HEP Phenomenology·hep-ph

Tue·Jun 4, 2019Tuesday·June 4, 2019

39 papers—19 primary·20 cross-listed·reconstructed*

01*
Improved Gauss law model and in-medium heavy quarkonium at finite density and velocity
David Lafferty🇩🇪 · Alexander Rothkopf🇳🇴
We explore the in-medium properties of heavy-quarkonium states at finite baryo-chemical potential and finite transverse momentum based on a modern complex-valued potential model. Our starting point is a novel, rigorous derivation of the generalized Gauss law for in-medium quarkonium, combining the non-perturbative physics of the vacuum bound state with a weak coupling description of the medium degrees of freedom. Its relation to previous models in the literature is discussed. We show that our approach is able to reproduce the complex lattice QCD heavy quark potential even in the non-perturbative regime, using a single temperature dependent parameter, the Debye mass $m_{D}$ . After vetting the Gauss-law potential with state-of-the-art lattice QCD data, we extend it to the regime of finite baryon density and finite velocity, currently inaccessible to first principles simulations. In-medium spectral functions computed from the Gauss-law potential are subsequently used to estimate the $ψ^{'} / J / ψ$ ratio in heavy-ion collisions at different beam energies and transverse momenta. We find qualitative agreement with the predictions from the statistical model of hadronization for the $s_{N N}$ dependence and a mild dependence on the transverse momentum.
hep-phhep-latnucl-thPRD(2020)·82 citations
02*
The CPT-violating effects on neutrons' gravitational bound state
Zhi Xiao🇨🇳 · Lijing Shao🇨🇳
In this work, the CPT-violating (CPTV) interactions on neutrons' gravitational bound state are studied. With simple analytical solutions, we provide a preliminary investigation on the Lorentz-violation (LV) induced spin precession due to the $σ \cdot b ~ (1 + g z)$ and $b ˉ / m_{_{I}} σ \cdot p^$ couplings, where $b ~$ and $b ˉ$ represent LV coefficients. The helicity-dependent couplings can induce unusual phase evolutions with position and momentum dependence. As $b ~$ varies with time due to the Earth's motion, the spin polarization also shows a sidereal time dependence, and it may be enhanced with time for ultra-stable polarized state of neutrons. The inseparability of the spin-momentum coupling of the $b ˉ$ -term can also lead to motional dependent polarization state. With the precisely measured transition frequency between different gravitational bound states, we get a rough bound $∣ b ~ ∣ < 3.9 \times 1 0^{- 3}$ GeV for unpolarized neutrons. If the spin-flip transition frequency can reach comparable precision in the future, the bound can be improved to the level of $1 0^{- 24}$ GeV. The test of weak equivalence principle with polarized atom may also improve it significantly.
hep-phJ.Phys.G(2020)·6 citations
03*
Discussions on the Line-shape of $X (4660)$ Resonance
Qin-Fang Cao🇨🇳 · Hong-Rong Qi🇨🇳 · Yu-Fei Wang🇨🇳 · Han-Qing Zheng🇨🇳
A careful reanalysis is made on $e^{+} e^{-} \to X (4660) \to (Λ_{c} Λ ˉ_{c}) / (ψ^{'} π π)$ processes, aiming at resolving the apparent conflicts between Belle and BESIII data above $Λ_{c} Λ ˉ_{c}$ threshold. We use a model containing a Breit-Wigner resonance and $Λ_{c} Λ ˉ_{c}$ four-point contact interactions, with which the enhancement right above the $Λ_{c} Λ ˉ_{c}$ threshold is well explained by a virtual pole generated by $Λ_{c} Λ ˉ_{c}$ attractive final state interaction, located at $M_{V} = 4.566 \pm 0.007$ GeV. Meanwhile, $X (4660)$ remains to be a typical Breit-Wigner resonance, and is hence of confinement nature. Our analysis strongly suggests the existence of the virtual pole with statistical significance of $4.2$ standard deviation ( $σ$ ). Nevertheless, the conclusion crucially depends on the line-shape of cross sections which are of limited statistics, hence we urge new experimental analyses from Belle II, BESIII, and LHCb to settle the issue.
hep-phnucl-thPRD(2019)·32 citations
04*
Flavor hierarchy of jet quenching in relativistic heavy-ion collisions
Wen-Jing Xing🇨🇳 · Shanshan Cao🇺🇸 · Guang-You Qin🇨🇳 · Hongxi Xing
Relativistic heavy-ion experiments have observed similar quenching effects for (prompt) $D$ mesons compared to charged hadrons for transverse momenta larger than 6-8~GeV, which remains a mystery since heavy quarks typically lose less energies in quark-gluon plasma than light quarks and gluons. Recent measurements of the nuclear modification factors of $B$ mesons and $B$ -decayed $D$ mesons by the CMS Collaboration provide a unique opportunity to study the flavor hierarchy of jet quenching. Using a linear Boltzmann transport model combined with hydrodynamics simulation, we study the energy loss and nuclear modification for heavy and light flavor jets in high-energy nuclear collisions. By consistently taking into account both quark and gluon contributions to light and heavy flavor hadron productions within a next-to-leading order perturbative QCD framework, we obtain, for the first time, a satisfactory description of the experimental data on the nuclear modification factors for charged hadrons, $D$ mesons, $B$ mesons and $B$ -decayed $D$ mesons simultaneously over a wide range of transverse momenta (8-300~GeV). This presents a solid solution to the flavor puzzle of jet quenching and constitutes a significant step towards the precision study of jet-medium interaction. Our study predicts that at transverse momenta larger than 30-40~GeV, $B$ mesons also exhibit similar suppression effects to charged hadrons and $D$ mesons, which may be tested by future measurements.
