Wed·May 31, 2023Wednesday·May 31, 2023

1. 01*

   The QCD Axion: A Unique Player in the Axiverse with Mixings

   Kai Murai🇯🇵 · Fuminobu Takahashi🇯🇵 · Wen Yin🇯🇵

   In an axiverse with numerous axions, the cosmological moduli problem poses a significant challenge because the abundance of axions can easily exceed that of dark matter. The well-established stochastic axion scenario offers a simple solution, relying on relatively low-scale inflation. However, axions are typically subject to mixing due to mass and kinetic terms, which can influence the solution using stochastic dynamics. Focusing on the fact that the QCD axion has a temperature-dependent mass, unlike other axions, we investigate the dynamics of the QCD axion and another axion with mixing. We find that the QCD axion abundance is significantly enhanced and becomes larger than that of the other axion for a certain range of parameters. This enhancement widens the parameter regions accounting for dark matter. In addition, we also find a parameter region in which both axions have enhanced abundances of the same order, which result in multi-component dark matter.

   hep-phastro-ph.COPRD(2023)·26 citations
2. 02*

   Fate of the topological susceptibility in two-color dense QCD

   Mamiya Kawaguchi🇨🇳 · Daiki Suenaga🇯🇵

   We explore the topological susceptibility at finite quark chemical potential and zero temperature in two-color QCD (QC${}_2$D) with two flavors. Through the Ward-Takahashi identities of QC${}_2$D, we find that the topological susceptibility in the vacuum solely depends on three observables: the pion decay constant, the pion mass, and the $\eta$ mass in the low-energy regime of QC${}_2$D. Based on the identities, we numerically evaluate the topological susceptibility at finite quark chemical potential using the linear sigma model with the approximate Pauli-Gursey $SU(4)$ symmetry. Our findings indicate that, in the absence of $U(1{)}_A$ anomaly effects represented by the Kobayashi-Maskawa-'t Hooft-type determinant interaction, the topological susceptibility vanishes in both the hadronic and baryon superfluid phases. On the other hand, when the $U(1{)}_A$ anomaly effects are present, the constant and nonzero topological susceptibility is induced in the hadronic phase, reflecting the mass difference between the pion and $\eta$ meson. Meanwhile, in the superfluid phase it begins to decrease smoothly. The asymptotic behavior of the decrement is fitted by the continuous reduction of the chiral condensate in dense QC${}_2$D, which is similar to the behavior observed in hot three-color QCD matter. In addition, effects from the finite diquark source on the topological susceptibility are discussed. We expect that the present study provides a clue to shed light on the role of the $U(1{)}_A$ anomaly in cold and dense QCD matter.

   hep-phhep-latnucl-thJHEP(2023)·18 citations
3. 03*

   Constraints on the dark Z model from the Higgs boson phenomenology

   Dong-Won Jung🇰🇷 · Kang Young Lee🇰🇷 · Chaehyun Yu🇰🇷

   We study constraints on the hidden sector model mediated by an additional SU(2) Higgs doublet from the phenomenology of Higgs bosons. The hidden sector is assumed to contain a hidden U(1) gauge symmetry and the hidden U(1) gauge boson gets the mass by the electroweak symmetry breaking to be a dark Z boson. The Higgs sector of the model is similar to that of the two Higgs doublet model of type I except for the absence of the CP-odd scalar boson. Using the programs of HiggsBounds and HiggsSignals, we incorporate current experimental limits from LEP, Tevatron and LHC to examine the Higgs sector in our model and derive constraints on model parameters. We also discuss the implications of the model on the dark matter phenomenology.

   hep-phPRD(2023)·6 citations
4. 04*

   Forward-backward correlations with the $\Sigma$ quantity in the wounded constituent framework at LHC energies

