Fri·Apr 8, 2022Friday·April 8, 2022

1. 01*

   Single Inclusive Jet Production in $pA$ Collisions at NLO in the small-$x$ regime

   Hao-yu Liu🇨🇳 · Kexin Xie🇨🇳 · Zhongbo Kang🇺🇸 · Xiaohui Liu🇨🇳

   We present the first complete NLO prediction with full jet algorithm implementation for the single inclusive jet production in $pA$ collisions within the CGC effective theory. Our prediction is fully differential over the final state physical kinematics, which allows the implementation of any IR safe observable including the jet clustering procedure. The NLO calculation is organized with the aid of the power counting proposed in [1] which gives rise to the novel soft contributions in the CGC factorization. We achieve the fully-differential calculation by constructing suitable subtraction terms to handle the singularities in the real corrections. The subtraction contributions can be exactly integrated analytically. We present the NLO cross section with the jets constructed using the anti-$k_T$ algorithm. The NLO calculation demonstrates explicitly the validity of the CGC factorization in jet production. Furthermore, as a byproduct of the subtraction method, we also derive the fully analytic cross section for the forward jet production in the small-$R$ limit. We show that in the small-$R$ approximation, the forward jet cross section can be factorized into a semi-hard cross section that produces a parton and the semi-inclusive jet functions. We argue that this feature holds for generic jet production and jet substructure observables in the CGC framework. Last, we show numerical analyses of the derived formula to validate our calculations. We justify when the small-$R$ approximation is appropriate. Like forward hadron production, the obtained NLO result also exhibits the negativity of the cross section in the large jet transverse regime, which signals the need for the threshold resummation. A sketch of the threshold resummation in the CGC framework is presented based on the multiple emission picture.

   hep-phhep-exnucl-exnucl-thJHEP(2022)·28 citations
2. 02*

   Investigation of ${\Delta }^0{\Delta }^0$ dibaryon in QCD

   H. Mutuk🇹🇷 · K. Azizi🇮🇷

   We study a hypothetical ${\Delta }^0{\Delta }^0$ dibaryon state by means of QCD sum rule method. We construct a scalar interpolating current to extract the mass and decay constant of this state taking into account contributions of various quark, gluon and mixed vacuum condensates. The predictions for the mass and decay constants are $m_D=2326_{-126}^{+114}\mathrm{MeV}$ and $f_D=2.94_{-0.34}^{+0.30}\times 10^{-4}{\mathrm{GeV}}^7$, respectively. We also made an estimation about binding energy and size of the ${\Delta }^0{\Delta }^0$ dibaryon. The obtained mass value is below the ${\Delta }^0{\Delta }^0$ threshold and may be a good dibaryon candidate for being observed experimentally.

   hep-phhep-exhep-latPRD(2022)·6 citations
3. 03*

   New Directions in the Search for Dark Matter

   Surjeet Rajendran🇺🇸

   The identification of the nature of dark matter is one of the most important problems confronting particle physics. Current observational constraints permit the mass of the dark matter to range from $10^{-22}$ eV - $10^{48}$ GeV. Given the weak nature of these bounds and the ease with which dark matter models can be constructed, it is clear that the problem can only be solved experimentally. In these lectures, I discuss methods to experimentally probe a wide range of dark matter candidates.