hep-phnucl-exnucl-thPLB(2020)·62 citations
05*
Finite size effects in the free energy density for Abelian (anti-)self-dual gluon field in $S U (3)$ gluodynamics
Sergei N. Nedelko🇷🇺 · Vladimir E. Voronin🇷🇺
Finite-size effects in the free energy density for Abelian (anti-)self-dual gluon field are investigated within $S U (3)$ gluodynamics. In particular, the role of gluon quasi-zero modes is studied. The effective potential is calculated within the framework of zeta function regularization for finite spherical four-dimensional region of radius $R$ in Euclidean space-time. In order to obtain the correct strong-field behavior of the effective potential which is determined by the asymptotic freedom, the quasi-zero gluon modes have to be treated beyond one-loop approximation in line with the argumentaion of Leutwyler. Conditions for appearance of the global minimum of the free energy density at finite nonzero values of both field strength and region size are discussed.
hep-phPhys.Part.Nucl.Lett.(2019)·2 citations
06*
Reinforcement of $K_{S}^{0}$ regeneration in the model with Hermitian Hamiltonian
V.I. Nazaruk🇷🇺
The simple model of the $K_{S}^{0}$ regeneration with the Hermitian Hamiltonian is proposed. The increase of regeneration takes place.
hep-ph1 citation
07*
Vorticity, kinetic energy, and suppressed gravitational wave production in strong first order phase transitions
Daniel Cutting🇬🇧 · Mark Hindmarsh🇬🇧 · David J. Weir🇫🇮
We have performed the first 3-dimensional simulations of strong first-order thermal phase transitions in the early Universe. For deflagrations, we find that the rotational component of the fluid velocity increases as the transition strength is increased. For detonations, however, the rotational velocity component remains constant and small. We also find that the efficiency with which kinetic energy is transferred to the fluid falls below theoretical expectations as we increase the transition strength. The probable origin of the kinetic energy deficit is the formation of reheated droplets of the metastable phase during the collision, slowing the bubble walls. The rate of increase in the gravitational wave energy density for deflagrations in strong transitions is suppressed compared to that predicted in earlier work. This is largely accounted for by the reduction in kinetic energy. Current modelling therefore substantially overestimates the gravitational wave signal for strong transitions with deflagrations, in the most extreme case by a factor of $1 0^{3}$ . Detonations are less affected.
hep-phastro-ph.COPRL(2020)·239 citations
08*
Possible s-wave annihilation for MeV dark matter with the 21-cm absorption
Lian-Bao Jia🇨🇳 · Xu Liao🇨🇳
The CMB observation sets stringent constraints on MeV dark matter (DM) annihilating into charged states/photons in s-wave, and the recent observation of the 21-cm absorption at the cosmic dawn reported by EDGES is also very strict for s-wave annihilations of MeV DM. The millicharged DM with p-wave dominant annihilations during the freeze-out period are considered in literatures to give an explanation about the 21-cm absorption, with photon mediated scattering cooling the hydrogen. In this paper, we focus on the annihilation of millicharged DM being s-wave dominant. To explain the 21-cm absorption and meanwhile be compatible with the CMB and 21-cm absorption bounds on DM annihilations, we consider the annihilation close to the resonance, with the new mediator (here is dark photon) mass being slightly above twice of the millicharged DM mass. In this case, the annihilation cross section at the temperature $T \to 0$ could be much smaller than that at $T_{f}$ , which would be tolerated by the bounds on DM annihilations, avoiding the excess heating from DM s-wave annihilations to the hydrogen gas. The beam dump and lepton collider experiments can be employed to hunt for millicharged DM via the production of the invisible dark photon.
hep-phastro-ph.COPRD(2019)·5 citations
09*
Electron EDM and Muon anomalous magnetic moment in Two-Higgs-Doublet Models
Eung Jin Chun🇰🇷 · Jongkuk Kim🇰🇷 · Tanmoy Mondal🇰🇷
The CP violating two-Higgs doublet model of type-X may enhance significantly the electric and magnetic moment of leptons through two-loop Barr-Zee diagrams. We analyze the general parameter space of the type-X 2HDM consistent with the muon $g - 2$ and the electron EDM measurements to show how strongly the CP violating parameter is constrained in the region explaining the muon $g - 2$ anomaly.
hep-phhep-exJHEP(2019)·50 citations
10*
Constraints on ultra-light axions from compact binary systems
Tanmay Kumar Poddar🇮🇳 · Subhendra Mohanty🇮🇳 · Soumya Jana🇮🇳
Ultra light particles $(m_{a} \sim 1 0^{- 21} e V - 1 0^{- 22} e V)$ with axion-like couplings to other particles can be candidates for fuzzy dark matter (FDM) if the axion decay constant $f_{a} \sim 1 0^{17} G e V$ . If a compact star is immersed in such a low mass axionic potential it develops a long range field outside the star. This axionic field is radiated away when the star is in a binary orbit. The orbital period of a compact binary decays mainly due to the gravitational wave radiation, which was confirmed first in the Hulse-Taylor binary pulsar. The orbital period can also decay by radiation of other light particles like axions and axion like particles(ALPs). For axionic radiation to take place, the orbital frequency of the periodic motion of the binary system should be greater than the mass of the scalar particle which can be radiated. This implies that, for most of the observed binaries, particles with mass $m_{a} < 1 0^{- 19} e V$ can be radiated, which includes FDM particles. In this paper, we consider four compact binary systems: PSR J0348+0432, PSR J0737-3039, PSR J1738+0333, and PSR B1913+16 (Hulse Taylor Binary) and show that the observations of the decay in orbital period put the bound on axion decay constant, $f_{a} ≲ O (1 0^{11} G e V)$ . This implies that Fuzzy Dark Matter cannot couple to gluons.