   Iwona Anna Sputowska🇵🇱

   $\Sigma$ is a new correlation measure, quite recently introduced to heavy-ion physics. This measure, defined in the independent source model as a strongly intensive quantity, is expected to be free of the effects of system volume and volume fluctuations. This paper discusses the forward-backward correlation quantified with the $\Sigma$ observable calculated in the framework of the wounded nucleon model (WNM) and wounded quark model (WQM). Findings show that the wounded constituent approach outperforms the commonly used heavy-ion Monte Carlo generators, such as HIJING, AMPT or EPOS, by accurately describing the experimental data on FB correlations with $\Sigma$ measured by ALICE in Xe--Xe reactions at $\sqrt{s_{\mathrm{NN}}}$=5.44 TeV and in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$= 2.76 and 5.02 TeV. This paper demonstrates that $\Sigma$ can be a unique tool for determining the fragmentation function of a wounded constituent in a symmetric nucleus-nucleus collision. However, in the wounded constituent framework, it is no longer a strongly intensive quantity.

   hep-phhep-exnucl-exnucl-thPRC(2023)·3 citations
5. 05*

   Unified triquark equations

   A. N. Kvinikhidze🇬🇪 · B. Blankleider🇦🇺

   We derive covariant equations describing the three-quark bound state in terms of quark and diquark degrees of freedom. The equations are exact in the approximation where three-body forces are neglected. A feature of these equations is that they unify two often-used but seemingly unrelated approaches that model baryons as quark-diquark systems; namely, (i) the approach using Poincaré covariant quark+diquark Faddeev equations driven by a one-quark-exchange kernel [pioneered by Cahill {\it et al.}, Austral.\ J.\ Phys.\ {\bf 42}, 129 (1989) and Reinhardt, Phys.\ Lett.\ B {\bf 244}, 316 (1990)], and (ii) the approach using the quasipotential quark-diquark bound-state equation where the kernel consists of the lowest-order contribution from an underlying quark-quark potential [pioneered by Ebert {\it et al.}, Z.\ Phys.\ C {\bf 76} 111 (1997)]. In particular, we show that each of these approaches corresponds to the unified equations with its kernel taken in different, non-overlapping, approximations.

   hep-phnucl-thPRD(2023)·1 citation
6. 06*

   The Global Fits of New Physics in $b\to s$ after $R_{K^{(\ast )}}$ 2022 Release

   Qiaoyi Wen🇨🇳 · Fanrong Xu🇨🇳

   The measurement of lepton universality parameters $R_{K^{(\ast )}}$ was updated by LHCb in December 2022, which indicated that the well-known anomalies in flavor-changing neutral current (FCNC) processes of B meson decays have faded away. However, does this mean that all new physics possibilities related to $b\to s{\ell }^{+}{\ell }^{-}$ have been excluded? We aim to answer this question in this work. The state-of-the-art effective Hamiltonian is adopted to describe $b\to s$ transition, while BSM (beyond the Standard Model) new physics effects are encoded in Wilson coefficients (WCs). Using around 200 observables in leptonic and semileptonic decays of B mesons and bottom baryons, measured by LHCb, CMS, ATLAS, Belle, and BaBar, we perform global fits of these Wilson coefficients in four different scenarios. In particular, lepton flavors in WCs are specified in some of the working scenarios. To see the change of new physics parameters, we use both the data before and after the 2022 release of $R_{K^{(\ast )}}$ in two separate sets of fits. We find that in three of the four scenarios, $\Delta C_9^{\mu }$ still has a deviation around or more than $4\sigma$ from the Standard Model. The lepton flavor in WCs is distinguishable for $\Delta C_9$ at the $1\sigma$ level, but at the $2\sigma$ level all the operators are flavor identical. We demonstrate numerically that there is no chirality for muon type of scalar operator and it is kept at the $1\sigma$ level for their electron type dual ones, while chiral difference exists for ${\mathcal{O}}_9^{\mu }$ at least at the $2\sigma$ level. Moreover, it can be deduced that the scalar operators ${\mathcal{O}}_{S,P}^{{(}^{\prime })\mu }$ become null if new physics emerges in terms of SMEFT (Standard Model Effective Field Theory) up to dimension-6.

   hep-phPRD(2023)·34 citations
7. 07*

   Distinguishing the spins of $P_c(4440)$ and $P_c(4457)$ with femtoscopic correlation functions