   hep-phastro-ph.COquant-phSciPost Phys.Lect.Notes(2022)·7 citations
4. 04*

   Heavy-Flavor-Conserving Hadronic Weak Decays of Charmed and Bottom Baryons

   Hai-Yang Cheng🇹🇼 · Fanrong Xu🇨🇳

   Three decades ago, heavy-flavor-conserving (HFC) weak decays of heavy baryons such as ${\Xi }_Q\to {\Lambda }_Q\pi$ and ${\Omega }_Q\to {\Xi }_Q\pi$ for $Q=c,b$ had been studied within the framework that incorporates both heavy-quark and chiral symmetries. It was pointed out that if the heavy quark in the HFC process behaves as a spectator, then the $P$-wave amplitude of ${\mathcal{B}}_{\bar{3}}\to {\mathcal{B}}_{\bar{3}}+\pi$ with ${\mathcal{B}}_{\bar{3}}$ being an antitriplet heavy baryon will vanish in the heavy quark limit. Indeed, this is the case for ${\Xi }_b\to {\Lambda }_b\pi$ decays. For ${\Xi }_c\to {\Lambda }_c\pi$ decays, they receive additional nonspectator contributions arising from the $W$-exchange diagrams through the $cs\to dc$ transition. Spectator and nonspectator $W$-exchange contributions to the $S$-wave amplitude of ${\Xi }_c\to {\Lambda }_c\pi$ are destructive, rendering the $S$-wave contribution even smaller. However, the nonspectator effect on the $P$-wave amplitude was overlooked in all the previous model calculations until a very recent investigation within the framework of a constituent quark model in which the parity-conserving pole terms were found to be dominant in ${\Xi }_c\to {\Lambda }_c\pi$ decays. Since the pion produced in the HFC process is soft, we apply current algebra to study both $S$- and $P$-wave amplitudes and employ the bag and diquark models to estimate the matrix elements of four-quark operators. We confirm that ${\Xi }_c\to {\Lambda }_c\pi$ decays are indeed dominated by the parity-conserving transition induced from nonspectator $W$-exchange and that they receive largest contributions from the intermediate ${\Sigma }_c$ pole terms. We also show that the $S$-wave of ${\Omega }_b\to {\Xi }_b\pi$ decays vanishes in the heavy quark limit, while ${\Omega }_c\to {\Xi }_c\pi$ receive additional $W$-exchange contributions via $cs\to dc$ transition.

   hep-phhep-exPRD(2022)·16 citations
5. 05*

   Muon Electric Dipole Moment as a Probe of Flavor-Diagonal CP Violation

   Yuichiro Nakai🇨🇳 · Ryosuke Sato🇯🇵 · Yoshihiro Shigekami🇨🇳

   Electric dipole moments (EDMs) of elementary particles are powerful probes of new physics with flavor-diagonal CP violation. The reported discrepancy in the muon anomalous magnetic moment motivates us to explore to what extent new physics with flavor-diagonal CP violation to address the discrepancy is probed by searches for the muon EDM. As a benchmark, we focus on a CP-violating two-Higgs-doublet model to explain the muon $g-2$ anomaly where the muon exclusively couples to one Higgs doublet. Since contributions to flavor violating processes as well as the electron EDM are suppressed, the muon EDM becomes an essential probe of the model. Our result shows that some viable parameter space leads to the muon EDM of around $d_{\mu }\simeq 6\times 10^{-23}e\mathrm{cm}$ probed by the PSI experiment and most of the parameter space is covered by the proposed J-PARC experiment.

   hep-phhep-exPLB(2022)·11 citations
6. 06*

   Universal Treatment of Reduction for One-Loop Integrals in Projective Space

   Bo Feng🇨🇳 · Jianyu Gong🇨🇳 · Tingfei Li🇨🇳

   Recently a nice work about the understanding of one-loop integrals has been done in [1] using the tricks of the projective space language associated to their Feynman parametrization. We find this language is also very suitable to deal with the reduction problem of one-loop integrals with general tensor structures as well as propagators with arbitrary higher powers. In this paper, we show that how to combine Feynman parametrization and embedding formalism to give a universal treatment of reductions for general one-loop integrals, even including the degenerated cases, such as the vanishing Gram determinant. Results from this method can be written in a compact and symmetric form.

   hep-phhep-thPRD(2022)·10 citations
7. 07*

   Amplitude Factorization in the Electroweak Standard Model

   Simon Plätzer🇦🇹 · Malin Sjodahl🇸🇪

   We lay out the basis of factorization at the amplitude level for processes involving the entire Standard Model. The factorization appears in a generalized eikonal approximation in which we expand around a quasi-soft limit for massive gauge bosons, fermions, and scalars. We use the chirality-flow formalism to express loop exchanges or emissions as operators on chiral structures. This forms the basis for amplitude evolution with parton exchange and branching in the full Standard Model, including the electroweak sector.

   hep-phPRD(2024)·8 citations
8. 08*

   Dark radiation as a probe for phase transition in the early universe

   Zihang Wang🇨🇳 · Lijing Shao🇨🇳

   The cosmological constant is not necessarily small in the early universe. If a scalar field obtains a vacuum expectation value after a phase transition (PT), a possibly large cosmological constant could present before PT. The early cosmological constant (ECC) and the PT process may be detectable from dark radiation (DR) today, such as in the cosmic axion background. We show that for a broad class of DR models, the DR density and spectrum are significantly modified by the presence of an ECC. From the density and the spectrum of the DR today, we can deduce the temperature and the strength of the PT.