hep-phastro-ph.COgr-qcPRD(2020)·63 citations
11*
New parametrization of the form factors in $B ˉ \to D ℓ ν ˉ_{ℓ}$ decays
De-Liang Yao🇨🇳 · Pedro Fernandez-Soler🇪🇸 · Feng-Kun Guo🇨🇳 · Juan Nieves🇪🇸
A new model-independent parametrization is proposed for the hadronic form factors in the semileptonic $B ˉ \to D ℓ ν ˉ_{ℓ}$ decay. By a combined consideration of the recent experimental and lattice QCD data, we determine precisely the Cabibbo-Kobayashi-Maskawa matrix element $∣ V_{c b} ∣ = 41.01 (75) \times 1 0^{- 3}$ and the ratio $R_{D} = \frac{B R ( B ˉ \to D τ ν ˉ _{τ} )}{B R ( B ˉ \to D ℓ ν ˉ _{ℓ} )} = 0.301 (5)$ . The coefficients in this parametrization, related to phase shifts by sumrulelike dispersion relations and hence called phase moments, encode important scattering information of the $B ˉ D ˉ$ interactions which are poorly known so far. Thus, we give strong hints about the existence of at least one bound and one virtual $B ˉ D ˉ$ $S$ -wave $0^{+}$ states, subject to uncertainties produced by potentially sizable inelastic effects. This formalism is also applicable for any other semileptonic processes induced by the weak $b \to c$ transition.
hep-phhep-exhep-latPRD(2020)·15 citations
12*
Using bottomonium production as a tomographic probe of the quark-gluon plasma
Michael Strickland🇺🇸
The suppression of bottomonia in ultrarelativistic heavy-ion collisions is a smoking gun for the production of a strongly interacting final state in ultrarelativistic heavy-ion collisions. Furthermore, these final state interactions are consistent with the production of a hot hydrodynamically expanding quark-gluon plasma with initial temperatures on the order of 600-700 MeV at LHC collision energies. Models which incorporate plasma screening and bound-state breakup based on high-temperature quantum chromodynamics are in good agreement with the centrality, transverse-momentum, and rapidity dependence of the suppression seen in the highest energy LHC Pb-Pb collisions. The models of heavy-quark bound state breakup/formation are coupled to the soft dynamics of the quark-gluon plasma using 3+1d relativistic anisotropic hydrodynamics. At later times, excited state feed-down is taken into account using independently constrained excited state feed down fractions. Comparisons with LHC experimental data are consistent with primordial suppression of all bottomonium states, with states having the lowest binding energies being the ones which suffer the most suppression. In this proceedings contribution, I will review recent work to (a) include the effects of regeneration on bottomonium production and (b) to assess the effects of a rapidly changing in-medium potential on bottomonium production in the quark-gluon plasma.
hep-phnucl-thPoS(2020)·4 citations
13*
Near threshold $J / ψ$ and $Υ$ photo-production at JLab and RHIC
Yoshitaka Hatta🇺🇸 · Abha Rajan🇺🇸 · Di-Lun Yang🇯🇵
We update our previous calculation of $J / ψ$ photo-production near threshold \cite{Hatta:2018ina} by incorporating the recent developments in theory and the new experimental data from the GlueX collaboration at Jefferson Lab \cite{Ali:2019lzf}. We then propose to study the near threshold production of $Υ$ and $J / ψ$ in ultraperipheral $p A$ collisions at RHIC. These processes are sensitive to the gluon condensate in the proton which is related to the QCD trace anomaly. Our result emphasizes the role of gluons as the origin of the proton mass.
hep-phPRD(2019)·74 citations
14*
Production of Z-bosons in the parton branching method
A. Bermudez Martinez🇩🇪 · P. Connor🇩🇪 · D. Dominguez Damiani🇩🇪 · L.I. Estevez Banos🇩🇪 · F. Hautmann🇧🇪 · H. Jung🇩🇪 · J. Lidrych🇩🇪 · M. Schmitz🇩🇪 · S. Taheri Monfared🇩🇪 · Q. Wang🇩🇪 · R. Zlebcik🇩🇪
Transverse Momentum Dependent (TMD) parton distributions obtained from the Parton Branching (PB) method are combined with next-to-leading-order (NLO) calculations of Drell-Yan (DY) production. We apply the MCatNLO method for the hard process calculation and matching with the PB TMDs. We compute predictions for the transverse momentum, rapidity and $ϕ^{*}$ spectra of Z-bosons. We find that the theoretical uncertainties of the predictions are dominated by the renormalization and factorization scale dependence, while the impact of TMD uncertainties is moderate. The theoretical predictions agree well, within uncertainties, with measurements at the Large Hadron Collider (LHC). In particular, we study the region of lowest transverse momenta at the LHC, and comment on its sensitivity to nonperturbative TMD contributions.
hep-phPRD(2019)·108 citations
15*
Very Light Asymmetric Dark Matter
Gonzalo Alonso-Álvarez🇩🇪 · Julia Gehrlein🇪🇸 · Joerg Jaeckel🇩🇪 · Sebastian Schenk🇩🇪
Very light dark matter is usually taken to consist of uncharged bosons such as axion-like particles or dark photons. Here, we consider the prospect of very light, possibly even sub-eV dark matter carrying a net charge that is (approximately) conserved. By making use of the Affleck-Dine mechanism for its production, we show that a sizable fraction of the energy density can be stored in the asymmetric component. We furthermore argue that there exist regions of parameter space where the energy density contained in symmetric particle-antiparticle pairs without net charge can to some degree be depleted by considering couplings to additional fields. Finally, we make an initial foray into the phenomenology of this scenario by considering the possibility that dark matter is coupled to the visible sector via the Higgs portal.