   Zhi-Wei Liu🇨🇳 · Jun-Xu Lu🇨🇳 · Ming-Zhu Liu🇨🇳 · Li-Sheng Geng🇨🇳

   The spins of the pentaquark states $P_c(4440)$ and $P_c(4457)$ play a decisive role in unraveling their nature, but remain undetermined experimentally. Assuming that they are ${\Sigma }_c{\bar{D}}^{\ast }$ bound states, we demonstrate how one can determine their spins by measuring the ${\Sigma }_c^{+}{\bar{D}}^{(\ast )0}$ correlation functions. We show that one can use the ${\Sigma }_c^{+}{\bar{D}}^0$ correlation function to fix the size of the Gaussian source and then determine the strength of the ${\Sigma }_c^{+}{\bar{D}}^{\ast 0}$ interaction of spin $1/2$ and $3/2$ and therefore the spins of the $P_c(4440)$ and $P_c(4457)$ states. The method proposed can be applied to decipher the nature of other hadronic molecules and thus deepen our understanding of the nonperturbative strong interaction.

   hep-phhep-exPRD(2023)·47 citations
8. 08*

   $P_c$ states and their open-charm decays with the complex scaling method

   Zi-Yang Lin🇨🇳 · Jian-Bo Cheng🇨🇳 · Bo-Lin Huang🇨🇳 · Shi-Lin Zhu🇨🇳

   A partial width formula is proposed using the analytical extension of the wave function in momentum space. The distinction of the Riemann sheets is explained from the perspective of the Schrodinger equation. The analytical form in coordinate space and the partial width are derived subsequently. Then a coupled-channel analysis is performed to investigate the open-charm branching ratios of the $P_c$ states, involving the contact interactions and one-pion-exchange potential with the three-body effects. The low energy constants are fitted using the experimental masses and widths as input. The $P_c(4312)$ is found to decay mainly to ${\Lambda }_c{\bar{D}}^{\ast }$, while the branching ratios of the $P_c(4440)$ and $P_c(4457)$ in different channels are comparable. Under the reasonable assumption that the off-diagonal contact interactions are small, the $J^P$ quantum numbers of the $P_c(4440)$ and the $P_c(4457)$ prefer ${\frac{1}{2}}^{-}$ and ${\frac{3}{2}}^{-}$ respectively. Three additional $P_c$ states at 4380 MeV, 4504 MeV and 4516 MeV, together with their branching ratios, are predicted. A deduction of the revised one-pion-exchange potential involving the on-shell three-body intermediate states is performed.

   hep-phhep-exhep-latnucl-thPRD(2023)·21 citations
9. 09*

   Mechanical structures inside proton with configurational entropy language

   Wei Kou🇨🇳 · Xurong Chen🇨🇳

   The structure of the proton remains a significant challenge within the field of Quantum Chromodynamics, with the origin of its spin and mass still lacking a satisfactory explanation. In this study, we utilize the gravitational form factor of the proton as the foundation for constructing the configurational entropy of the proton energy system. In our approach we choose the holographic QCD model for input thus obtaining a holographic version of the proton energy density. Employing this approach, we are able to determine key mechanical quantities such as the proton's mass radius and pressure distribution. Our analysis yields the root-mean-square mass radius of $\sqrt{⟨r_M^2⟩}=0.720$ fm and scalar radius of $\sqrt{⟨r_S^2⟩}=1.024$ fm for proton, which are found to be in excellent agreement with recent measurements from the Hall-C collaboration group at Jefferson Lab. Additionally, we examine the radial distribution of pressure and shear force within the proton. We provide a new mode for constraining holographic model parameters in the investigation of proton structures.

   hep-phhep-thPLB(2023)·12 citations
10. 10*

    Potential and string breaking of doubly heavy baryon at finite temperature and chemical potential

    Bo Yu🇨🇳 · Xi Guo🇨🇳 · Xun Chen🇨🇳 · Xiao-Hua Li🇨🇳

    Using gauge/gravity duality, we first study the string breaking and melting of doubly heavy baryon at a finite chemical potential and temperature in this paper. The decay mode $\mathrm{QQq}\to \mathrm{Qqq}+\mathrm{Q}\bar{\mathrm{q}}$ is investigated with the presence of temperature and chemical potential in this paper. With the increase of temperature and chemical potential, string breaking takes place at a smaller potential energy and the string-breaking distance will increase slightly. It is also found that the $\mathrm{QQq}$ melts at small separate distance with the increase of temperature and chemical potential. Then, we compare the screening distance of $\mathrm{QQq}$ with $\mathrm{Q}\bar{\mathrm{Q}}$ under the same conditions. Finally, we draw the melting diagram of $\mathrm{QQq}$ and $\mathrm{Q}\bar{\mathrm{Q}}$ in the $T-\mu$ plane.