   hep-phastro-ph.COPRD(2022)·0 citations
9. 09*

   Active-Sterile neutrino masses and mixings in $A_4$ minimal extended seesaw mechanism

   M. Kishan Singh🇮🇳 · S. Robertson Singh🇮🇳 · N. Nimai Singh🇮🇳

   Assuming the existence of an eV or KeV scale sterile neutrino, we develop a 3+1 neutrino mass model using $A_4\times Z_4\times Z_2$ symmetry group. Three Higgs $H,H^{\prime }$ and $H^{\prime \prime }$ are considered to give a desired neutrino mass matrix which generates non-zero ${\theta }_{13}$. The model can give neutrino mixing parameters that are well within the experimental 3$\sigma$ bounds. We also calculate the $4\times 4$ active-sterile neutrino mixing matrix, and it is found to be consistent with experimental bounds.

   hep-phInt.J.Theor.Phys.(2022)·7 citations
10. 10*

    Thermodynamic and cosmological parameters of early stages of the Universe

    Amr Abd Al-Rahman Youssef🇪🇬 · Gaber Faisel🇹🇷 · Hakan Akyildirim🇹🇷

    The early Universe was characterized by the presence of heavy particles that decoupled at different temperatures leading to different phases of the Universe. This had a consequences on the time evolution of the thermodynamic and the cosmological parameters characterizing each phase of the early Universe. In this study, we derive the analytic expressions of the equations governing the time evolution of these parameters in the early eras of the Universe namely, the radiation era, the quark-gluon plasma era, the hadron era and the mixed era. The parameters under concern include the energy density, the entropy density, the temperature, the pressure in addition to Hubble parameter and the scale factor. Having these expressions allows us to give estimations of the times corresponding to the beginning and ending of each era of the Universe as will be presented in this work.

    hep-phgr-qcMod.Phys.Lett.A(2023)·0 citations
11. 11*

    The depleted Higgs boson: searches for universal coupling suppression, invisible decays, and mixed-in scalars

    Prudhvi N. Bhattiprolu🇺🇸 · James D. Wells🇺🇸

    Two simple ways by which the standard signals of the Standard Model Higgs boson can be depleted are: its couplings to fermions and gauge bosons can be suppressed by a universal factor, and part of its branching fraction can be drained into invisible final states. A large class of theories can impose one or both of these depletion factors, even if mild, by way of additional scalar bosons that are singlets under the Standard Model but mix with the Higgs boson. We perform a comprehensive survey of the present status of the depleted Higgs boson, and discuss future prospects for detecting the presence of either depletion factor. We also survey the constraints status and future detection prospects for the generic case of extra mixed-in scalars which generically lead to these depletion factors for the Higgs boson. We find, for example, that precision study of the Higgs boson in many cases is more powerful than searches for the extra scalar states, given the slate of next-generation experiments that are on the horizon.

    hep-phPRD(2023)·8 citations
12. 12*

    Light Cone Sum Rules and Form Factors for $p\to e^{+}\gamma$

    Anshika Bansal🇮🇳 · Namit Mahajan🇮🇳

    Proton decay is a baryon number violating process, and hence is forbidden in the Standard Model (SM) of particle physics. Baryon number violation is expected to be an important criteria to explain the matter-anti-matter asymmetry of the universe. Any detection of the proton decay will be a direct evidence of physics beyond the SM. In SMEFT, proton decay is possible via baryon number violating dimension-6 operators. In this work, we pay attention to the decay channel $p\to e^{+}\gamma$ which is expected to be an experimentally cleaner channel due to less nuclear absorption. The gauge invariant amplitude of this process involves two form factors. We calculate these form factors in the framework of light cone sum rules (LCSR) using photon DAs upto two particle twist-3 accuracy as well as proton DAs of twist-3 accuracy. We find that the form factors calculated using photon DAs are more reliable.

    hep-phhep-exJHEP(2022)·4 citations
13. 13*

    Two-loop scattering amplitude for heavy-quark pair production through light-quark annihilation in QCD

    Manoj K. Mandal🇮🇹 · Pierpaolo Mastrolia🇮🇹 · Jonathan Ronca🇮🇹 · William J. Torres Bobadilla🇩🇪

