Tue·Nov 20, 2018Tuesday·November 20, 2018

1. 01*

   Quarkonium In-Medium Transport Equation Derived from First Principles

   Xiaojun Yao🇺🇸 · Thomas Mehen🇺🇸

   We use the open quantum system formalism to study the dynamical in-medium evolution of quarkonium. The system of quarkonium is described by potential non-relativistic QCD while the environment is a weakly coupled quark-gluon plasma in local thermal equilibrium below the melting temperature of the quarkonium. Under the Markovian approximation, it is shown that the Lindblad equation leads to a Boltzmann transport equation if a Wigner transform is applied to the system density matrix. Our derivation illuminates how the microscopic time-reversibility of QCD is consistent with the time-irreversible in-medium evolution of quarkonium states. Static screening, dissociation and recombination of quarkonium are treated in the same theoretical framework. In addition, quarkonium annihilation is included in a similar way, although the effect is negligible for the phenomenology of the current heavy ion collision experiments. The methods used here can be extended to study quarkonium dynamical evolution inside a strongly coupled QGP, a hot medium out of equilibrium or cold nuclear matter, which is important to studying quarkonium production in heavy ion, proton-ion, and electron-ion collisions.

   hep-phnucl-thPRD(2019)·128 citations
2. 02*

   Testing generalized CP symmetries with precision studies at DUNE

   Newton Nath🇨🇳 · Rahul Srivastava🇪🇸 · José W. F. Valle🇪🇸

   We examine the capabilities of the DUNE experiment in probing leptonic CP violation within the framework of theories with generalized CP symmetries characterized by the texture zeros of the corresponding CP transformation matrices. We investigate DUNE's potential to probe the two least known oscillation parameters, the atmospheric mixing angle ${\theta }_{23}$ and the Dirac CP-phase ${\delta }_{\mathrm{CP}}$. We fix theory-motivated benchmarks for (${\sin }^2{\theta }_{23},{\delta }_{\mathrm{CP}}$) and take them as true values in our simulations. Assuming 3.5 years of neutrino running plus 3.5 years in the antineutrino mode, we show that in all cases DUNE can significantly constrain and in certain cases rule out the generalized CP texture zero patterns.

   hep-phhep-exPRD(2019)·24 citations
3. 03*

   Understanding the dynamics of field theories far from equilibrium

   Kirill Boguslavski🇫🇮

   In recent years, there have been important advances in understanding the far-from-equilibrium dynamics in different physical systems. In ultra-relativistic heavy-ion collisions, the combination of different methods led to the development of a weak-coupling description of the early-time dynamics. The numerical observation of a classical universal attractor played a crucial role for this. Such attractors, also known as non-thermal fixed points (NTFPs), have been now predicted for different scalar and gauge theories. An important universal NTFP emerges in scalar theories modeling ultra-cold atoms, inflation or dark matter, and its scaling properties have been recently observed in an ultra-cold atom experiment. In this proceeding, recent progress in selected topics of the far-from-equilibrium evolution in these systems will be discussed. A new method to extract the spectral function numerically is a particularly promising tool to better understand their microscopic properties.

   hep-phcond-mat.quant-gashep-latPoS(2018)·2 citations
4. 04*

   Intriguing properties of multiplicity distributions

   Maciej Rybczyński🇵🇱 · Grzegorz Wilk🇵🇱 · Zbigniew Włodarczyk🇵🇱

   Multiplicity distributions exhibit, after closer inspection, peculiarly enhanced void probability and oscillatory behavior of the modified combinants. We discuss the possible sources of these oscillations and their impact on our understanding of the multiparticle production mechanism. Theoretical understanding of both phenomena within the class of compound distributions is presented.

   hep-phnucl-thPRD(2019)·21 citations
5. 05*

   Search for the ${\Sigma }^{\ast }$ state in ${\Lambda }_c^{+}\to {\pi }^{+}{\pi }^0{\pi }^{-}{\Sigma }^{+}$ decay by triangle singularity

