Fri·Jun 11, 2021Friday·June 11, 2021

1. 01*

   Azimuthal Angular Asymmetry of Soft Gluon Radiation in Jet Production

   Yoshitaka Hatta🇺🇸 · Bo-Wen Xiao🇨🇳 · Feng Yuan🇺🇸 · Jian Zhou🇨🇳

   We investigate the impact of soft gluon resummation on the azimuthal angle correlation between the total and relative momenta of two energetic final state particles (jets). We show that the initial and final state radiations induce sizable $\cos (\varphi )$ and $\cos (2\varphi )$ asymmetries in single jet and dijet events, respectively. We numerically evaluate the magnitude of these asymmetries for a number of processes in collider experiments, including diffractive dijet and dilepton production in ultraperipheral $pA$ and $AA$ collisions, inclusive and diffractive dijet production at the EIC and inclusive dijet production in $pp$ collisions at the LHC. In particular, the $\cos (2\varphi )$ asymmetry of perturbative origin can dominate over the primordial asymmetry due to the linearly polarized gluon distribution.

   hep-phPRD(2021)·98 citations
2. 02*

   Computing Light-Front Wave Functions Without Light-Front Quantization: A Large-Momentum Effective Theory Approach

   Xiangdong Ji🇺🇸 · Yizhuang Liu🇵🇱

   Light-front wave functions play a fundamental role in the light-front quantization approach to QCD and hadron structure. However, a naive implementation of the light-front quantization suffers from various subtleties including the well-known zero-mode problem, the associated rapidity divergences which mixes ultra-violet divergences with infrared physics, as well as breaking of spatial rotational symmetry. We advocate that the light-front quantization should be viewed as an effective theory in which small $k^{+}$ modes have been effectively ``integrated out'', with an infinite number of renormalization constants. Instead of solving light-front quantized field theories directly, we make the large momentum expansion of the equal-time Euclidean correlation functions in instant quantization as an effective way to systematically calculate light-front correlations, including the light-front wave function amplitudes. This large-momentum effective theory accomplishes an effective light-front quantization through lattice QCD calculations. We demonstrate our approach using an example of a pseudo-scalar meson wave function.

   hep-phhep-latnucl-exnucl-thPRD(2022)·60 citations
3. 03*

   A first next-to-next-to-leading order study of three-jet production at the LHC

   Michal Czakon🇩🇪 · Alexander Mitov🇬🇧 · Rene Poncelet🇬🇧

   Multi-jet rates at hadron colliders provide a unique possibility for probing Quantum Chromodynamics (QCD), the theory of strong interactions. By comparing theory predictions with collider data, one can directly test perturbative QCD, extract fundamental parameters like the strong coupling ${\alpha }_s$ and search for physics beyond the Standard Model. In this work we calculate, for the first time, the next-to-next-to-leading (NNLO) QCD corrections to typical three-jet observables and to differential three-to-two jet ratios. We demonstrate that the inclusion of the NNLO corrections significantly reduces the dependence of those observables on the factorization and renormalization scales. Besides its phenomenological value, this proof-of-principle computation represents a milestone in perturbative QCD.

   hep-phhep-exhep-thPRL(2021)·139 citations
4. 04*

   Dilepton production in the SMEFT at $\mathcal{O}(1/{\Lambda }^4)$

   Radja Boughezal🇺🇸 · Emanuele Mereghetti🇺🇸 · Frank Petriello🇺🇸

   We study the inclusion of $\mathcal{O}(1/{\Lambda }^4)$ effects in the Standard Model Effective Field Theory in fits to the current Drell-Yan data at the LHC. Our analysis includes the full set of dimension-6 and dimension-8 operators contributing to the dilepton process, and is performed to next-to-leading-order in the QCD coupling constant at both $\mathcal{O}(1/{\Lambda }^2)$ and $\mathcal{O}(1/{\Lambda }^4)$. We find that the inclusion of dimension-6 squared terms and certain dimension-8 operators has significant effects on fits to the current data. Neglecting them leads to bounds on dimension-6 operators off by large factors. We find that dimension-8 four-fermion operators can already be probed to the several-TeV level by LHC results, and that their inclusion significantly changes the limits found for dimension-6 operators. We discuss which dimension-8 operators should be included in fits to the LHC data. Only a manageable subset of two-derivative dimension-8 four-fermion operators need to be included at this stage given current LHC uncertainties.