    We present the first full analytic evaluation of the scattering amplitude for the process $q\bar{q}\to Q\bar{Q}$ up-to two loops in Quantum Chromodynamics, for a massless $(q)$ and a massive $(Q)$ quark flavour. The interference terms of the one- and two-loop amplitudes with the Born amplitude, decomposed in terms of gauge invariant form factors depending on the colour and flavour structure, are analytically calculated by keeping complete dependence on the squared center-of-mass energy, the squared momentum transfer, and the heavy-quark mass. The results are expressed as Laurent series around four space-time dimensions, with coefficients given in terms of generalised polylogarithms and transcendental constants up-to weight four. Our results validate the known, purely numerical calculations of the squared amplitude, and extend the analytic knowledge, previously limited to a subset of form factors, to their whole set, coming from both planar and non-planar diagrams, up-to the second order corrections in the strong coupling constant.

    hep-phhep-exhep-thJHEP(2022)·19 citations
14. 14*

    Measurements of $\mu \to 3e$ Decay with Polarised Muons as a Probe of New Physics

    P. D. Bolton🇮🇹 · S. T. Petcov🇮🇹

    Working within the Standard Model effective field theory approach, we examine the possibility to test charged lepton flavour violating (cLFV) new physics (NP) by angular measurements of the outgoing electron and positrons in the polarised ${\mu }^{+}\to e^{+}{e}^{+}{e}^{-}$ decay. This decay is planned to be studied with a sensitivity to the branching ratio of $B_{\mu \to 3e}\sim 10^{-15}$ by the Mu3e experiment at PSI. To illustrate the potential of these measurements, we consider a set of eight effective operators generating the decay at the tree level, including dimension-five dipole operators and dimension-six scalar and vector four-fermion operators of different chiralities. We show that if the polarised ${\mu }^{+}\to e^{+}{e}^{+}{e}^{-}$ decay is observed and is induced by a single operator, data from three angular observables - two P-odd asymmetries and one T-odd asymmetry - can allow to discriminate between all considered operators with the exception of scalar and vector operators of opposite chirality. For these two types of operators, the P-odd asymmetry is maximal in magnitude; they can be distinguished, in principle, by measuring the helicities of the outgoing positrons. The observation of a non-zero T-odd asymmetry would indicate the presence in the decay rate of a dipole and vector operator interference term that is T (CP) violating.

    hep-phPLB(2022)·17 citations
15. 15*

    A Fermionic Portal to Vector Dark Matter from a New Gauge Sector

    Alexander Belyaev🇬🇧 · Aldo Deandrea🇫🇷 · Stefano Moretti🇬🇧 · Luca Panizzi🇬🇧 · Douglas A. Ross🇬🇧 · Nakorn Thongyoi🇬🇧

    We present a new class of Dark Matter (DM) models wherein the Standard Model (SM) is extended with a new $SU(2{)}_D$ dark gauge sector. In this framework the stability of DM is provided by the conservation of a $U(1)$ global symmetry, which upon appropriate charge assignments for the $SU(2{)}_D$ multiplets, effectively leads to a ${\mathbb{Z}}_2$ symmetry subgroup. The origin of the global $U(1)$ symmetry which ensures the stability of DM can be justified in the form of a dark EW sector or through an underlying composite structure. The key ingredient of the model is a Vector-Like (VL) fermion doublet of $SU(2{)}_D$ , the members of which are singlets of the SM Electro-Weak (EW) gauge group, which mediate the interactions between the dark sector and the SM, via new Yukawa interactions. This class of models, labelled as Fermion Portal Vector DM (FPVDM), allows multiple realisations, depending on the properties of the the VL partner and the scalar potential. After spontaneous breaking of the $SU(2{)}_D$ symmetry via a new scalar doublet, the ensuing massive vector bosons with non-zero dark-isospin are DM candidates. The new class of FPVDM models suggested here has numerous phenomenological implications for collider and non-collider studies. As a practical example, we discuss here in detail a realisation involving a VL top partner assuming no mixing between the two physical scalars of the theory, the SM Higgs boson and its counterpart in the dark sector. We thus provide bounds on this setup from both collider and astroparticle observables.

    hep-phPRD(2023)·25 citations
16. 16*

    ALP Searches at the LHC: FASER as a Light Shining through Walls Experiment

    Felix Kling🇩🇪 · Pablo Quílez🇩🇪

    We propose the use of FASER as a light-shining-through-walls experiment to search for axions and axion-like particles (ALPs). LHC collisions generate a high intensity and high energy photon flux in the forward direction which can oscillate into ALPs in the magnetic fields that are used to confine the beam. These ALPs then pass through about 100~m of rock before reaching the magnetic fields of FASER, where they can convert back into photons and be detected by an electromagnetic calorimeter. In the next years, FASER and its successor FASER2 at the Forward Physics Facility will be able to explore regions of the ALPs parameter space inaccessible by other laboratory-based experiments.

