations has severe implications on the understanding of RG flows in general. We demonstrate by explicitly constructing an entropy function for a zero-dimensional ${\mathbb{Z}}_2$-symmetric model that the dissipative character of generic non-linear diffusion equations is also hard-coded in the functional RG equation. This renders RG flows manifestly irreversible, revealing the semi-group property of RG transformations on the level of the flow equation itself. Additionally, we argue that the dissipative character of RG flows, its irreversibility and the entropy production during the RG flow may be linked to the existence of a so-called $\mathcal{C}$-/$\mathcal{A}$-function. In total, this introduces an asymmetry in the so-called RG time -- in complete analogy to the thermodynamic arrow of time -- and allows for an interpretation of infrared actions as equilibrium solutions of dissipative RG flows equations. The impossibility of resolving microphysics from macrophysics is evident in this framework. Furthermore, we directly link the irreversibility and the entropy production in RG flows to an explicit numerical entropy production, which is manifest in diffusive and non-linear partial differential equations (PDEs) and a standard mathematical tool for the analysis of PDEs. Using exactly solvable zero-dimensional ${\mathbb{Z}}_2$-symmetric models, we explicitly compute the (numerical) entropy production related to the total variation non-increasing property of the PDE during RG flows toward the infrared limit. Finally, we discuss generalizations of our findings and relations to the $\mathcal{C}$-/$\mathcal{A}$-theorem as well as how our work may help to construct truncations of RG flow equations in the future, including numerically stable schemes for solving the corresponding PDEs.

    ↳ cond-mat.stat-mechhep-phhep-thphysics.flu-dynPRD(2022)·50 citations
38. 38*

    Primordial Standard Clock Models and CMB Residual Anomalies

    Matteo Braglia🇪🇸 · Xingang Chen🇺🇸 · Dhiraj Kumar Hazra🇮🇳

    The residuals of the power spectra of WMAP and Planck's cosmic microwave background (CMB) anisotropies data are known to exhibit a few interesting anomalies at different scales with marginal statistical significance. Combining bottom-up and top-down model-building approaches and using a pipeline that efficiently compares model predictions with data, we construct a model of primordial standard clock that is able to link and address the anomalies at both the large and small scales. This model, and its variant, provide some of the best fits to the feature anomalies in CMB. According to Bayes evidences, these models are currently statistically indistinguishable from the Standard Model. We show that the difference between them will soon become statistically significant with various higher quality data on the CMB polarization. We demonstrate that such a model-building and data-analyses process may be used to uncover a portion of detailed evolutionary history of our universe during its primordial epoch.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2022)·39 citations
39. 39*

    Pileup Correction on Higher-order Cumulants with Unfolding Approach

    Yu Zhang🇨🇳 · Yige Huang🇨🇳 · Toshihiro Nonaka🇯🇵 · Xiaofeng Luo🇨🇳

    Higher-order cumulants of conserved charge distributions are sensitive observables to probe the critical fluctuations near QCD critical point in heavy-ion collisions. Due to high interaction rate, pileup event can be one of the major sources of background in the measurements of higher-order cumulants. In this paper, we studied the effects of pileup events on higher-order cumulants of proton multiplicity distributions using UrQMD model. It is found that the proposed pileup correction fails if the correction parameters are determined by the Glauber fitting of charged particle multiplicities, which is usually done in the real heavy-ion experiment. To address this, we propose a model independent unfolding approach to determine the parameters in the pileup correction. This approach can be applied in the pileup correction for the future measurement of higher-order cumulants in heavy-ion collision experiment.

    ↳ physics.data-anhep-exhep-phnucl-ex+1Nucl.Instrum.Meth.A(2022)·13 citations
40. 40*

    LREE of an Unstable Dressed-Dynamical D$p$-brane: Superstring Calculations

    Shirin Teymourtashlou🇮🇷 · Davoud Kamani🇮🇷

    We obtain the left-right entanglement entropy (LREE) for a D$p$-brane with tangential motion in the presence of a $U(1)$ gauge potential, the Kalb-Ramond field and an open string tachyon field. Thus, at first we extract the Rényi entropy and then by taking a special limit of it we acquire the entanglement entropy. We shall investigate the behavior of the LREE under the tachyon condensation phenomenon. We observe that the deformation of the LREE, through this process, reveals the collapse of the brane. Besides, we examine the second law of thermodynamics for the LREE under tachyon condensation, and we extract the imposed constraints. Note that our calculations will be in the context of the type IIA/IIB superstring theories.

    ↳ hep-thhep-phEPJC(2021)·14 citations
41. 41*

    Primordial Gravitational Wave Circuit Complexity

    Kiran Adhikari🇩🇪 · Sayantan Choudhury🇮🇳 · Hardey N. Pandya🇮🇳 · Rohan Srivastava🇮🇳

    In this article, we investigate various physical implications of quantum circuit complexity using squeezed state formalism of Primordial Gravitational Waves (PGW). Recently quantum information theoretic concepts, such as entanglement entropy, and complexity are playing a pivotal role to understand the dynamics of quantum system even in the diverse fields such as, high energy physics and cosmology. This paper is devoted in studying quantum circuit complexity of PGW for various cosmological models, such as de Sitter, inflation, radiation, reheating, matter, bouncing, cyclic and black hole gas model etc. We compute complexity measure using both Covariance and Nielsen's wave function method for three different choices of quantum initial vacua: Motta-Allen, $\alpha$ and Bunch-Davies. Besides computing circuit complexity, we have also computed Von-Neumann entanglement entropy. By making the comparison of complexity with entanglement entropy, we are able to probe various features regarding the dynamics of evolution for different cosmological models. Because entanglement entropy is independent of the squeezing angle, we are able to understand more details of the system using Nielsen's measure of complexity which is dependent on both squeezing parameter and angle. This implies that quantum complexity could indeed be a useful probe to study quantum features in cosmological scale. Quantum complexity is also becoming a powerful technique to understand the chaotic behaviour and random fluctuations of quantum fields. Using the growth of complexity, we are able to compute quantum Lyapunov exponent for various cosmological models and comment on it's chaotic nature.

    ↳ gr-qccond-mat.stat-mechhep-phhep-th+1Symmetry(2023)·25 citations
42. 42*

    Charmonium and bottomonium spectroscopy at Belle II

    Ashish Thampi🇩🇪

    The Belle II experiment at the SuperKEKB energy-asymmetric $e^{+}{e}^{-}$ collider is an upgrade of the B factory facility at KEK in Tsukuba, Japan. The experiment began operation in 2019 and aims to record a factor of 50 times more data than its predecessor. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now number in the dozens, and represent the emergence of a new category within quantum chromodynamics. We present recent results obtained from Belle II data, and the future prospects to explore both exotic and conventional quarkonium physics.

    ↳ hep-exhep-phSciPost Phys.Proc.(2022)·0 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.