   hep-phPRD(2021)·80 citations
5. 05*

   Current bounds on baryogenesis from complex Yukawa couplings of light fermions

   Shahaf Aharony Shapira🇮🇱

   We calculate the contribution to the baryon asymmetry of the Universe (BAU) from a $\mathcal{C}\mathcal{P}$-violating source of the light quarks (charm, strange, down, up) and the electron, resulting from a dimension-six effective field theory term. We derive relevant bounds from the electric dipole moments of the electron and neutron to estimate the maximal contribution from each single flavor modification. Current bounds show that the charm quark can generate at most $\mathcal{O}(1\%)$ of the BAU, while the lighter quarks and the electron contribute at much lower levels.

   hep-phastro-ph.COPRD(2022)·12 citations
6. 06*

   Quantum Gravity Effect on The Time History of The Universe

   I. A. Elmashad🇪🇬 · Asmaa G. Shalaby🇪🇬

   The QCD phase transition exhibits different periods during the evolution time of the universe. We explore the cosmological implications of QCD phase transition in the early universe, which was mainly full of QGP matter, through the Friedmann equations. This is performed by studying the effect of GUP on the MIT bag model. The obtained modified MIT bag model alongside with the Friedmann equations are utilized to study the thermodynamical quantities in terms of the evolution time. The effect of GUP is set by inserting the parameter $\alpha =10^{-5}Ge{V}^{-1}$. It is found that, the GUP effect on the evolution time of the universe makes it shorter, i.e the time span of each phase takes shorter time to transfer to another phase than their corresponding ones without GUP effect.

   hep-ph0 citations
7. 07*

   Lepton pair production in ultra-peripheral collisions

   Ren-jie Wang🇨🇳 · Shi Pu🇨🇳 · Qun Wang🇨🇳

   The lepton pair production in ultra-peripheral collisions (UPC) is studied in the classical field approximation. We derive a general form of the cross section in terms of photon distributions which depend on the transverse momentum and coordinate based on the wave packet form of nuclear wave functions. Such a general form of the cross section in the classical field approximation contains the results of the generalized equivalent photon approximation (EPA) as well as the corrections beyond EPA in the Born approximation. By rewriting the general form of the cross section in light-cone coordinates, we find a good connection with the transverse momentum dependent distribution (TMD) factorization formalism in the Born approximation. Our numerical results are consistent with current experimental data.

   hep-phnucl-thPRD(2021)·44 citations
8. 08*

   Mass spectra for the $cc\bar{b}\bar{b}$/$bb\bar{c}\bar{c}$ tetraquark states

   Qi-Nan Wang🇨🇳 · Zi-Heng Yang🇨🇳 · Wei Chen🇨🇳 · Hua-Xing Chen🇨🇳

   We have studied the masse spectra for the $cc\bar{b}\bar{b}$/$bb\bar{c}\bar{c}$ tetraquark states with quantum numbers $J^P=0^{\pm },1^{\pm }$, and $2^{+}$. We systematically construct the interpolating currents with various spin-parity quantum numbers and calculate their two-point correlation functions in the framework of QCD moment sum rule method. Our calculations show that the masses are about $12.3-12.4$ GeV for the positive parity $cc\bar{b}\bar{b}$ tetraquark ground states with $J^P=0^{+},1^{+},2^{+}$, while $12.8-13.1$ GeV for the negative parity channels with $J^P=0^{-},1^{-}$. The mass predictions for the positive parity $cc\bar{b}\bar{b}$ ground states are lower than the $B_c{B}_c$ threshold, implying that these tetraquarks can only decay via weak interaction and thus are expected to be stable and narrow.

   hep-phhep-exPRD(2021)·15 citations
9. 09*

   Small-momentum expansion of heavy-quark correlators in the large-${\beta }_0$ limit and ${\alpha }_s$ extractions

   Diogo Boito🇧🇷 · Vicent Mateu🇪🇸 · Marcus V. Rodrigues🇧🇷

   We calculate the small-momentum expansion of vector, axial-vector, scalar, and pseudo-scalar heavy-quark current correlators in the large-${\beta }_0$ limit of QCD, extending the analysis of Grozin and Sturm beyond the vector current. Our results are used to study the higher-order behaviour of dimensionless ratios of vector and pseudo-scalar moments used for the precise extraction of the strong coupling, ${\alpha }_s$, from relativistic quarkonium sum rules and lattice data, respectively. We show that these ratios benefit from a partial cancellation of the leading renormalon singularities. Our results can guide the design of combinations of moments with improved perturbative behaviour.