   Ju-Jun Xie🇨🇳 · Eulogio Oset🇪🇸

   A ${\Sigma }^{\ast }$ resonance with spin-parity $J^P=1/2^{-}$ and mass in the vicinity of the $\bar{K}N$ threshold has been predicted in the unitary chiral approach and inferred from the analysis of CLAS data on the $\gamma p\to K^{+}{\pi }^0{\Sigma }^0$ reaction. In this work, based on the dominant Cabibbo favored weak decay mechanism, we perform a study of ${\Lambda }_c^{+}\to {\pi }^{+}{\pi }^0{\Sigma }^{\ast }$ with the possible ${\Sigma }^{\ast }$ state decaying into ${\pi }^{-}{\Sigma }^{+}$ through a triangle diagram. This process is initiated by ${\Lambda }_c^{+}\to {\pi }^{+}{\bar{K}}^{\ast }N$, then the ${\bar{K}}^{\ast }$ decays into $\bar{K}\pi$ and $\bar{K}N$ produce the ${\Sigma }^{\ast }$ through a triangle loop containing ${\bar{K}}^{\ast }N\bar{K}$ which develops a triangle singularity. We show that the ${\pi }^{-}{\Sigma }^{+}$ state is generated from final state interaction of $\bar{K}N$ in $S$-wave and isospin $I=1$, and the ${\Lambda }_c^{+}\to {\pi }^{+}{\pi }^0{\pi }^{-}{\Sigma }^{+}$ decay can be used to study the possible ${\Sigma }^{\ast }$ state around the $\bar{K}N$ threshold. The proposed decay mechanism can provide valuable information on the nature of the ${\Sigma }^{\ast }$ resonance and can in principle be tested by facilities such as LHCb, BelleII and BESIII.

   hep-phhep-exnucl-exnucl-thPLB(2019)·27 citations
6. 06*

   A diagrammatic analysis of two-body charmed baryon decays with flavor symmetry

   H.J. Zhao🇨🇳 · Yan-Li Wang🇨🇳 · Y.K. Hsiao🇨🇳 · Yao Yu🇨🇳

   We study the two-body anti-triplet charmed baryon decays based on the diagrammatic approach with $SU(3)$ flavor symmetry. We extract the two $W$-exchange effects as $E_{\mathbf{B}}$ and $E^{\prime }$ that contribute to the ${\Lambda }_c^{+}\to {\Xi }^0{K}^{+}$ decay, together with the relative phases, where $E_{\mathbf{B}}$ gives the main contribution. Besides, we find that $\mathcal{B}({\Lambda }_c^{+}\to p{\pi }^0)=(0.8_{-0.8}^{+0.9})\times 10^{-4}$, which is within the experimental upper bound. Particularly, we obtain $\mathcal{B}({\Xi }_c^{+}\to {\Xi }^0{\pi }^{+})=(9.3\pm 3.6)\times 10^{-3}$, $\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{\pi }^{+},{\Lambda }^0{\bar{K}}^0)=(19.3\pm 2.8,8.3\pm 5.0)\times 10^{-2}$ and $\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{K}^{+})=(5.6\pm 0.8)\times 10^{-4}$, which all agree with the data. For the singly Cabibbo suppressed ${\Lambda }_c^{+}$ decays, we predict that $\mathcal{B}({\Lambda }_c^{+}\to n{\pi }^{+},p{\eta }^{\prime },{\Sigma }^{+}{K}^0)=(7.7\pm 2.0,7.1\pm 1.4,19.1\pm 4.8)\times 10^{-4}$, which are accessible to the experiments at BESIII, BELLEII and LHCb.

   hep-phJHEP(2020)·62 citations
7. 07*

   Fate of the charm baryon ${\Lambda }_c$ in cold and hot nuclear matter

   Shigehiro Yasui🇯🇵

   I discuss the properties of the ${\Lambda }_c$ baryon in nuclear matter at zero or finite temperature. Starting from the Lagrangian based on the heavy-quark effective theory, I derive the effective Lagrangian for the ${\Lambda }_c$ baryon existing as an impurity particle. Adopting the one-loop calculation for nucleons, I derive the effective potential as the quantity for measuring the stability of the ${\Lambda }_c$ baryon in nuclear matter. The parameters in the Lagrangian are fitted to reproduce the scattering length of the nucleon and the ${\Lambda }_c$ baryon estimated in the lattice QCD simulations and the chiral extrapolations. I present that the ${\Lambda }_c$ baryon is bound in nuclei with the binding energy of about 20 MeV at normal nuclear-matter density. I discuss the case that the ${\Lambda }_c$ baryon moves with a constant velocity. I also discuss an increase of the nucleon number density near the ${\Lambda }_c$ baryon in nuclear matter, and show that the ${\Lambda }_c$ baryon is a useful probe to research the nuclear systems at high density.