    hep-phPRD(2023)·4 citations
11. 11*

    Interpreting dark matter solution for $B-L$ gauge symmetry

    Phung Van Dong🇻🇳

    It is shown that the solution for $B-L$ gauge symmetry with $B-L=-4,-4,+5$ assigned for three right-handed neutrinos respectively, reveals a novel scotogenic mechanism with implied matter parity for neutrino mass generation and dark matter stability. Additionally, the world with two-component dark matter is hinted.

    hep-phhep-thPRD(2023)·9 citations
12. 12*

    Unitarity, real-intermediate states, and fixed-order approach to resonant dark matter annihilation

    Peter Maták🇸🇰

    We study the role of perturbative unitarity in the resonant annihilation of two dark matter particles into the standard model bath. Systematically including all kinematically allowed holomorphic cuts of the corresponding forward-scattering diagram, cancelation of the singularities occurs, resulting in a fixed-order correction to the narrow-width approximation for the annihilation cross section. Unlike the standard approach based on including the finite width of the mediator, no double counting of intermediate states occurs.

    hep-phPRD(2024)·5 citations
13. 13*

    Dark Photons from Charged Pion Bremsstrahlung at Proton Beam Experiments

    David Curtin🇨🇦 · Yonatan Kahn🇺🇸 · Rachel Nguyen🇺🇸

    The production and subsequent re-scattering of secondary pions produced in proton beam dumps provides additional opportunities for the production of light new particles like dark photons. This new mechanism has been overlooked in the past but can extend the mass reach of the SpinQuest experiment and its proposed DarkQuest upgrade. We use chiral perturbation theory to calculate the production of kinetically mixed dark photons through bremsstrahlung off secondary charged pions. We find that the reach of SpinQuest/DarkQuest can be pushed further into the multi-GeV mass range compared to estimates based only on primary dark photon production through meson decay or proton bremsstrahlung. Our analysis can be regarded as the first of several steps to include secondary pion contributions. In an upcoming analysis we will extend our calculation into the high-momentum-transfer regime through the use of pion PDFs and including hadronic resonances, which will further increase the estimated mass reach.

    hep-phhep-exPRD(2023)·12 citations
14. 14*

    Renormalons in the energy-energy correlator

    Stella T. Schindler🇺🇸 · Iain W. Stewart🇺🇸 · Zhiquan Sun🇺🇸

    The energy-energy correlator (EEC) is an observable of wide interest for collider physics and Standard Model measurements, due to both its simple theoretical description in terms of the energy-momentum tensor and its novel features for experimental studies. Significant progress has been made in both applications and higher-order perturbative predictions for the EEC. Here, we analyze the nature of the asymptotic perturbative series for the EEC by determining its analytic form in Borel space under the bubble-sum approximation. This result provides information on the leading and subleading nonperturbative power corrections through renormalon poles. We improve the perturbative convergence of the $\overline{\mathrm{MS}}$ series for the EEC by removing its leading renormalon using an R scheme, which is independent of the bubble-sum approximation. Using the leading R-scheme power correction determined by fits to thrust, we find good agreement with EEC OPAL data already at $\mathcal{O}({\alpha }_s^2)$.

    hep-phhep-thnucl-thJHEP(2023)·60 citations
15. 15*

    Hints of a new leptophilic Higgs sector?