   hep-phhep-latJHEP(2021)·9 citations
10. 10*

    New interpretation of chiral phase transition: Violation of trilemma in QCD

    Chuan-Xin Cui🇨🇳 · Jin-Yang Li🇨🇳 · Shinya Matsuzaki🇨🇳 · Mamiya Kawaguchi🇨🇳 · Akio Tomiya🇺🇸

    We find that the chiral phase transition (chiral crossover) in QCD at physical point is triggered by big imbalance among three fundamental quantities essential for the QCD vacuum structure: susceptibility functions for the chiral symmetry, axial symmetry, and the topological charge. The balance, dobbed the QCD trilemma, is unavoidably violated when one of the magnitudes among them is highly dominated, or suppressed. Based on a three-flavor Nambu-Jona-Lasinio model, we explicitly evaluate the amount of violation of the QCD trilemma at physical point, and show that the violation takes place not only at vacuum, but even in a whole temperature regime including the chiral crossover epoch. This work confirms and extends the suggestion recently reported from lattice QCD with 2 flavors on dominance of the axial and topological susceptibilities left in the chiral susceptibility at high temperatures. It turns out that the imbalance is essentially due to the flavor symmetry violation of the lightest three flavors, and the flavor breaking specifically brings enhancement of the axial anomaly contribution in the chiral order parameter, while the the strength of the axial breaking and the transition rate of the topological charge are fairly insensitive to the flavor symmetry. The violation of QCD trilemma and its flavor dependence can be tested by lattice simulations with 2 + 1 flavors in the future, and would also give a new guiding principle to explore the flavor dependence of the chiral phase transition, such as the Columbia plot, including possible extension with external fields.

    hep-phhep-lathep-thPRD(2022)·13 citations
11. 11*

    Virtual Compton scattering at low energies with a positron beam

    B. Pasquini (U. Pavia and INFN, Pavia)🇮🇹 · M. Vanderhaeghen (U. Mainz, PRISMA)🇩🇪

    The Virtual Compton scattering (VCS) process at low energies explores the electromagnetic structure of the proton in terms of generalized polarizabilities (GPs). In the one-photon exchange approximation, VCS can be accessed with exclusive photon production reactions with electron or positron beams. The extraction of the GPs from VCS with electron beam has seen substantial progress over the past two decades. Nonetheless, a consistent picture of the GPs from low to higher scales demands further investigations. Complementary measurements with positron beams offer an unique possibility, and we present an impact study of such experimental program.

    hep-phhep-exnucl-exnucl-thEPJA(2021)·5 citations
12. 12*

    Event-by-event cumulants of azimuthal angles

    Ante Bilandzic🇩🇪

    We develop further the recently proposed event-by-event cumulants of azimuthal angles. The role of reflection symmetry, permutation symmetry, frame independence, and relabeling of particle indices in the cumulant expansion is discussed in detail. We argue that mathematical and statistical properties of cumulants are preserved if cumulants of azimuthal angles are defined event-by-event in terms of single-event averages of azimuthal angles, while they are violated in the traditional approach in which cumulants are defined in terms of all-event averages. We derive for the first time the example analytic solutions for the contribution of combinatorial background in the measured 2- and 3-particle correlations. We demonstrate that these solutions for the combinatorial background are universal as they can be written generically in terms of multiplicity-dependent combinatorial weights and marginal probability density functions of starting multivariate distribution. The new general results between multiparticle azimuthal correlators and flow amplitudes and symmetry planes are presented.

    hep-phhep-exnucl-exEPJC(2022)·5 citations
13. 13*

    Precision axion physics with running axion couplings

    Kiwoon Choi🇰🇷 · Sang Hui Im🇰🇷 · Hee Jung Kim🇰🇷 · Hyeonseok Seong🇰🇷

    We study the renormalization group running of axion couplings while taking into account that the Standard Model can be extended to its supersymmetric extension at a certain energy scale below the axion decay constant. We then apply our results to three different classes of axion models, i.e. KSVZ-like, DFSZ-like, and string-theoretic axions, and examine if string-theoretic axions can be distinguished from others by having a different pattern of low energy couplings to the photon, nucleons and electron. We find that the low energy couplings of string-theoretic axions have a similar pattern as those of KSVZ-like axions but yet reveal a sizable difference which might be testable in future axion search experiments. We also note that the coupling of KSVZ-like QCD axions to the electron is dominated by a three-loop contribution involving the exotic heavy quark, gluons, top quark and Higgs field.