   hep-phnucl-thPRC(2019)·7 citations
8. 08*

   The role of the thermal $f_0(500)$ in chiral symmetry restoration

   S.Ferreres-Solé🇳🇱 · A. Gómez Nicola🇪🇸 · A. Vioque-Rodríguez🇪🇸

   We show that the $\sigma /f_0(500)$ state with finite-temperature $T$ corrections to its spectral properties included, plays an essential role for the description of the scalar susceptibility ${\chi }_S$, signaling chiral symmetry restoration. First, we use the $O(4)$ Linear Sigma Model as a testbed to derive the connection between ${\chi }_S$ and the $\sigma$ propagator and to check the validity and reliability of the approach where ${\chi }_S$ is saturated by the $\sigma /f_0(500)$ inverse self-energy, which we calculate at finite $T$ to one loop. A more accurate phenomenological description is achieved by considering the saturation approach as given by the thermal $f_0(500)$ state generated in Unitarized Chiral Perturbation Theory. Such approach allows to describe fairly well recent lattice data within the uncertainty range given by the UChPT parameters. Finally, we compare the UChPT saturated description with one based on the Hadron Resonance Gas, for which the hadron mass dependences are extracted from recent theoretical analysis. Several fits to lattice data are performed, which confirm the validity of the thermal $f_0(500)$ saturated approach and hence the importance of that thermal state for chiral symmetry restoration.

   hep-phPRD(2019)·24 citations
9. 09*

   Light pseudoscalar meson and doubly charmed baryon scattering lengths with heavy diquark-antiquark symmetry

   Lu Meng🇨🇳 · Shi-Lin Zhu🇨🇳

   We adopt the heavy baryon chiral perturbation theory (HBChPT) to calculate the scattering lengths of $\varphi B_{cc}^{(\ast )}$ up to $\mathcal{O}(p^3)$, where $\varphi$ is the pseudoscalar mesons. The recoil effect and the mass splitting between the spin-$\frac{1}{2}$ and spin-$\frac{3}{2}$ doubly charmed baryons are included. In order to give the numerical results, we construct the chiral Lagrangians with heavy diquark-antiquark (HDA) symmetry in a formally covariant approach. Then, we relate the low energy constants (LECs) of the doubly charmed baryons to those of $D^{(\ast )}$ mesons. The LECs for the $\varphi D^{(\ast )}$ scattering are estimated in two scenarios, fitting lattice QCD results and using the resonance saturation model. The chiral convergence of the first scenario is not good enough due to the the large strange quark mass and the presence of the possible bound states, virtual states and resonance. The final results for two scenarios are consistent with each other. The interaction for the $[\pi {\Xi }_{cc}^{(\ast )}{]}^{(1/2)}$, $[K{\Xi }_{cc}^{(\ast )}{]}^{(0)}$, $[K{\Omega }_{cc}^{(\ast )}{]}^{(1/2)}$, $[\eta {\Xi }_{cc}^{(\ast )}{]}^{(1/2)}$, $[\eta {\Omega }_{cc}^{(\ast )}{]}^{(0)}$ and $[\bar{K}{\Xi }_{cc}^{(\ast )}{]}^{(0)}$ channels are attractive. The most attractive channel $[\bar{K}{\Xi }_{cc}^{(\ast )}{]}^{(0)}$ may help to form the partner states of the $D_{s0}^{\ast }(2317)$ ($D_{s1}(2460)$) in the doubly heavy sector.

   hep-phhep-exhep-latnucl-thPRD(2019)·27 citations
10. 10*

    Zero point energy of composite particles: The medium effects

    Toru Kojo🇨🇳

    We analyze the zero point energy of composite particles (or resonances) which are dynamically created from relativistic fermions. We compare the zero point energies in medium to the vacuum one, taking into account the medium modification of the constituent particles. Treating composite particles as if quasi-particles, their zero point energies contain the quadratic and logarithmic UV divergences even after the vacuum subtraction. The coefficients of these divergences come from the difference between the vacuum and in-medium fermion propagators. We argue that such apparent divergences can be cancelled by consistently using fermion propagators to compute the quasi-particle contributions as well as their interplay, provided that the self-energies of the constituents at large momenta approach to the vacuum ones sufficiently fast. In the case of quantum chromodynamics, mesons and baryons, which may be induced or destroyed by medium effects, yield the in-medium divergences in the zero point energies, but the divergences are assembled to cancel with those from the quark zero-point energy. This is particularly important for unified descriptions of hadronic and quark matter which may be smoothly connected by the quark-hadron continuity.