    Yoav Afik🇨🇭 · P. S. Bhupal Dev🇺🇸 · Anil Thapa🇺🇸

    We show that a new leptophilic Higgs sector can resolve some intriguing anomalies in current experimental data across multiple energy ranges. Motivated by the recent CMS excess in the resonant $e\mu$ channel at 146 GeV, we focus on a leptophilic two-Higgs-doublet model, and propose a resonant production mechanism for the neutral components of the second Higgs doublet at the LHC using the lepton content of the proton. Interestingly, the same Yukawa coupling $Y_{e\mu }\sim 0.6-0.8$ that explains the CMS excess also addresses the muon $(g-2)$ anomaly. Moreover, the new Higgs doublet also resolves the recent CDF $W$-boson mass anomaly. The relevant model parameter space will be completely probed by future LHC data.

    hep-phhep-exPRD(2024)·13 citations
16. 16*

    The Two Scales of New Physics in Higgs Couplings

    Raffaele Tito D'Agnolo🇫🇷 · Florian Nortier🇫🇷 · Gabriele Rigo🇫🇷 · Pablo Sesma🇫🇷

    Higgs coupling deviations from Standard Model predictions contain information about two scales of Nature: that of new physics responsible for the deviation, and the scale where new bosons must appear. The two can coincide, but they do not have to. The scale of new bosons can be calculated by going beyond an effective field theory description of the coupling deviation. We compute model-independent upper bounds on the scale of new bosons for deviations in Higgs to $WW$ and $ZZ$ couplings, finding that any measured deviation at present or future colliders requires the existence of new bosons within experimental reach. This has potentially interesting implications for naturalness.

    hep-phhep-exJHEP(2023)·8 citations
17. 17*

    Domain Walls of Low Tension in Cosmology

    Holger Bech Nielsen🇩🇰 · Colin D. Froggatt🇬🇧

    In the present article we put up for discussion the idea of there existing several versions, phases, of the vacuum, in the spirit in which we have long worked on this idea, namely the Multiple Point Criticality Principle, which also says that these different vacuum phases have the same energy density. We mention that we indeed predicted the Higgs mass to be 135 plus minus 10 GeV, which when measured turned out to be 125 GeV, using the assumption of this Multiple Point Criticality Principle. We consider the possibility that there is one type of vacuum in the galaxy clusters (the usual vacuum) and another type of vacuum in the voids. The hope that there could indeed be such a low tension S of the domain wall between these two phases, that it would not totally upset cosmology is based on our dark matter model. In this model dark matter consists of pearls or bubbles of a new vacuum phase, with ordinary matter inside it under very high pressure. The order of magnitude of cubic root S of order MeV or 100 MeV could make such domain walls astronomically viable. We successfully estimate the order of magnitude of the variations in the fine structure constant in different places astronomically, but the similar variations in proton mass over electron mass should have been much bigger than seen experimentally in our model. The Universe s surprisingly early galaxies seen by JWST, James Webb telescope, may agree well with our model. Replacing the usual cosmological constant by domain walls in the standard cosmological model would lead to a cubic root of the tension being cubic root of S of order 30 MeV.

    ↳ astro-ph.COhep-phPoS(2023)·5 citations
18. 18*

    Numerical indication that center vortices drive dynamical mass generation in QCD

    Waseem Kamleh🇦🇺 · Derek B. Leinweber🇦🇺 · Adam Virgili🇦🇺

    The first calculation of the response of the momentum space quark propagator to center vortices in the ground state fields of QCD is presented. Center vortices are identified on 2+1-flavour dynamical gauge fields with $m_{\pi }\simeq 156$ MeV to obtain the vortex-removed and vortex-only quark propagator. Dynamical mass generation is found to vanish upon vortex removal, while the vortex-only field is able to generate dynamical mass. These new signatures strengthen the lattice QCD evidence indicating that center vortices underpin both dynamical chiral symmetry breaking and quark confinement.

    ↳ hep-lathep-phhep-thnucl-thPRD(2024)·12 citations
19. 19*

    Effects of multiple single-particle basis states in scattering systems

    Curtis D. Abell🇦🇺 · Derek B. Leinweber🇦🇺 · Anthony W. Thomas🇦🇺 · Jia-Jun Wu🇨🇳

    Low-lying baryon resonances have been explored using Hamiltonian Effective Field Theory (HEFT), in a formalism where resonances with a three-quark component are described by both two-particle meson-baryon states and a bare basis state. Here, we investigate the use of multiple bare states in the Hamiltonian, to extend the formalism to higher energy ranges, and represent a larger portion of the low-lying baryon spectrum. Introducing a second bare state into a toy model extension of the low-energy $\Delta (1232)$ system, we explore the influence of the second bare state on the position of poles in the infinite-volume $T$-matrix. Considering the same system in a finite-volume, we analyse the finite-volume energy spectrum in the presence of a second bare state, providing insight into the interplay between two bare basis states, representing quark-model states, and the relationship between infinite-volume poles and finite-volume eigenstates.