hep-phastro-ph.COJCAP(2019)·15 citations
16*
Low scale type I seesaw model for lepton masses and mixings
A. E. Cárcamo Hernández🇨🇱 · Marcela González🇨🇱 · Nicolás A. Neill🇨🇱
In contrast to the original type I seesaw mechanism that requires right-handed Majorana neutrinos at energies much higher than the electroweak scale, the so-called low scale seesaw models allow lighter masses for the additional neutrinos. Here we propose an alternative low scale type I seesaw model, where neither linear nor inverse seesaw mechanisms take place, but the spontaneous breaking of a discrete symmetry at an energy scale much lower than the model cutoff is responsible for the smallness of the light active neutrino masses. In this scenario, the model is defined with minimal particle content, where the right-handed Majorana neutrinos can have masses at the $\sim 50 \mbox G e V$ scale. The model is predictive in the neutrino sector having only four effective parameters that allow to successfully reproduce the experimental values of the six low energy neutrino observables.
hep-phPRD(2020)·17 citations
17*
Super heavy thermal dark matter
Hyungjin Kim🇮🇱 · Eric Kuflik🇮🇱
We propose a mechanism of elementary thermal dark matter with mass up to $1 0^{14}$ GeV, within a standard cosmological history, whose relic abundance is determined solely by its interactions with the Standard Model, without violating the perturbative unitarity bound. The dark matter consists of many nearly degenerate particles which scatter with the Standard Model bath in a nearest-neighbor chain, and maintain chemical equilibrium with the Standard Model bath by in-equilibrium decays and inverse decays. The phenomenology includes super heavy elementary dark matter and heavy relics that decay at various epochs in the cosmological history, with implications for CMB, structure formation and cosmic ray experiments.
hep-phastro-ph.COPRL(2019)·65 citations
18*
Top quark mass dependence of the Higgs-gluon form factor at three loops
Joshua Davies🇩🇪 · Ramona Groeber🇩🇪 · Andreas Maier🇩🇪 · Thomas Rauh🇨🇭 · Matthias Steinhauser🇩🇪
We compute three-loop corrections to the Higgs-gluon form factor, incorporating the top quark mass dependence. Our method is based on the combination of expansions around the top threshold and for large top quark mass, using conformal mapping and Padé approximation to describe the form factor over the full kinematic range.
hep-phPRD(2019)·36 citations
19*
Anatomy of $B_{s} \to P P$ decays and effects of the next-to-leading order contributions in the perturbative QCD approach
Da-Cheng Yan🇨🇳 · Xin Liu🇨🇳 · Zhen-Jun Xiao🇨🇳
By employing the perturbative QCD (PQCD) factorization approach, we made a systematic investigation for the CP-averaged branching ratios and the CP-violating asymmetries of the thirteen $B ˉ_{s}^{0} \to P P$ decays ( here $P = (π, K, η, η^{'})$ ) with the inclusion of all currently known next-to-leading order (NLO) contributions, and compared our results with the measured values or the theoretical predictions from other different approaches. We focused on the examination of the effects of the NLO contributions and found the following points: (a) for $B ˉ_{s}^{0} \to (K^{0} K ˉ^{0}, K^{+} K^{-}, η^{'} η^{'}, π^{-} K^{+})$ decays, the NLO contributions can provide a $(40 - 150) %$ enhancement or a $20%$ reduction to the corresponding leading order (LO) PQCD predictions for their decay rates and result in a much better agreement between the PQCD predictions and the experimental measurements; (b) for the pure annihilation decay $B ˉ_{s}^{0} \to π^{+} π^{-}$ , the PQCD prediction still remain consistent with the data after the inclusion of the small NLO reduction; (c) the PQCD predictions for the ratio $(f_{s} / f_{d}) \cdot B (B_{s}^{0} \to π^{+} π^{-}) / B (B^{0} \to K^{+} π^{-})$ and $(f_{s} / f_{d}) \cdot B (B_{s}^{0} \to π^{+} K^{-}) / B (B^{0} \to K^{+} π^{-})$ become agree very well with the measured ones after the inclusion of a $40%$ NLO reduction; (d) for $B ˉ_{s}^{0} \to K^{+} K^{-}$ and $B ˉ_{s}^{0} \to π^{-} K^{+}$ decays, the NLO PQCD predictions for their CP-violating asymmetries do agree very well with the measured values in both the sign and the magnitude; and (e) for all $B ˉ_{s}^{0} \to P P$ decays, we also compared our results with those obtained in the QCD factorization approach and soft-collinear effective theory and discussed their similarities and differences.
hep-phhep-exNPB(2019)·4 citations
20*
Where Are We With Light Sterile Neutrinos?