    hep-phastro-ph.HEhep-thnucl-thPRD(2020)·5 citations
11. 11*

    Production of double charmed baryons with the excited heavy diquark at LHC

    A. V. Berezhnoy🇷🇺 · I. N. Belov🇷🇺 · A. K. Likhoded🇷🇺

    The yield of doubly charmed baryons with excited heavy diquark in $S$ wave and $P$ wave states has been estimated at LHC energies. The observation possibility of such baryons is discussed.

    hep-phInt.J.Mod.Phys.A(2019)·16 citations
12. 12*

    Semi-Exclusive Heavy Quark Production in Charged-Current Deep Inelastic Scattering

    Nicola Pessina🇮🇹

    Main aim of this research consists in the description of Deep Inelastic Scattering (DIS) processes mediated by Charged Currents (CC), producing a massive quark in the final state. Formalism of DIS processes has been investigated in depth, including mass contributions for charged lepton. Semi-exclusive partonic coefficient functions for heavy quark production up to Next-to-Leading Order have been carried out in the context of perturbative QCD.

    hep-ph0 citations
13. 13*

    New physics in inclusive semileptonic $B$ decays including nonperturbative corrections

    Saeed Kamali🇺🇸

    In this work we study the effects of New Physics (NP) operators on the inclusive $\bar{B}\to X_c{\tau }^{-}{\bar{\nu }}_{\tau }$ decay including power $(\mathcal{O}(1/m_b^2))$ corrections in the NP operators. In analogy with $R(D^{(\ast )})$ observables, we study the observable $R(X_c)=\frac{\mathcal{B}(\bar{B}\to X_c{\tau }^{-}{\bar{\nu }}_{\tau })}{\mathcal{B}(\bar{B}\to X_c{\ell }^{-}{\bar{\nu }}_{\ell })}$. We present some numerical results for $R(X_c)$ and compare the results for this observable with and without power corrections in the NP contributions.

    hep-phhep-exInt.J.Mod.Phys.A(2019)·23 citations
14. 14*

    Fluctuations in small systems

    Stéphane Munier🇫🇷

    We review the main features of event-by-event fluctuations of the content of the Fock states of onia (as models for dilute hadrons, or as bare hadronic components of virtual photons), as well as some of their observable consequences. We briefly address the total scattering cross section of a small onium off a nucleus, then of two small onia. Finally, we explain that the multiplicity in the final state of collisions of large onia with nuclei may directly be related to the gluon density in the former. We provide first predictions for the event-by-event fluctuations of the gluon density.

    hep-phActa Phys.Polon.Supp.(2019)·0 citations
15. 15*

    Conference Summary and Outlook: Particle Physics Past, Present, and Future

    Paul Langacker🇺🇸

    I briefly summarize highlights of ICHEP2018, comment on the 50th anniversary of the Standard Model, and share some of my thoughts for the future.

    hep-phhep-exPoS(2019)·2 citations
16. 16*

    Monte Carlo event generator for the production and decay of string resonances in proton-proton collisions

    Pourya Vakilipourtakalou🇨🇦 · Douglas M. Gingrich🇨🇦

    We describe a Monte Carlo event generator for the production and decay of first and second string resonances through 2 $\to$ 2 partonic and also 2-parton $\to$ $\gamma$-parton scatterings in proton-proton collisions - STRINGS version 1.00. This generator is also capable of producing QCD diparton processes. STRINGS is written in Python 2 and can be interfaced to common hadronization programs using the Les Houches Accord.

    hep-phgr-qchep-exhep-th2 citations
17. 17*

    Studying parton correlations via double parton scatterings in associated quarkonium production at the LHC and the Tevatron

    Nodoka Yamanaka🇫🇷 · Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇫🇷 · Yu-Jie Zhang🇨🇳

    Quarkonium production in proton-proton (pp) collision provides interesting means to study the parton content and their correlations in the proton. Recent LHC and Tevatron data of J/psi + Z, J/psi + W and J/psi +J/psi production suggest the relevance of double parton scatterings (DPSs) as opposed to single parton scatterings (SPSs). In this proceedings contribution, we review the corresponding SPS contributions and discuss their upper limits set up by quark-hadron duality. These allow us to perform an improved extraction of the DPS yields and of their implications.