    hep-phhep-exhep-thJHEP(2021)·38 citations
14. 14*

    Spectrum of Hidden-Charm, Open-Strange Exotics in the Dynamical Diquark Model

    Jesse F. Giron🇺🇸 · Richard F. Lebed🇺🇸 · Steven R. Martinez🇺🇸

    The observation by BESIII and LHCb of states with hidden charm and open strangeness ($c\bar{c}q\bar{s}$) presents new opportunities for the development of a global model of heavy-quark exotics. Here we extend the dynamical diquark model to encompass such states, using the same values of Hamiltonian parameters previously obtained from the nonstrange and hidden-strange sectors. The large mass splitting between $Z_{cs}(4000)$ and $Z_{cs}(4220)$ suggests substantial SU(3)${}_{\mathrm{flavor}}$ mixing between all $J^P=1^{+}$ states, while their average mass compared to that of other sectors offers a direct probe of flavor octet-singlet mixing among exotics. We also explore the inclusion of $\eta$-like exchanges within the states, and find their effects to be quite limited. In addition, using the same diquark-mass parameters, we find $P_c(4312)$ and $P_{cs}(4459)$ to fit well as corresponding nonstrange and open-strange pentaquarks.

    hep-phPRD(2021)·64 citations
15. 15*

    Hadronization Model Tuning in GENIE v3

    Júlia Tena-Vidal🇬🇧 · Costas Andreopoulos🇬🇧 · Christopher Barry🇬🇧 · Steve Dennis🇬🇧 · Steve Dytman🇺🇸 · Hugh Gallagher🇺🇸 · Steven Gardiner🇺🇸 · Walter Giele🇺🇸 · Robert Hatcher🇺🇸 · Or Hen🇺🇸 · Igor D. Kakorin🇷🇺 · Konstantin S. Kuzmin🇷🇺 and 6 other authors

    The GENIE neutrino Monte Carlo describes neutrino-induced hadronization with an effective model, known as AGKY, which is interfaced with PYTHIA at high invariant mass. Only the low-mass AGKY model parameters were extracted from hadronic shower data from the FNAL 15 ft and BEBC experiments. In this paper, the first hadronization tune on averaged charged multiplicity data from deuterium and hydrogen bubble chamber experiments is presented, with a complete estimation of parameter uncertainties. A partial tune on deuterium data only highlights the tensions between hydrogen and deuterium datasets.

    hep-phhep-exPRD(2022)·47 citations
16. 16*

    Constraints on dark matter annihilation from the Event Horizon Telescope Observations of M87${}^{\star }$

    Guan-Wen Yuan🇨🇳 · Zhan-Fang Chen🇨🇳 · Zhao-Qiang Shen🇨🇳 · Wen-Qing Guo🇨🇳 · Ran Ding🇨🇳 · Xiaoyuan Huang🇨🇳 · Qiang Yuan🇨🇳

    The fast developments of radio astronomy open a new window to explore the properties of Dark Matter (DM). The recent direct imaging of the supermassive black hole (SMBH) at the center of M87 radio galaxy by the Event Horizon Telescope (EHT) collaboration is expected to be very useful to search for possible new physics. In this work, we illustrate that such results can be used to detect the possible synchrotron radiation signature produced by DM annihilation from the innermost region of the SMBH. Assuming the existence of a spike DM density profile, we obtain the flux density due to DM annihilation induced electrons and positrons, and derive new limits on the DM annihilation cross section via the comparison with the EHT integral flux density at 230 GHz. Our results show that the parameter space can be probed by the EHT observations is largely complementary to other experiments. For DM with typical mass regions of being weakly interacting massive particles, the annihilation cross section several orders of magnitude below the thermal production level can be excluded by the EHT observations under the density spike assumption. Future EHT observations may further improve the sensitivity on the DM searches, and may also provide a unique opportunity to test the interplay between DM and the SMBH.