    ↳ nucl-thhep-lathep-phAnnals Phys.(2023)·12 citations
20. 20*

    Rapid identification of time-frequency domain gravitational wave signals from binary black holes using deep learning

    Yu-Xin Wang🇺🇸 · Shang-Jie Jin🇺🇸 · Tian-Yang Sun🇺🇸 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    Recent developments in deep learning techniques have offered an alternative and complementary approach to traditional matched filtering methods for the identification of gravitational wave (GW) signals. The rapid and accurate identification of GW signals is crucial for the progress of GW physics and multi-messenger astronomy, particularly in light of the upcoming fourth and fifth observing runs of LIGO-Virgo-KAGRA. In this work, we use the 2D U-Net algorithm to identify the time-frequency domain GW signals from stellar-mass binary black hole (BBH) mergers. We simulate BBH mergers with component masses from 5 to 80 $M_{\odot }$ and account for the LIGO detector noise. We find that the GW events in the first and second observation runs could all be clearly and rapidly identified. For the third observing run, about $80\%$ GW events could be identified. In particular, GW190814, currently unknown, is a special case that can be identified by the network, while other binary neutron star mergers and neutron star-black hole mergers can not be identified. Compared to the traditional convolutional neural network, the U-Net algorithm can output the time-frequency domain signal images rather than probabilities, providing a more intuitive investigation. Moreover, some of the results through U-Net can provide preliminary inference on the chirp mass information. In conclusion, the U-Net algorithm can rapidly identify the time-frequency domain GW signals from BBH mergers and potentially be helpful for future parameter inferences.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phCPC(2024)·20 citations
21. 21*

    Thermal QCD in a non-uniform magnetic background

    B. B. Brandt🇩🇪 · F. Cuteri🇩🇪 · G. Endrődi🇩🇪 · G. Markó🇩🇪 · L. Sandbote🇩🇪 · A. D. M. Valois🇩🇪

    Off-central heavy-ion collisions are known to feature magnetic fields with magnitudes and characteristic gradients corresponding to the scale of the strong interactions. In this work, we employ equilibrium lattice simulations of the underlying theory, QCD, involving similar inhomogeneous magnetic field profiles to achieve a better understanding of this system. We simulate three flavors of dynamical staggered quarks with physical masses at a range of magnetic fields and temperatures, and extrapolate the results to the continuum limit. Analyzing the impact of the field on the quark condensate and the Polyakov loop, we find non-trivial spatial features that render the QCD medium qualitatively different as in the homogeneous setup, especially at temperatures around the transition. In addition, we construct leading-order chiral perturbation theory for the inhomogeneous background and compare its prediction to our lattice results at low temperature. Our findings will be useful to benchmark effective theories and low-energy models of QCD for a better description of peripheral heavy-ion collisions.

    ↳ hep-lathep-exhep-phhep-thJHEP(2023)·24 citations
22. 22*

    Flavor, CP and Metaplectic Modular Symmetries in Type IIB Chiral Flux Vacua

    Takafumi Kai🇯🇵 · Keiya Ishiguro🇯🇵 · Hiroshi Okada🇰🇷 · Hajime Otsuka🇯🇵

    We examine symmetries of chiral four-dimensional vacua of Type IIB flux compactifications with vanishing superpotential $W=0$. We find that the $\mathcal{N}=1$ supersymmetric MSSM-like and Pati-Salam vacua possess enhanced discrete symmetries in the effective action below the mass scale of stabilized complex structure moduli and dilaton. Furthermore, a generation number of quarks/leptons is small on these vacua where the flavor, CP and metaplectic modular symmetries are described in the framework of eclectic flavor symmetry.

    ↳ hep-thhep-phJHEP(2023)·9 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.