    hep-phhep-exnucl-exnucl-thPoS(2019)·1 citation
18. 18*

    Dilepton production and elliptic flow from an anisotropic quark-gluon plasma

    Babak S. Kasmaei🇺🇸 · Michael Strickland🇺🇸

    We calculate the yield and elliptic flow of mid-rapidity dileptons emitted from the quark-gluon plasma generated in Pb-Pb collisions at LHC. We use relativistic anisotropic hydrodynamics for the 3+1 dimensional evolution of the quark-gluon plasma and convolve this with the momentum-anisotropic local rest frame production rate for dileptons. The effects of momentum anisotropy of the quark distribution functions, viscosity to entropy density ratio, centrality of the collisions, and initial momentum anisotropy on the results are investigated and discussed.

    hep-phnucl-thPRD(2019)·39 citations
19. 19*

    Accessing Linearly Polarized Gluon Distribution in $J/\psi$ Production at the Electron-Ion Collider

    Raj Kishore🇮🇳 · Asmita Mukherjee🇮🇳

    We calculate the $cos2\varphi$ asymmetry in $J/\psi$ production in electron-proton collision for the kinematics of the planned electron-ion collider (EIC). This directly probes the Weiszäcker-Williams (WW) type linearly polarized gluon distribution. Assuming generalized factorization, we calculate the asymmetry at next-to-leading-order (NLO) when the energy fraction of the $J/\psi$ satisfies $z<1$ and the dominating subprocess is ${\gamma }^{\ast }+g\to c+\bar{c}+g$. We use non-relativistic QCD based color singlet model for $J/\psi$ production. We investigate the small $x$ region which will be accessible at the EIC. We present the upper bound of the asymmetry, as well as estimate it using a (i) Gaussian type parametrization for the TMDs and (ii) McLerran-Venugopalan model at small $x$. We find small but sizable asymmetry in all the three cases.

    hep-phPRD(2019)·29 citations
20. 20*

    Threshold effects in electron-positron pair creation from the vacuum: Stabilization and longitudinal vs transverse momentum sharing

    K. Krajewska🇵🇱 · J. Z. Kamiński🇵🇱

    Momentum distributions of electron-positron pairs created from the vacuum by an oscillating in time electric field are calculated in the framework of quantum field theory. A pronounced enhancement of those distributions is observed as the frequency of the electric field passes across the one-photon threshold. Below that threshold the pairs preferentially carry a longitudinal momentum, while above the threshold they tend to carry a transverse momentum. Such momentum sharing has an impact on the number of produced pairs: It grows fast with increasing the field frequency below the threshold but it saturates at a roughly constant value above it. On the other hand, at the fixed frequency above the one-photon threshold, the number of pairs scales quadratically with the field strength. This typically perturbative scaling holds even for large electric fields. Thus, the validity of the perturbation theory is extended here to processes which result in creation of particles with substantial transverse momenta.

    hep-phphysics.atom-phPRA(2019)·12 citations
21. 21*

    Conventional and Hybrid $B_c$ Mesons in an Extended Potential Model

    Nosheen Akbar🇵🇰 · M. Atif Sultan🇵🇰 · Bilal Masud🇵🇰 · Faisal Akram🇵🇰

    Using our analytical expressions that well model the lattice simulations of the gluonic excitations, we use the extended quark potential model to study the effects of orbital and radial excitations on the masses and sizes of conventional and hybrid $B_c$ mesons. A non relativistic formalism is used to numerically calculate the wave functions using the shooting method; this allows us also calculating the $E1$, $M1$ radiative partial widths for conventional meson to meson and hybrid to hybrid transitions. We incorporate spin mixing and compare our calculated spectrum and decay widths with the available experimental $B_c$ masses and the theoretically predicted spectra and the decay widths by other groups. Our results can help consider both conventional and hybrid quantum numbers to $B_c$ mesons as experimental results become available.