    hep-phastro-ph.HEJHEP(2022)·15 citations
17. 17*

    Particle-antiparticle asymmetry in a relativistic deformed kinematics

    José Manuel Carmona🇪🇸 · José Luis Cortés🇪🇸 · José Javier Relancio🇪🇸

    Relativistic deformed kinematics are usually considered as a way to capture residual effects of a fundamental quantum gravity theory. These kinematics present a non-commutative addition law for the momenta, so that the total momentum of a multi-particle system depends on the specific ordering in which the momenta are composed. We explore in the present work how this property may be used to generate an asymmetry between particles and antiparticles through a particular ordering prescription, resulting in a violation of CPT symmetry. We study its consequences for muon decay, obtaining a difference in the lifetimes of the particle and the antiparticle as a function the new high-energy scale parameterizing such a relativistic deformed kinematics.

    hep-phgr-qcSymmetry(2021)·7 citations
18. 18*

    Revisiting $K\to \pi a$ decays

    Alfredo Walter Mario Guerrera🇮🇹 · Stefano Rigolin🇮🇹

    The theoretical calculation for pseudo--scalars hadronic decays $K\to \pi a$ is reviewed. %with the Axion-Like-Particle escaping the detection, While one-loop penguin contributions are usually considered, tree-level processes have most often been overlooked in literature. Following the Lepage--Brodsky approach the tree-level contribution to the charged and neutral pseudo--scalar decay in ALP is estimated. Assuming generic ALP couplings to SM fermions, the latest NA62/E949 results for the $K^{+}\to {\pi }^{+}a$ decay and the present/future KOTO results for the $K_L^0\to {\pi }^{0}a$ decay are used to provide updated bounds on the ALP--fermion Lagrangian sector. Finally, the interplay between the tree-level and one-loop contributions is investigated.

    hep-phEPJC(2022)·35 citations
19. 19*

    Sterile Neutrinos

    Basudeb Dasgupta🇮🇳 · Joachim Kopp🇨🇭

    Neutrinos, being the only fermions in the Standard Model of Particle Physics that do not possess electromagnetic or color charges, have the unique opportunity to communicate with fermions outside the Standard Model through mass mixing. Such Standard Model-singlet fermions are generally referred to as "sterile neutrinos''. In this review article, we discuss the theoretical and experimental motivation for sterile neutrinos, as well as their phenomenological consequences. With the benefit of hindsight in 2020, we point out potentially viable and interesting ideas. We focus in particular on sterile neutrinos that are light enough to participate in neutrino oscillations, but we also comment on the benefits of introducing heavier sterile states. We discuss the phenomenology of eV-scale sterile neutrinos in terrestrial experiments and in cosmology, we survey the global data, and we highlight various intriguing anomalies. We also expose the severe tension that exists between different data sets and prevents a consistent interpretation of the global data in at least the simplest sterile neutrino models. We discuss non-minimal scenarios that may alleviate some of this tension. We briefly review the status of keV-scale sterile neutrinos as dark matter and the possibility of explaining the matter-antimatter asymmetry of the Universe through leptogenesis driven by yet heavier sterile neutrinos.

    hep-phastro-ph.COhep-exPhys.Rept.(2021)·289 citations
20. 20*

    Unitarity constraints on ALP interactions

    I. Brivio🇩🇪 · O. J. P. Éboli🇧🇷 · M. C. Gonzalez-Garcia🇺🇸

    We derive partial-wave unitarity constraints on gauge-invariant interactions of an Axion-Like Particle (ALP) up to dimension-6 from all allowed $2\to 2$ scattering processes in the limit of large center-of-mass energy. We find that the strongest bounds stem from scattering amplitudes with one external ALP and only apply to the coupling to a pair of $SU(2{)}_L$ gauge bosons. Couplings to $U(1{)}_Y$ and $SU(3{)}_C$ gauge bosons and to fermions are more loosely constrained.

    hep-phPRD(2021)·25 citations
21. 21*

    Two-loop QCD penguin contribution to the width difference in $B_s-{\bar{B}}_s$ mixing

    Marvin Gerlach🇩🇪 · Ulrich Nierste🇩🇪 · Vladyslav Shtabovenko🇩🇪 · Matthias Steinhauser🇩🇪

    We consider two-loop QCD corrections to the element ${\Gamma }_{12}^q$ of the decay matrix in $B_q-{\bar{B}}_q$ mixing, $q=d,s$, in the leading power of the Heavy Quark Expansion. The calculated contributions involve one current-current and one penguin operator and constitute the next step towards a theory prediction for the width difference $\Delta {\Gamma }_s$ matching the precise experimental data. We present compact analytic results for all matching coefficients in an expansion in $m_c/m_b$ up to second order. Our new corrections are comparable in size to the current experimental error and slightly increase $\Delta {\Gamma }_s$.