A. Diaz🇺🇸 · C.A. Argüelles🇺🇸 · G.H. Collin🇺🇸 · J.M. Conrad🇺🇸 · M.H. Shaevitz🇺🇸
We review the status of searches for sterile neutrinos in the $\sim 1$ eV range, with an emphasis on the latest results from short baseline oscillation experiments and how they fit within sterile neutrino oscillation models. We present global fit results to a three-active-flavor plus one-sterile-flavor model (3+1), where we find an improvement of $Δ χ^{2} = 35$ for 3 additional parameters compared to a model with no sterile neutrino. This is a 5 $σ$ improvement, indicating that an effect that is like that of a sterile neutrino is highly preferred by the data. However we note that separate fits to the appearance and disappearance oscillation data sets within a 3+1 model do not show the expected overlapping allowed regions in parameter space. This "tension" leads us to explore two options: 3+2, where a second additional mass state is introduced, and a 3+1+decay model, where the $ν_{4}$ state can decay to invisible particles. The 3+1+decay model, which is also motivated by improving compatibility with cosmological observations, yields the larger improvement, with a $Δ χ^{2} = 8$ for 1 additional parameter beyond the 3+1 model, which is a $2.6 σ$ improvement. Moreover the tension between appearance and disappearance experiments is reduced compared to 3+1, although disagreement remains. In these studies, we use a frequentist approach and also a Bayesean method of finding credible regions. With respect to this tension, we review possible problems with the global fitting method. We note multiple issues, including problems with reproducing the experimental results, especially in the case of experiments that do not provide adequate data releases. We discuss an unexpected 5 MeV excess, observed in the reactor flux energy spectrum, that may be affecting the oscillation interpretation of the short baseline reactor data. We emphasize the care that must be taken in mapping to the true neutrino energy in the case of oscillation experiments that are subject to multiple interaction modes and nuclear effects. We point to problems with the "Parameter-Goodness-of-Fit test" that is used to quantify the tension. Lastly, we point out that analyses presenting limits often receive less scrutiny that signals. While we provide a snapshot of the status of sterile neutrino searches today and global fits to their interpretation, we emphasize that this is a fast-moving field. We briefly review experiments that are expected to report new data in the immediate future. Lastly, we consider the 5-year horizon, where we propose that decay-at-rest neutrino sources are the best method of finally resolving the confusing situation.
↳ hep-exhep-phPhys.Rept.(2020)·270 citations
21*
Dynamics near a first order phase transition
Loredana Bellantuono🇮🇹 · Romuald A. Janik🇵🇱 · Jakub Jankowski🇵🇱 · Hesam Soltanpanahi🇨🇳
We study various dynamical aspects of systems possessing a first order phase transition in their phase diagram. We isolate three qualitatively distinct types of theories depending on the structure of instabilities and the nature of the low temperature phase. The non-equilibrium dynamics is modeled by a dual gravitational theory in 3+1 dimension which is coupled to massive scalar field with self interacting potential. By numerically solving the Einstein-matter equations of motion with various initial configurations, we investigate the structure of the final state arising through coalescence of phase domains. We find that static phase domains, even quite narrow are very long lived and we find a phenomenological equation for their lifetime. Within our framework we also analyze moving phase domains and their collision as well as the effects of spinodal instability and dynamical instability on an expanding boost invariant plasma.
↳ hep-thgr-qchep-phJHEP(2019)·36 citations
22*
The structure of cold neutron star with a quark core within the MIT and NJL models
T. Yazdizadeh🇮🇷 · G. H. Bordbar🇮🇷
Neutron star due to their high interior matter density are expected to be composed of a quark core, a mixed quark-hadron matter, and a layer of hadronic matter. Thus, in this paper, we compute the equation of state of these parts of neutron star to evaluate its structure properties. We use two models for describing EOS of quark matter, NJL and MIT bag models, and employ three approaches in this work. A density dependent bag constant satisfy the quark confinement in the simple MIT bag model. We also study the interaction behavior of quarks, firstly one gluon exchange within MIT bag model and the secondly dynamical mass will be held as effective interaction that roles between particles. Density dependence of quark mass is obtained from NJL self consistent model. NJL model is a effective manner for justify the chiral symmetry. Applying the Gibbs conditions the equation of state of the quarks and hadrons mixed phase is obtained. Since the hadronic matter is under the influence of strong force of nucleons, we calculate the equation of state of this phase using a powerful variational many-body technique. Finally, we calculate the mass and radius of a cold neutron star with a quark core by numerically solving the TOV equation. To check our used EOS, we compare our results with the recent observational data. Our results are in a good agreement with some observed compact objects such as $S A X J 1748.9 - 2021$ , $4 U 1608 - 52$ and $V e l a X - 1$ .
↳ nucl-thastro-ph.HEhep-phIran.J.Sci.Technol.A(2019)·8 citations
23*
Dark matter search in missing energy events with NA64
D. Banerjee🇨🇭 · V.E. Burtsev🇷🇺 · A.G. Chumakov🇷🇺 · D. Cooke🇨🇭 · P. Crivelli🇨🇭 · E. Depero🇨🇭 · A.V. Dermenev🇷🇺 · S.V. Donskov🇷🇺 · R.R. Dusaev🇷🇺 · T. Enik🇷🇺 · N. Charitonidis🇨🇭 · A. Feshchenko🇷🇺 and 39 other authors
A search for sub-GeV dark matter production mediated by a new vector boson $A^{'}$ , called dark photon, is performed by the NA64 experiment in missing energy events from 100 GeV electron interactions in an active beam dump at the CERN SPS. From the analysis of the data collected in the years 2016, 2017, and 2018 with $2.84 \times 1 0^{11}$ electrons on target no evidence of such a process has been found. The most stringent constraints on the $A^{'}$ mixing strength with photons and the parameter space for the scalar and fermionic dark matter in the mass range $≲ 0.2$ GeV are derived, thus demonstrating the power of the active beam dump approach for the dark matter search.
↳ hep-exhep-phPRL(2019)·292 citations
24*
Search for $Ω (2012) \to K Ξ (1530) \to K π Ξ$ at Belle
Belle Collaboration: S. Jia🇨🇳 · C. P. Shen🇨🇳 · I. Adachi🇯🇵 · J. K. Ahn🇰🇷 · H. Aihara🇯🇵 · S. Al Said🇸🇦 · D. M. Asner🇺🇸 · T. Aushev🇷🇺 · R. Ayad🇸🇦 · V. Babu🇩🇪 · S. Bahinipati🇮🇳 · A. M. Bakich🇦🇺 and 182 other authors
Using data samples of $e^{+} e^{-}$ collisions collected at the $Υ (1 S)$ , $Υ (2 S)$ , and $Υ (3 S)$ resonances with the Belle detector, we search for the three-body decay of the $Ω (2012)$ baryon to $K π Ξ$ . This decay is predicted to dominate for models describing the $Ω (2012)$ as a $K Ξ (1530)$ molecule. No significant $Ω (2012)$ signals are observed in the studied channels, and 90\% credibility level upper limits on the ratios of the branching fractions relative to $K Ξ$ decay modes are obtained.