    hep-phEPJA(2019)·23 citations
22. 22*

    Analysis of $CP$ violation in $D^0\to K^{+}{K}^{-}{\pi }^0$

    Hang Zhou🇨🇳 · Bo Zheng🇨🇳 · Zhen-Hua Zhang🇨🇳

    We study the $CP$ violation induced by the interference between two intermediate resonances $K^{\ast }(892{)}^{+}$ and $K^{\ast }(892{)}^{-}$ in the phase space of singly-Cabibbo-suppressed decay $D^0\to K^{+}{K}^{-}{\pi }^0$. We adopt the factorization-assisted topological approach in dealing with the decay amplitudes of $D^0\to K^{\pm }{K}^{\ast }(892{)}^{\mp }$. The $CP$ asymmetries of two-body decays are predicted to be very tiny, which are $(-1.27\pm 0.25)\times 10^{-5}$ and $(3.86\pm 0.26)\times 10^{-5}$ respectively for $D^0\to K^{+}{K}^{\ast }(892{)}^{-}$ and $D^0\to K^{-}{K}^{\ast }(892{)}^{+}$. While the differential $CP$ asymmetry of $D^0\to K^{+}{K}^{-}{\pi }^0$ is enhanced because of the interference between the two intermediate resonances, which can reach as large as $3\times 10^{-4}$. For some NPs which have considerable impacts on the chromomagnetic dipole operator $O_{8g}$, the global $CP$ asymmetries of $D^0\to K^{+}{K}^{\ast }(892{)}^{-}$ and $D^0\to K^{-}{K}^{\ast }(892{)}^{+}$ can be then increased to $(0.56\pm 0.08)\times 10^{-3}$ and $(-0.50\pm 0.04)\times 10^{-3}$, respectively. The regional $CP$ asymmetry in the overlapped region of the phase space can be as large as $(1.3\pm 0.3)\times 10^{-3}$.

    hep-phAdv.High Energy Phys.(2018)·6 citations
23. 23*

    Minimal Gauged U(1)${}_{L_{\alpha }-L_{\beta }}$ Models Driven into a Corner

    Kento Asai🇯🇵 · Koichi Hamaguchi🇯🇵 · Natsumi Nagata🇯🇵 · Shih-Yen Tseng🇯🇵 · Koji Tsumura🇯🇵

    It is well known that the differences between the lepton numbers can be gauged with the Standard Model matter content. Such extended gauge theories, dubbed as the gauged U(1)${}_{L_{\alpha }-L_{\beta }}$ models, have been widely discussed so far as potential candidates for physics beyond the Standard Model. In this work, we study the minimal versions of these gauge theories, where three right-handed neutrinos as well as a single U(1)${}_{L_{\alpha }-L_{\beta }}$ symmetry breaking Higgs field---an SU(2)${}_L$ singlet or doublet---are introduced. In these minimal models, the neutrino mass terms are constrained by the gauge symmetry, which result in the two-zero texture or two-zero minor structure of neutrino mass matrices. Such restrictive forms of neutrino mass matrices lead to non-trivial predictions for the neutrino oscillation parameters as well as the size of the mass eigenvalues. We find that due to this restriction the minimal gauged U(1)${}_{L_{\alpha }-L_{\beta }}$ models are either incompatible with the observed values of the neutrino parameters or in strong tension with the Planck 2018 limit on the sum of the neutrino masses. Only the U(1)${}_{L_{\mu }-L_{\tau }}$ model with an SU(2)${}_L$ singlet U(1)${}_{L_{\mu }-L_{\tau }}$-breaking field barely evades the limit, which can be tested in the future neutrino experiments.

    hep-phPRD(2019)·88 citations
24. 24*

    Direct searches motivated by recent $B$-anomalies

    Darius A. Faroughy🇸🇮

    We discuss the physics case for direct searches at the LHC motivated by the $B$-physics anomalies. After correlating semi-tauonic $B$ decays to di-tau production at the LHC, and discussing the possible models solving the $B$-anomalies, we show how current LHC data in $\tau \bar{\tau }$ tails exclude most beyond the SM scenarios except for a handful of leptoquark (LQ) models. We analyze in detail the impact of LHC searches for some of these LQ solutions using current data. In particular, we focus on the well known $U_1\sim (3,1{)}_{2/3}$ vector LQ solution as well as the GUT-inspired scalar LQ solutions, $R_2\sim (3,2{)}_{7/6}$ and $S_3\sim (\bar{3},3{)}_{1/3}$. By exploiting the complementarity between high-$p_T$ searches in di-tau tails and the lepton flavor violating decays $B\to K\mu \tau$ and $\tau \to \mu \varphi$ we argue that these model can be cornered by the LHC, Belle II and LHCb in the near future.