    hep-phhep-exhep-lathep-thJHEP(2021)·26 citations
22. 22*

    Masses and decay constants of the $\eta$ and ${\eta }^{\prime }$ mesons from lattice QCD

    Gunnar S. Bali🇩🇪 · Vladimir Braun🇩🇪 · Sara Collins🇩🇪 · Andreas Schäfer🇩🇪 · Jakob Simeth🇩🇪

    We determine the masses, the singlet and octet decay constants as well as the anomalous matrix elements of the $\eta$ and ${\eta }^{\prime }$ mesons in $N_f=2+1$ QCD\@. The results are obtained using twenty-one CLS ensembles of non-perturbatively improved Wilson fermions that span four lattice spacings ranging from $a\approx 0.086$fm down to $a\approx 0.050$fm. The pion masses vary from $M_{\pi }=420$MeV to $126$MeV and the spatial lattice extents $L_s$ are such that $L_s{M}_{\pi }\gtrsim 4$, avoiding significant finite volume effects. The quark mass dependence of the data is tightly constrained by employing two trajectories in the quark mass plane, enabling a thorough investigation of U($3$) large-$N_c$ chiral perturbation theory (ChPT). The continuum limit extrapolated data turn out to be reasonably well described by the next-to-leading order ChPT parametrization and the respective low energy constants are determined. The data are shown to be consistent with the singlet axial Ward identity and, for the first time, also the matrix elements with the topological charge density are computed. We also derive the corresponding next-to-leading order large-$N_c$ ChPT formulae. We find $F^8=115.0(2.8)\text{MeV}$, ${\theta }_8=-25.8(2.3{)}^{\circ }$, ${\theta }_0=-8.1(1.8{)}^{\circ }$ and, in the $\overline{\mathrm{MS}}$ scheme for $N_f=3$, $F^0(\mu =2\mathrm{GeV})=100.1(3.0)\text{MeV}$, where the decay constants read $F_{\eta }^8=F^8\cos {\theta }_8$, $F_{{\eta }^{\prime }}^8=F^8\sin {\theta }_8$, $F_{\eta }^0=-F^0\sin {\theta }_0$ and $F_{{\eta }^{\prime }}^0=F^0\cos {\theta }_0$. For the gluonic matrix elements, we obtain $a_{\eta }(\mu =2\mathrm{GeV})=0.0170(10){\mathrm{GeV}}^3$ and $a_{{\eta }^{\prime }}(\mu =2\mathrm{GeV})=0.0381(84){\mathrm{GeV}}^3$, where statistical and all systematic errors are added in quadrature.

    ↳ hep-lathep-phJHEP(2021)·94 citations
23. 23*

    Does the Reionization Model Influence the Constraints on Dark Matter Decay or Annihilation?

    Lu Chen🇨🇳 · Ke Wang🇨🇳

    If dark matter decay or annihilate, a large amount of energy and particles would be released into the cosmic plasma. Therefore, they could modify the thermal and ionization history of our universe, then leave footprints on the cosmic microwave background power spectra. In this paper, we take dark matter annihilation as an example and investigate whether different reionization models influence the constraints on dark matter annihilation. We consider the ionization history including both dark matter annihilation and star formation, then put constraints on DM annihilation. Combining the latest Planck data, BAO data, SNIa measurement, $Q_{\text{HII}}$ constraints from observations of quasars, as well as the star formation rate density from UV and IR data, the optical depth is $\tau =0.0571_{-0.0006}^{+0.0005}$ at 68$\%$C.L. and the upper limit of ${ϵ}_0{f}_d$ reads $2.7765\times 10^{-24}$ at 95$\%$C.L.. By comparison, we also constrain dark matter annihilation in the instantaneous reionization model from the same data combination except the $Q_{\text{HII}}$ constraints and star formation rate density. We get $\tau =0.0559_{-0.0076}^{+0.0069}$ at 68$\%$C.L. and the upper limit of ${ϵ}_0{f}_d$ is $2.8468\times 10^{-24}$ at 95$\%$C.L.. %, which is $2.5\%$ higher than the results in the previous model. This indicates various reionization models have little influence ($\lesssim 2.5\%$) on constraining parameters of dark matter decay or annihilation.