↳ hep-exhep-phPRD(2019)·45 citations
25*
Quasinormal modes of black holes in a toy-model for cumulative quantum gravity
Aurélien Barrau🇫🇷 · Killian Martineau🇫🇷 · Jeremy Martinon🇫🇷 · Flora Moulin🇫🇷
The idea that quantum gravity effects might leak outside the horizon of a black hole has recently been intensively considered. In this study, we calculate the quasinormal modes as a function of the location and amplitude of a generic metric perturbation distorting to the Schwarzschild spacetime. We conclude on the possible observability of quantum metric corrections by current and future gravitational wave experiments.
↳ gr-qcastro-ph.COhep-phPLB(2019)·20 citations
26*
An update on fine-tunings in the triple-alpha process
Timo A. Lähde🇩🇪 · Ulf-G. Meißner🇩🇪 · Evgeny Epelbaum🇩🇪
The triple-alpha process, whereby evolved stars create carbon and oxygen, is believed to be fine-tuned to a high degree. Such fine-tuning is suggested by the unusually strong temperature dependence of the triple-alpha reaction rate at stellar temperatures. This sensitivity is due to the resonant character of the triple-alpha process, which proceeds through the so-called "Hoyle state" of $^{12}$ C with spin-parity $0^{+}$ . The question of fine-tuning can be studied within the {\it ab initio} framework of nuclear lattice effective field theory, which makes it possible to relate {\it ad hoc} changes in the energy of the Hoyle state to changes in the fundamental parameters of the nuclear Hamiltonian, which are the light quark mass $m_{q}$ and the electromagnetic fine-structure constant. Here, we update the effective field theory calculation of the sensitivity of the triple-alpha process to small changes in the fundamental parameters. In particular, we consider recent high-precision lattice QCD calculations of the nucleon axial coupling $g_{A}$ , as well as new and more comprehensive results from stellar simulations of the production of carbon and oxygen. While the updated stellar simulations allow for much larger {\it ad hoc} shifts in the Hoyle state energy than previously thought, recent lattice QCD results for the nucleon S-wave singlet and triplet scattering lengths now disfavor the scenario of no fine-tuning in the light quark mass $m_{q}$ .
↳ nucl-thastro-ph.SRhep-phhep-thEPJA(2020)·19 citations
27*
$B_{s} \to D_{s} ℓ ν$ Form Factors for the full $q^{2}$ range from Lattice QCD with non-perturbatively normalized currents
E. McLean🇬🇧 · C. T. H. Davies🇬🇧 · J. Koponen🇯🇵 · A. T. Lytle🇮🇹
We present a lattice QCD determination of the $B_{s} \to D_{s} ℓ ν$ scalar and vector form factors over the full physical range of momentum transfer. The result is derived from correlation functions computed using the Highly Improved Staggered Quark (HISQ) formalism, on the second generation MILC gluon ensembles accounting for up, down, strange and charm contributions from the sea. We calculate correlation functions for three lattice spacing values and an array of unphysically light $b$ -quark masses, and extrapolate to the physical value. Using the HISQ formalism for all quarks means that the lattice current coupling to the $W$ can be renormalized non-perturbatively, giving a result free from perturbative matching errors for the first time. Our results are in agreement with, and more accurate than, previous determinations of these form factors. From the form factors we also determine the ratio of branching fractions that is sensitive to violation of lepton universality: $R (D_{s}) = B (B_{s} \to D_{s} τ ν_{τ}) / B (B_{s} \to D_{s} ℓ ν_{l})$ , where $ℓ$ is an electron or a muon. We find $R (D_{s}) = 0.2987 (46)$ , which is also more accurate than previous lattice QCD results. Combined with a future measurement of $R (D_{s})$ , this could supply a new test of the Standard Model. We also compare the dependence on heavy quark mass of our form factors to expectations from Heavy Quark Effective Theory.
↳ hep-lathep-phPRD(2020)·134 citations
28*
Cross-correlation between 21-cm radiation and CMB B modes from the cosmic birefringence in the presence of a light scalar field
Kenji Kadota🇰🇷 · Junpei Ooba🇯🇵 · Hiroyuki Tashiro🇯🇵 · Kiyotomo Ichiki🇯🇵 · Guo-Chin Liu🇹🇼
We study the cross-correlation between the 21cm and CMB B mode fluctuations which are induced by the cosmic birefringence when the non-constant scalar field couples to the electromagnetic field strength. Such multi-wavelength signals can potentially probe the reionization history of the Universe and also explore the nature of fundamental physics such as the parity violation and the scalar field dynamics in the early Universe. We illustrate the feasibility to detect such 21cm-B mode cross-correlations through commonly discussed scalar field models, the quintessence-like scalar field which is responsible for the current dark energy and the axion-like scalar field which is responsible for the current dark matter density.
↳ astro-ph.COhep-phPRD(2019)·6 citations
29*
Experimental summary: QCD session of the 54th Rencontres de Moriond (Moriond QCD 2019)
Vincenzo M. Vagnoni🇮🇹
The conference included about 90 talks covering a plethora of different sectors, like Higgs physics, electroweak physics, top physics, BSM physics, soft QCD, jets, PDFs, heavy ions, heavy flavours, spectroscopy, etc. A few experimental results are here highlighted.