    hep-phhep-exPRD(2022)·28 citations
17. 17*

    Influence of light quark loops on the Wigner phase with Dyson-Schwinger equations approach

    Jing-Hui Huang🇨🇳 · Xiang-Yun Hu🇨🇳 · Qi Wang🇨🇳 · Xue-Ying Duan🇨🇳 · Guang-Jun Wang🇨🇳 · Huan Chen🇨🇳

    We study the influence of light quark loops on the Wigner phase by solving coupled Dyson-Schwinger equations for quark propagator and gluon propagator. We take the gluon propagator in the Nambu phase from $N_f$ = 2 unquenched lattice QCD and choose various phenomenological models for the quark-gluon vertex. The gluon propagator in Winger phase is assumed to be different from that in the Nambu phase only due to the vacuum polarization of the quark loop. We obtain the Wigner solution of the coupled equations, compared with that from solving only the equation of the quark propagator. We discussed the corrections by the light quark loops and the dependence on various models of the quark-gluon vertex.

    hep-phhep-thEPJA(2022)·1 citation
18. 18*

    The Bottom-Up EFT: Complete UV Resonances of the SMEFT Operators

    Hao-Lin Li🇨🇳 · Yu-Han Ni🇨🇳 · Ming-Lei Xiao🇨🇳 · Jiang-Hao Yu🇨🇳

    The standard model effective field theory (SMEFT) provides systematic parameterization of all possible new physics above the electroweak scale. According to the amplitude-operator correspondence, an effective operator can be decomposed into a linear combination of several j-basis operators, which correspond to local amplitudes carrying certain spin and gauge quantum numbers in a particular scattering channel. Based on the Poincare and gauge symmetries of scattering amplitude, we construct the j-basis using the Casimir method for both the Lorentz and gauge sectors. The quantum numbers of the j-basis operators fix the quantum numbers of any intermediate state in the corresponding amplitudes, such as a UV resonance. This can be re-interpreted as the j-basis/UV correspondence, thus obtaining the j-bases in all partitions of fields for an operator amounts to finding all of its UV origins at tree level, constituting the central part of the bottom-up EFT framework. Applying the j-basis analysis to SMEFT, we obtain a complete list of possible tree-level UV origins of the effective operators at the dimension 5, 6, 7, and all the bosonic operators at the dimension 8.

    hep-phhep-thJHEP(2022)·31 citations
19. 19*

    Deviation to the Tri-Bi-Maximal flavor pattern and equivalent classes

    E. Barradas-Guevara🇲🇽 · O. Félix-Beltrán🇲🇽 · F. Gonzalez-Canales🇲🇽

    In the model-independent context, where the neutrino mass matrix is assumed to be diagonalized by means of a unitary matrix that possess the Tri-Bi-Maximal (TBM) flavor mixing pattern. We present an analysis where the TBM deviation is explored by considering different forms, with texture zeros, for the charged lepton mass matrix. These last mass matrices are classified into equivalent classes. We are interested in the charged lepton mass matrices with the minimum free parameter number, $i.e.$ the maximum number of texture zeros, that allows us to correctly reproduce the reactor mixing angle value. We show a deviation from the TBM pattern in terms of the charged lepton masses as well as the theoretical expressions and their parameter space for the mixing angles. Finally, we present the phenomenological implications of numerical values of the "Majorana-like" phase factors on the neutrinoless double-beta decay.

    hep-phInt.J.Mod.Phys.A(2023)·4 citations
20. 20*

    Discovery prospects for long-lived multiply charged particles at the LHC

    Mohammad Mahdi Altakach🇫🇷 · Priyanka Lamba🇵🇱 · Rafał Masełek🇵🇱 · Vasiliki A. Mitsou🇪🇸 · Kazuki Sakurai🇵🇱