    ↳ astro-ph.COhep-phJCAP(2021)·2 citations
24. 24*

    Universal $10^{20}$Hz stochastic gravitational waves from photon spheres of black holes

    Kaishu Saito🇯🇵 · Jiro Soda🇯🇵 · Hirotaka Yoshino🇯🇵

    We show that photon spheres of supermassive black holes generate high-frequency stochastic gravitational waves through the photon-graviton conversion. Remarkably, the frequency is universally determined as $m_e\sqrt{m_e/m_p}\simeq 10^{20}\text{Hz}$ in terms of the proton mass $m_p$ and the electron mass $m_e$. It turns out that the density parameter of the stochastic gravitational waves ${\Omega }_{\text{gw}}$ could be $10^{-12}$. Since the existence of the gravitational waves from photon spheres is robust, it is worth seeking methods of detecting high-frequency gravitational waves around $10^{20}$Hz.

    ↳ gr-qcastro-ph.HEhep-phPRD(2021)·11 citations
25. 25*

    Interactions of two and three mesons including higher partial waves from lattice QCD

    Tyler D. Blanton🇺🇸 · Andrew D. Hanlon🇩🇪 · Ben Hörz🇺🇸 · Colin Morningstar🇺🇸 · Fernando Romero-López🇪🇸 · Stephen R. Sharpe🇺🇸

    We study two- and three-meson systems composed either of pions or kaons at maximal isospin using Monte Carlo simulations of lattice QCD. Utilizing the stochastic LapH method, we are able to determine hundreds of two- and three-particle energy levels, in nine different momentum frames, with high precision. We fit these levels using the relativistic finite-volume formalism based on a generic effective field theory in order to determine the parameters of the two- and three-particle K-matrices. We find that the statistical precision of our spectra is sufficient to probe not only the dominant $s$-wave interactions, but also those in $d$ waves. In particular, we determine for the first time a term in the three-particle K-matrix that contains two-particle $d$ waves. We use three $N_f=2+1$ CLS ensembles with pion masses of $200$, $280$, and $340$MeV. This allows us to study the chiral dependence of the scattering observables, and compare to the expectations of chiral perturbation theory.

    ↳ hep-lathep-phnucl-thJHEP(2021)·72 citations
26. 26*

    Primordial black hole production during first-order phase transitions

    Jing Liu🇨🇳 · Ligong Bian🇨🇳 · Rong-Gen Cai🇨🇳 · Zong-Kuan Guo🇨🇳 · Shao-Jiang Wang🇨🇳

    Primordial black holes (PBHs) produced in the early Universe have attracted wide interest for their ability to constitute dark matter and explain the compact binary coalescence. We propose a new mechanism of PBH production during first-order phase transitions (PTs) and find that PBHs are naturally produced during PTs model-independently. Because of the randomness of the quantum tunneling, there always exists some probability that the vacuum decay is postponed in a whole Hubble volume. Since the vacuum energy density remains constant while radiation is quickly redshifted in the expanding Universe, the postponed vacuum decay then results in overdense regions, which finally collapse into PBHs as indicated by numerical simulations. Utilizing this result one can obtain mutual predictions and constraints between PBHs and GWs from PTs. The predicted mass function of PBHs is nearly monochromatic. We investigate two typical cases and find that 1) PBHs from a PT constitute all dark matter and GWs peak at $1$Hz, 2) PBHs from a PT can explain the coalescence events observed by LIGO-Virgo collaboration, and meanwhile GWs can explain the common-spectrum process detected by NANOGrav collaboration.

    ↳ astro-ph.COgr-qchep-phPRD(2022)·204 citations
27. 27*

    Direct observation of the dead-cone effect in QCD

    ALICE Collaboration

    In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). These partons subsequently emit further partons in a process that can be described as a parton shower which culminates in the formation of detectable hadrons. Studying the pattern of the parton shower is one of the key experimental tools for testing QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass $m_{\mathrm{Q}}$ and energy $E$, within a cone of angular size $m_{\mathrm{Q}}$/$E$ around the emitter. Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics.