↳ hep-exhep-ph1 citation
30*
Sound velocity in dense stellar matter with strangeness and compact stars
Chengjun Xia🇨🇳 · Zhenyu Zhu🇨🇳 · Xia Zhou🇨🇳 · Ang Li🇨🇳
The phase state of dense matter in the intermediate density range ( $\sim$ 1-10 times the nuclear saturation density) is both intriguing and unclear and could have important observable effects in the present gravitational wave era of neutron stars. As the matter density increases in compact stars, the sound velocity is expected to approach the conformal limit ( $c_{s} / c = 1/ 3$ ) at high densities and should also fulfill the causality limit ( $c_{s} / c < 1$ ). However, its detailed behavior remains a hot topic of debate. It was suggested that the sound velocity of dense matter could be an important indicator for a deconfinement phase transition, where a particular shape might be expected for its density dependence. In this work, we explore the general properties of the sound velocity and the adiabatic index of dense matter in hybrid stars, as well as in neutron stars and quark stars. Various conditions are employed for hadron-quark phase transition with varying interface tension. We find that the expected behavior of the sound velocity can also be achieved by the nonperturbative properties of the quark phase, in addition to a deconfinement phase transition. And it leads to a more compact star with a similar mass. We then propose a new class of quark star equation of states, which could be tested by future high-precision radius measurements of pulsar-like objects.
↳ nucl-thastro-ph.HEastro-ph.SRhep-phCPC(2021)·58 citations
31*
Mapping the Phases of Quantum Chromodynamics with Beam Energy Scan
Adam Bzdak🇵🇱 · ShinIchi Esumi🇯🇵 · Volker Koch🇺🇸 · Jinfeng Liao🇺🇸 · Mikhail Stephanov🇺🇸 · Nu Xu🇨🇳
We review the present status of the search for a phase transition and critical point as well as anomalous transport phenomena in Quantum Chromodynamics (QCD), with an emphasis on the Beam Energy Scan program at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. We present the conceptual framework and discuss the observables deemed most sensitive to a phase transition, QCD critical point, and anomalous transport, focusing on fluctuation and correlation measurements. Selected experimental results for these observables together with those characterizing the global properties of the systems created in heavy ion collisions are presented. We then discuss what can be already learned from the currently available data about the QCD critical point and anomalous transport as well as what additional measurements and theoretical developments are needed in order to discover these phenomena.
↳ nucl-thhep-lathep-phnucl-exPhys.Rept.(2020)·616 citations
32*
Limiting fragmentation as an initial state probe in heavy ion collisions
Kayman J. Gonçalves🇧🇷 · Andre V. Giannini🇧🇷 · David D. Chinellato🇧🇷 · Giorgio Torrieri🇧🇷
We discuss limiting fragmentation within a few currently popular phenomenological models. We show that popular Glauber-inspired models of particle production in heavy ion collisions, such as the two-component model, generally fail to reproduce limiting fragmentation when all energies and system sizes experimentally available are considered. This is due to the energy-dependence of number of participants and number of collisions. We quantify this violation in terms of the model parameters. We also make the same calculation within a Color Glass Condensate scenario and show that the dependence of the saturation scale on the number of participants generally leads to violation of limiting fragmentation. We further argue that wounded parton models, provided the nucleon size and parton density vary predominantly with Bjorken $x$ , could in principle reproduce both multiplicity dependence with energy and limiting fragmentation. We suggest, therefore, that an experimental measurement of deviation from limiting fragmentation in heavy ion collisions, for different system sizes and including the experimentally available range of energies, is a powerful test of initial state models.
↳ nucl-thhep-phPRC(2019)·6 citations
33*
Early-Universe Simulations of the Cosmological Axion
Malte Buschmann🇺🇸 · Joshua W. Foster🇺🇸 · Benjamin R. Safdi🇺🇸
Ultracompact dark matter (DM) minihalos at masses at and below $1 0^{- 12}$ $M_{⊙}$ arise in axion DM models where the Peccei-Quinn (PQ) symmetry is broken after inflation. The minihalos arise from density perturbations that are generated from the non-trivial axion self interactions during and shortly after the collapse of the axion-string and domain-wall network. We perform high-resolution simulations of this scenario starting at the epoch before the PQ phase transition and ending at matter-radiation equality. We characterize the spectrum of primordial perturbations that are generated and comment on implications for efforts to detect axion DM. We also measure the DM density at different simulated masses and argue that the correct DM density is obtained for $m_{a} = 25.2 \pm 11.0$ $μ eV$ .
↳ astro-ph.COhep-phPRL(2020)·323 citations
34*
The scattering amplitude of stringy hadrons I: Strings with opposite charges on their endpoints
Jacob Sonnenschein🇮🇱 · Dorin Weissman🇮🇱 · Shimon Yankielowicz🇮🇱
In this note we describe hadrons: mesons and baryons as strings with electric charges on their endpoints. We consider here only the neutral system with opposite charges coupled to an external constant electric and magnetic fields. We derive certain classical solutions including rotating folded open strings. We write down the mode expansion and canonically quantize the system. The OPEs associated with such strings are determined. We re-derive the non-commutativity of the zero modes and the fact that the charges modify the spacetime metric. We show that the quantum worldsheet energy momentum tensor on the boundary is affected by the endpoint charges and differs from the corresponding Noether current. We determine the generalization of the Veneziano scattering amplitude for such strings in the critical dimension. Phenomenological implications are addressed and in particular we show that the external magnetic field can be tuned so that the amplitude vanishes for particular kinematic setups. We discuss the generalization of such strings to non-critical four dimensional spacetime. In particular we renormalize the divergence of the Polchinski-Strominger effective action associated with the rotating folded string.