    In this work, we aim to provide a comprehensive and largely model independent investigation on prospects to detect long-lived multiply charged particles at the LHC. We consider particles with spin 0 and $\frac{1}{2}$, with electric charges in range $1\le |Q/e|\le 8$, which are singlet or triplet under $SU(3{)}_C$. Such particles might be produced as particle-antiparticle pairs and propagate through detectors, or form a positronium(quarkonium)-like bound state. We consider both possibilities and estimate lower mass bounds on new particles, that can be provided by ATLAS, CMS and MoEDAL experiments at the end of Run 3 and HL-LHC data taking periods. We find out that the sensitivities of ATLAS and CMS are generally stronger than those of MoEDAL at Run 3, while they may be competitive at HL-LHC for $3\lesssim |Q/e|\lesssim 7$ for all types of long-lived particles we consider.

    hep-phhep-exEPJC(2022)·29 citations
21. 21*

    Fingerprints of freeze-in dark matter in an early matter-dominated era

    Avik Banerjee🇸🇪 · Debtosh Chowdhury🇮🇳

    We study the impact of an alternate cosmological history with an early matter-dominated epoch on the freeze-in production of dark matter. Such early matter domination is triggered by a meta-stable matter field dissipating into radiation. In general, the dissipation rate has a non-trivial temperature and scale factor dependence. Compared to the usual case of dark matter production via the freeze-in mechanism in a radiation-dominated universe, in this scenario, orders of magnitude larger coupling between the visible and the dark sector can be accommodated. Finally, as a proof of principle, we consider a specific model where the dark matter is produced by a sub-GeV dark photon having a kinetic mixing with the Standard Model photon. We point out that the parameter space of this model can be probed by the experiments in the presence of an early matter-dominated era.

    hep-phastro-ph.COastro-ph.HEhep-exSciPost Phys.(2022)·22 citations
22. 22*

    Time Evolution in Quantum Cosmology

    Anne-Katherine Burns🇺🇸 · David E. Kaplan🇺🇸 · Tom Melia🇯🇵 · Surjeet Rajendran🇺🇸

    The quantum description of time evolution in non-linear gravitational systems such as cosmological space-times is not well understood. We show, in the simplified setting of mini-superspace, that time evolution of this system can be obtained using a gauge fixed path integral, as long as one does not integrate over proper time. Using this gauge fixed action we can construct a Hamiltonian in the coherent - or classical - state basis. We show that by construction the coherent states satisfy the classical dynamical equations of General Relativity. They do not satisfy the Hamiltonian constraint. A consequence of this is that the Wheeler-DeWitt equation should not be satisfied in quantum gravity. Classical states have a natural non-trivial time evolution since they are not eigenstates of the Hamiltonian. A general feature of the unconstrained quantum theory of gravity is the prediction of a pressureless dark matter component of either sign energy density in the classical universe which may lead to novel phenomenology.

    ↳ gr-qchep-phhep-th10 citations
23. 23*

    Highlights on Supersymmetry and Exotic Searches at the LHC

    Sezen Sekmen (on behalf of the ATLAS, CMS and LHCb Collaborations)🇰🇷

    The Run 2 data taking period of the Large Hadron Collider (LHC) at CERN in years 2015-2018 has presented a great opportunity to search for physics beyond the standard model (BSM). It will be followed by the Run 3 period starting in 2022, and by the High-Luminosity LHC (HL-LHC) era starting in late 2020s, where the latter promises an unprecedented wealth of physics prospects due to very high expected integrated luminosity and improved detector features. The ATLAS, CMS and LHCb experiments pursued a rich physics program in Run 2, and are already assessing the physics expectations at the HL-LHC era. This report presents highlights from recent search results and HL-LHC studies on BSM physics by the ATLAS, CMS and LHCb experiments. Examples will be shown from model-independent generic searches, searches for supersymmetry, extended Higgs sectors, and new exotic fermions and bosons.

    ↳ hep-exhep-ph11 citations
24. 24*

    Radiative hadronization: Photon emission at hadronization from quark-gluon plasma