    ↳ nucl-exhep-exhep-phNature(2022)·189 citations
28. 28*

    Field excitation in fuzzy dark matter near a strong gravitational wave source

    Shreyansh S. Dave🇮🇳 · Sanatan Digal🇮🇳

    The axion-like particles with ultralight mass ($\sim 10^{-22}$eV) can be a possible candidate of dark matter, known as the fuzzy dark matter (FDM). These particles form Bose-Einstein condensate in the early Universe which can explain the dark matter density distribution in galaxies at the present time. We study the time evolution of ultralight axion-like field in the near region of a strong gravitational wave (GW) source, such as binary black hole merger. We show that GWs can lead to the generation of field excitations in a spherical shell about the source that eventually propagate out of the shell to minimize the energy density of the field configuration. These excitations are generated toward the end of the merger and in some cases even in the ringdown phase of the merger, therefore it can provide a qualitatively distinct prediction for changes in the GW waveform due to the presence of FDM. This would be helpful in investigating the existence of FDM in galaxies.

    ↳ gr-qcastro-ph.HEhep-phhep-th+1PRD(2022)·6 citations
29. 29*

    Causality and gravity

    John F. Donoghue🇺🇸 · Gabriel Menezes🇧🇷

    We show how uncertainty in the causal structure of field theory is essentially inevitable when one includes quantum gravity. This includes the fact that lightcones are ill-defined in such a theory. This effect is small in the effective field theory regime, where it it independent of the UV completion of the theory, but grows with energy and represents an unknown uncertainty for a generic UV completion. We include details of the causality uncertainty which arises in a particular UV completion, i.e. quadratic gravity. We describe how the mechanisms uncovered in the effective field theory treatment, and some of those in quadratic gravity, could be common features of quantum gravity.

    ↳ hep-thgr-qchep-phJHEP(2021)·16 citations
30. 30*

    Observational prospects for phase transitions at LISA: Fisher matrix analysis

    Chloe Gowling🇬🇧 · Mark Hindmarsh🇬🇧

    A first order phase transition at the electroweak scale would lead to the production of gravitational waves that may be observable at upcoming space-based gravitational wave (GW) detectors such as LISA (Laser Interferometer Space Antenna). As the Standard Model has no phase transition, LISA can be used to search for new physics by searching for a stochastic gravitational wave background. In this work we investigate LISA's sensitivity to the thermodynamic parameters encoded in the stochastic background produced by a phase transition, using the sound shell model to characterise the gravitational wave power spectrum, and the Fisher matrix to estimate uncertainties. We explore a parameter space with transition strengths $\alpha <0.5$ and phase boundary speeds $0.4<v_{\text{w}}<0.9$, for transitions nucleating at $T_{\text{N}}=100$ GeV, with mean bubble spacings $0.1$ and $0.01$ of the Hubble length, and sound speed $c/\sqrt{3}$. We show that the power spectrum in the sound shell model can be well approximated by a four-parameter double broken power law, and find that the peak power and frequency can be measured to approximately 10% accuracy for signal-to-noise ratios (SNRs) above 20. Determinations of the underlying thermodynamic parameters are complicated by degeneracies, but in all cases the phase boundary speed will be the best constrained parameter. Turning to the principal components of the Fisher matrix, a signal-to-noise ratio above 20 produces a relative uncertainty less than 3% in the two highest-order principal components, indicating good prospects for combinations of parameters. The highest-order principal component is dominated by the wall speed. These estimates of parameter sensitivity provide a preliminary accuracy target for theoretical calculations of thermodynamic parameters.

    ↳ astro-ph.COgr-qchep-phJCAP(2021)·94 citations
31. 31*

    Confinement and Renormalization Group Equations in String-inspired Non-local Gauge Theories

    Marco Frasca🇮🇹 · Anish Ghoshal🇵🇱 · Nobuchika Okada🇺🇸

    As an extension of the weak perturbation theory obtained in recent analysis on infinite-derivative non-local non-Abelian gauge theories motivated from p-adic string field theory, and postulated as direction of UV-completion in 4-D Quantum Field Theory (QFT), here we investigate the confinement conditions and $\beta -$function in the strong coupling regime. We extend the confinement criterion, previously obtained by Kugo and Ojima for the local theory based on the Becchi-Rouet-Stora-Tyutin (BRST) invariance, to the non-local theory, by using a set of exact solutions of the corresponding local theory. We show that the infinite-derivatives which are active in the UV provides finite contributions also in the infrared (IR) limit and provide a proof of confinement, granted by the absence of the Landau pole. The main difference with the local case is that the IR fixed point is moved to infinity. We also show that in the limit of the energy scale of non-locality $M\to \infty$ we reproduce the local theory results and see how asymptotic freedom is properly recovered.

    ↳ hep-thgr-qchep-phPRD(2021)·21 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.