    hep-phhep-exSciPost Phys.Proc.(2019)·3 citations
25. 25*

    Electric dipole transitions of $1P$ bottomonia

    Jorge Segovia🇪🇸 · Sebastian Steinbeißer🇩🇪 · Antonio Vairo🇩🇪

    We compute the electric dipole transitions ${\chi }_{bJ}(1P)\to \gamma {\rm Y}(1S)$, with $J=0,1,2$, and $h_b(1P)\to \gamma {\eta }_b(1S)$ in a model-independent way. We use potential non-relativistic QCD (pNRQCD) at weak coupling with either the Coulomb potential or the complete static potential incorporated in the leading order Hamiltonian. In the last case, the perturbative series shows very mild scale dependence and a good convergence pattern, allowing predictions for all the transition widths. Assuming ${\Lambda }_{\text{QCD}}\ll m{v}^2$, the precision that we reach is $k_{\gamma }^3/(mv{)}^2\times \mathcal{O}(v^2)$, where $k_{\gamma }$ is the photon energy, $m$ is the mass of the heavy quark and $v$ its relative velocity. Our results are: $\Gamma ({\chi }_{b0}(1P)\to \gamma {\rm Y}(1S))=28_{-2}^{+2}\text{keV}$, $\Gamma ({\chi }_{b1}(1P)\to \gamma {\rm Y}(1S))=37_{-2}^{+2}\text{keV}$, $\Gamma ({\chi }_{b2}(1P)\to \gamma {\rm Y}(1S))=45_{-3}^{+3}\text{keV}$ and $\Gamma (h_b(1P)\to \gamma {\eta }_b(1S))=63_{-6}^{+6}\text{keV}$.

    hep-phhep-exPRD(2019)·16 citations
26. 26*

    Large-$N_c$ QCD and tetraquarks

    Hagop Sazdjian🇫🇷

    Tetraquark properties are examined in the limit of large $N_c$ of color in QCD. The qualitative differences between molecular and compact tetraquarks are outlined. Consequences of the possible existence of compact tetraquarks are analyzed and shown to lead to upper bounds in the $N_c$-behavior of their decay widths. Open questions on theoretical grounds, related to the dynamics of systems composed of two quarks and two antiquarks, are addressed.

    hep-phPoS(2018)·1 citation
27. 27*

    Searching for the Odderon in the diffractive $f_2(1270)$ photoproduction at $pA$ collisions

    V. P. Goncalves🇧🇷

    Although the Odderon is an unambiguous prediction of Quantum Chromodynamics, its existence still was not confirmed experimentally. One of the processes where the Odderon contribution is expected to be dominant is the diffractive photoproduction of tensor mesons. In this paper we study the diffractive $f_2(1270)$ photoproduction in $pA$ collisions at LHC and RHIC considering the model of the stochastic vacuum to treat the non - perturbative process. We demonstrate that this process dominates the $f_2$ production at mid - rapidities, and large values for the cross section are predicted. Our results indicate that the experimental analysis of this final state is, in principle, feasible and can be used to probe the Odderon.

    hep-phhep-exnucl-thEPJC(2019)·8 citations
28. 28*

    Correction to the energy spectrum of ${}^1{S}_0$ heavy quarkonia due to two-gluon annihilation effect

    Hui-Yun Cao🇨🇳 · Hai-Qing Zhou🇨🇳

    In this work, the non-relativistic asymptotic behavior of the transition $q\overline{q}\to 2g\to q\overline{q}$ in the ${}^1{S}_0$ channel is discussed. Different with the usual calculation which expands the physical amplitude around the quark anti-quark threshold, we take the quark anti-quark pairs as off shell and only expand the expression on the three-dimensional momenta of the quarks and anti-quarks. We calculate the results to order 6. The imagine part of the results after applying the on shell conditions can reproduce the non-relativistic QCD (NRQCD) results in leading order of ${\alpha }_s$. The real part of the results can be used to estimate the mass shift of the ${}^1{S}_0$ heavy quark anti-quark system due to the $2g$ annihilation effect. The results can also be used to estimate the energy shifts of the positronium system due to the two-photon annihilation.