    Hirotsugu Fujii🇯🇵 · Kazunori Itakura🇯🇵 · Katsunori Miyachi🇯🇵 · Chiho Nonaka🇯🇵

    We investigate photon emission at the hadronization stage from a quark-gluon plasma created in relativistic heavy-ion collisions. A recombination-model picture suggests that a quark and an antiquark bind into a meson state in hadronization, which would apparently violate the energy conservation if there is nothing else involved. We consider here a hadronization process where the recombination accompanies a photon emission. This is an analog of the "{\it radiative recombination}" known in plasma physics, such as $e^{-}+p^{+}\to {\mathrm{H}}^0+\gamma$, which occurs when an electromagnetic plasma goes back to a neutral atomic gas. The "radiative hadronization" picture will bring about (i) an enhancement of the photon yield, (ii) significant flow of photons similar to that of hadrons, and (iii) the photon transverse momentum ($p_T$) distribution with a thermal profile whose effective temperature is given by blue-shifted temperature of quarks. Here as a simplest and phenomenological realization of the radiative hadronization, we modify the recombination model to involve a photon emission and evaluate the photon yield with this modified model. Adding this contribution to the direct photon yield along with thermal photon contribution calculated with a hydrodynamic model and a parametrized contribution of prompt photons, we study the $p_T$ spectrum and elliptic flow of the photons produced in heavy-ion collisions at RHIC and LHC energies.

    ↳ nucl-thhep-phnucl-exPRC(2022)·15 citations
25. 25*

    Implications of the Non-Observation of ${}^6\mathrm{Li}$ in Halo Stars for the Primordial ${}^7\mathrm{Li}$ Problem

    Brian D. Fields🇺🇸 · Keith A. Olive🇺🇸

    The primordial Lithium Problem is intimately connected to the assumption that ${}^7\mathrm{Li}$ observed in metal-poor halo stars retains its primordial abundance, which lies significantly below the predictions of standard big-bang nucleosynthesis. Two key lines of evidence have argued that these stars have not significantly depleted their initial ${}^7\mathrm{Li}$: i) the lack of dispersion in Li abundances measured at low metallicity; and ii) the detection of the more fragile ${}^6\mathrm{Li}$ isotope in at least two halo stars. The purported ${}^6\mathrm{Li}$ detections were in good agreement with predictions from cosmic-ray nucleosynthesis which is responsible for the origin of ${}^6\mathrm{Li}$. This concordance left little room for depletion of ${}^6\mathrm{Li}$ depletion, and implied that the more robust ${}^7\mathrm{Li}$ largely evaded destruction. Recent (re)-observations of halo stars challenge the evidence against ${}^7\mathrm{Li}$ depletion: i) lithium abundances now show significant dispersion, and ii) sensitive ${}^6\mathrm{Li}$ searches now reveal only firm upper limits to the ${}^6\mathrm{Li}/{}^7\mathrm{Li}$ ratio. The tight new ${}^6\mathrm{Li}$ upper limits generally fall far below the predictions of cosmic-ray nucleosynthesis, implying that substantial ${}^6\mathrm{Li}$ depletion has occurred--by factors up to 50. We show that in stars with ${}^6\mathrm{Li}$ limits and thus lower bounds on ${}^6\mathrm{Li}$ depletion, an equal amount of ${}^7\mathrm{Li}$ depletion is more than sufficient to resolve the primordial ${}^7\mathrm{Li}$ Problem. This picture is consistent with stellar models in which ${}^7\mathrm{Li}$ is less depleted than ${}^6\mathrm{Li}$, and strengthen the case that the Lithium Problem has an astrophysical solution. We conclude by suggesting future observations that could test these ideas. (abridged)

    ↳ astro-ph.GAastro-ph.COastro-ph.SRhep-phJCAP(2022)·39 citations
26. 26*

    Quantum Simulation for High Energy Physics

    Christian W. Bauer🇺🇸 · Zohreh Davoudi🇺🇸 · A. Baha Balantekin🇺🇸 · Tanmoy Bhattacharya🇺🇸 · Marcela Carena🇺🇸 · Wibe A. de Jong🇺🇸 · Patrick Draper🇺🇸 · Aida El-Khadra🇺🇸 · Nate Gemelke🇺🇸 · Masanori Hanada🇬🇧 · Dmitri Kharzeev🇺🇸 · Henry Lamm🇺🇸 and 19 other authors

    It is for the first time that Quantum Simulation for High Energy Physics (HEP) is studied in the U.S. decadal particle-physics community planning, and in fact until recently, this was not considered a mainstream topic in the community. This fact speaks of a remarkable rate of growth of this subfield over the past few years, stimulated by the impressive advancements in Quantum Information Sciences (QIS) and associated technologies over the past decade, and the significant investment in this area by the government and private sectors in the U.S. and other countries. High-energy physicists have quickly identified problems of importance to our understanding of nature at the most fundamental level, from tiniest distances to cosmological extents, that are intractable with classical computers but may benefit from quantum advantage. They have initiated, and continue to carry out, a vigorous program in theory, algorithm, and hardware co-design for simulations of relevance to the HEP mission. This community whitepaper is an attempt to bring this exciting and yet challenging area of research to the spotlight, and to elaborate on what the promises, requirements, challenges, and potential solutions are over the next decade and beyond.