↳ hep-thhep-phJHEP(2020)·6 citations
35*
Exact results from the geometry of couplings and the effective action
George Georgiou🇬🇷 · Pantelis Panopoulos🇬🇷 · Eftychia Sagkrioti🇬🇷 · Konstantinos Sfetsos🇬🇷
We invent a method that exploits the geometry in the space of couplings and the known all-loop effective action, in order to calculate the exact in the couplings anomalous dimensions of composite operators for a wide class of integrable $σ$ -models. These involve both self and mutually interacting current algebra theories. We work out the details for important classes of such operators. In particular, we consider the operators built solely from an arbitrary number of currents of the same chirality, the composite operators which factorize into a chiral and an anti-chiral part, as well as those made up of three currents of mixed chirality. Remarkably enough, the anomalous dimensions of the former two sets of operators turn out to vanish. In our approach, loop computations are completely avoided.
↳ hep-thhep-phnlin.SINPB(2019)·13 citations
36*
Direct anthropic bound on the weak scale from supernovae explosions
Guido D'Amico🇺🇸 · Alessandro Strumia🇮🇹 · Alfredo Urbano🇮🇹 · Wei Xue🇨🇭
Core-collapse supernovae presumably explode because trapped neutrinos push the material out of the stellar envelope. This process is directly controlled by the weak scale $v$ : we argue that supernova explosions happen only if fundamental constants are tuned within a factor of few as $v \sim Λ_{QCD}^{3/4} M_{Pl}^{1/4}$ , such that neutrinos are trapped in supernovae for a time comparable to the gravitational time-scale. We provide analytic arguments and simulations in spherical approximation, that need to be validated by more comprehensive simulations. The above result can be important for fundamental physics, because core-collapse supernova explosions seem anthropically needed, as they spread intermediate-mass nuclei presumably necessary for `life'. We also study stellar burning, finding that it does not provide anthropic boundaries on $v$ .
↳ astro-ph.HEastro-ph.SRhep-phhep-thPRD(2019)·30 citations
37*
A maximal-entropy initial state of the Universe as a microscopic description of inflation
Ram Brustein🇮🇱 · A.J.M. Medved🇿🇦
We propose that the initial state of the Universe was an isotropic state of maximal entropy. Such a state can be described in terms of a state of closed, interacting, fundamental strings in their high-temperature Hagedorn phase. The entropy density in this state is equal to the square root of the energy density in Planck units, while the pressure is positive and equal to the energy density. These relations imply a maximally large entropy density and, therefore, a state that cannot be described by a semiclassical spacetime geometry. If one nevertheless insists on an effective semiclassical description of this state, she can do so by ignoring the entropy. This leads to a partially equivalent description in which the pressure appears to be negative and equal in magnitude to the energy density, as if the energy-momentum tensor was that of a cosmological constant. From this effective perspective, the state describes a period of string-scale inflation. The bound state of strings ultimately decays, possibly by a process akin to Hawking radiation, and undergoes a transition into a phase of hot radiation. But, from the effective perspective, the same decay corresponds to the heating of the Universe at the end of inflation. Small quantum mechanical fluctuations in the initial state lead to scale-invariant temperature anisotropies in the hot radiation. The temperature anisotropies are interpreted in the effective description as arising from quantum fluctuations of the curvature and an effective inflaton field. The stringy microscopic description determines the parameters of the model of inflation, as well as the cosmological observables, in terms of the string length scale and coupling strength. Our framework is similar, conceptually, to a recent description of black holes in terms of a maximal entropy state of strings in the Hagedorn phase.
↳ hep-thgr-qchep-phPRD(2020)·4 citations
38*
Influence of initial-state momentum anisotropy on the final-state collectivity in small collision systems
Maowu Nie🇨🇳 · Li Yi🇨🇳 · Jiangyong Jia🇺🇸 · Guoliang Ma🇨🇳
A multi-phase transport model is used to understand the origin of long-range collective azimuthal correlations in small-system collisions. To disentangle between collectivity associated with initial-state intrinsic momentum anisotropy and the collectivity arising as a final-state response to the collision geometry, we studied the development of collectivity in 5.02 TeV $p$ +Pb collisions with both initial-state and final-state effects included. We find that the initial momentum anisotropy may not be fully isotropized through parton interactions, and the final-state partonic collectivity in general are correlated with both the initial momentum anisotropy and the shape of the collision geometry. The initial momentum anisotropy also influences the event by event fluctuation of collective flow. Therefore the mere evidence of geometry response of the collective flow can not rule out the presence of large contributions from the initial state.
↳ nucl-thhep-phnucl-exPRC(2019)·18 citations
39*
A First Look on 3D Effects in Open Axion Haloscopes
Stefan Knirck🇩🇪 · Jan Schütte-Engel🇩🇪 · Alexander J. Millar🇸🇪 · Javier Redondo🇪🇸 · Olaf Reimann🇩🇪 · Andreas Ringwald🇩🇪 · Frank D. Steffen🇩🇪
We explore finite size 3D effects in open axion haloscopes such as a dish antenna, a dielectric disk and a minimal dielectric haloscope consisting of a mirror and one dielectric disk. Particularly dielectric haloscopes are a promising new method for detecting dark matter axions in the mass range above $40 μ eV$ . By using two specialized independent approaches - based on finite element methods and Fourier optics - we compute the electromagnetic fields in these settings expected in the presence of an axion dark matter field. This allows us to study diffraction and near field effects for realistically sized experimental setups in contrast to earlier idealized 1D studies with infinitely extended mirrors and disks. We also study axion velocity effects and disk tiling. Diffraction effects are found to become less relevant towards larger axion masses and for the larger disk radii for example aimed at in full size dielectric haloscopes such as MADMAX. The insights of our study not only provide a foundation for a realistic modelling of open axion dark matter search experiments in general, they are in particular also the first results taking into account 3D effects for dielectric haloscopes.
↳ physics.ins-dethep-exhep-phJCAP(2019)·35 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.