    ↳ quant-phhep-lathep-phhep-th+1PRX Quantum(2023)·568 citations
27. 27*

    Droplet collapse during strongly supercooled transitions

    Daniel Cutting🇫🇮 · Essi Vilhonen🇫🇮 · David J. Weir🇫🇮

    We simulate the decay of isolated, spherically symmetric droplets in a cosmological phase transition. It has long been posited that such heated droplets of the metastable state could form, and they have recently been observed in 3D multi-bubble simulations. In those simulations, the droplets were associated with a reduction in the wall velocity and a decrease in the kinetic energy of the fluid, with a consequent suppression in the gravitational wave power spectrum. In the present work, we track the wall speed and kinetic energy production in isolated droplets and compare them to those found in multi-bubble collisions. The late-time wall velocities that we observe match those of the 3D simulations, though we find that the spherical simulations are a poor predictor of the kinetic energy production. This implies that spherically symmetric simulations could be used to refine baryogenesis predictions due to the formation of droplets, but not to estimate any accompanying suppression of the gravitational wave signal.

    ↳ astro-ph.COhep-phPRD(2022)·22 citations
28. 28*

    Constraints on the ultralight scalar boson from Advanced LIGO and Advanced Virgo's first three observing runs using the stochastic gravitational-wave background

    Chen Yuan🇨🇳 · Yang Jiang🇨🇳 · Qing-Guo Huang🇨🇳

    Ultralight bosons are promising dark matter candidates and can trigger superradiant instabilities of spinning black holes (BHs), resulting in long-lived rotating "bosonic clouds" around the BHs and dissipating their energy through the emission of monochromatic gravitational waves (GWs). We focus on the scalar bosons minimally coupled with both isolated stellar-origin BHs (SBH) and their binary merger remnants, and perform Bayesian data analysis to search for the stochastic GW background from all the unstable modes that can trigger the superradiant instabilities using the data of Advanced LIGO and Advanced Virgo's first three observing runs. We find no evidence for such signal, and hence rule out the scalar bosons within the mass range $[1.5,16]\times 10^{-13}$ eV, $[1.9,8.3]\times 10^{-13}$ eV and $[1.3,17]\times 10^{-13}$ eV at $95\%$ confidence level for isolated SBHs having a uniform dimensionless spin distribution in $[0,1]$, $[0,0.5]$ and $[0.5,1]$, respectively.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2022)·48 citations
29. 29*

    Density functional approach to quark matter with confinement and color superconductivity

    Oleksii Ivanytskyi🇵🇱 · David Blaschke🇵🇱

    We present a novel relativistic density-functional approach to modeling quark matter with a mechanism to mimic confinement. The quasiparticle treatment of quarks provides their suppression due to a large quark selfenergy already at the mean-field level. We demonstrate that our approach is equivalent to a chiral quark model with medium-dependent couplings. The dynamical restoration of the chiral symmetry is ensured by construction of the density functional. Supplemented with the vector repulsion and diquark pairing the model is applied to construct a hybrid quark-hadron EoS of cold compact-star matter. We study the connection of such a hybrid EoS with the stellar mass-radius relation and tidal deformability. The model results are compared to various observational constraints including the NICER radius measurement of PSR J0740+6620 and the tidal deformability constraint from GW170817. The model is shown to be consistent with the constraints, still allowing for further improvement by adjusting the vector repulsion and diquark pairing couplings.

    ↳ nucl-thastro-ph.HEhep-phPRD(2022)·63 citations
30. 30*

    Qade: Solving Differential Equations on Quantum Annealers

    Juan Carlos Criado🇬🇧 · Michael Spannowsky🇬🇧

    We present a general method, called Qade, for solving differential equations using a quantum annealer. The solution is obtained as a linear combination of a set of basis functions. On current devices, Qade can solve systems of coupled partial differential equations that depend linearly on the solution and its derivatives, with non-linear variable coefficients and arbitrary inhomogeneous terms. We test the method with several examples and find that state-of-the-art quantum annealers can find the solution accurately for problems requiring a small enough function basis. We provide a Python package implementing the method at gitlab.com/jccriado/qade.

    ↳ quant-phcs.LGhep-phhep-thQuantum Sci.Technol.(2023)·28 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.