    hep-phnucl-thPRD(2019)·2 citations
29. 29*

    Odderon: models vs experimental data - a short review of recent papers

    Evgenij Martynov🇺🇦 · Basarab Nicolescu🇷🇴

    The surprising low TOTEM datum ${\rho }_{pp}$ = 0.09$\pm$0.01 at 13 TeV \cite{TOTEM-1} generated an important flux of papers, which can be classified in three categories: 1) papers which claim that this result is the first experimental discovery of the Odderon, namely in its maximal form; 2) papers which tried, without success, to find alternative explanations of this result; 3) papers which contest the discovery of the Maximal Odderon. In the present short note we discuss two recent papers belonging to the third category.

    hep-ph7 citations
30. 30*

    Centrality and energy dependence of charged particles in p+A and A+A collisions from running coupling $k_T$-factorization

    Adrian Dumitru🇺🇸 · Andre V. Giannini🇧🇷 · Matthew Luzum🇧🇷 · Yasushi Nara🇯🇵

    We extend the numerical analysis of the energy and centrality dependence of particle multiplicities at midrapidity in high-energy p+A and A+A collisions from a running coupling $k_T$-factorization formula made in~\cite{Dumitru:2018gjm} by considering two unintegrated gluon distributions that were left out. While a good agreement with the experimental data in A+A collisions is achieved, improving the description of those observables in p+A collisions calls for a better understanding of the proton unintegrated gluon distribution at larger values of $x$ and also the use of a realistic impact parameter dependence.

    hep-phnucl-thActa Phys.Polon.Supp.(2019)·3 citations
31. 31*

    Probing QCD approach to thermal equilibrium with ultrahigh energy cosmic rays

    Jorge F. Soriano🇺🇸 · Luis A. Anchordoqui🇺🇸 · Thomas C. Paul🇺🇸 · Thomas J. Weiler🇺🇸

    The Pierre Auger Collaboration has reported an excess in the number of muons of a few tens of percent over expectations computed using extrapolation of hadronic interaction models tuned to accommodate LHC data. Very recently, we proposed an explanation for the muon excess assuming the formation of a deconfined quark matter (fireball) state in central collisions of ultrarelativistic cosmic rays with air nuclei. At the first stage of its evolution the fireball contains gluons as well as $u$ and $d$ quarks. The very high baryochemical potential inhibits gluons from fragmenting into $u\bar{u}$ and $d\bar{d}$, and so they fragment predominantly into $s\bar{s}$ pairs. In the hadronization which follows this leads to the strong suppression of pions and hence photons, but allows heavy hadrons to be emitted carrying away strangeness. In this manner, the extreme imbalance of hadron to photon content provides a way to enhance the muon content of the air shower. In this communication we study theoretical systematics from hadronic interaction models used to describe the cascades of secondary particles produced in the fireball explosion. We study the predictions of one of the leading LHC-tuned models QGSJET II-04 considered in the Auger analysis.

    hep-phastro-ph.HEPoS(2018)·9 citations
32. 32*

    Lepton and Quark Mixing from Stepwise Breaking of Flavor and CP

    Claudia Hagedorn🇩🇰 · Johannes König🇩🇰

    We explain all features of lepton and quark mixing in a scenario with the flavor symmetry Delta (384) and a CP symmetry, where these are broken in several steps. The residual symmetry in the neutrino and up quark sector is a Klein group and CP, while a Z_3 and a Z_{16} symmetry are preserved among charged leptons and down quarks, respectively. If the Klein group in the neutrino sector is further broken down to a single Z_2 symmetry, we obtain predictions for all lepton mixing parameters in terms of one real quantity, whose size is determined by the value of the reactor mixing angle. The Dirac and Majorana phases are fixed, in particular sin (delta) = -0.936. A sum rule, relating these CP phases and the reactor and atmospheric mixing angles, theta_{13} and theta_{23}, is given. In the quark sector, we have for the Cabibbo angle theta_C= sin (pi/16) = 0.195 after the first step of symmetry breaking. This is brought into full accordance with experimental data with the second step of symmetry breaking, where either the Z_{16} group is broken to a Z_8 symmetry in the down quark sector or the Klein group to one Z_2 symmetry only among up quarks. The other two quark mixing angles are generated in the third and last symmetry breaking step, when the residual symmetries in the up and/or down quark sector are further broken. If this step occurs among both up and down quarks, the amount of CP violation in the quark sector is determined by the lepton sector and explaining the current neutrino oscillation data entails that the Jarlskog invariant J_{CP}^q is in very good agreement with experimental findings. Lastly, a sum rule is derived that contains the CP phase delta^q and theta_C of the quark sector and the lepton mixing parameters theta_{13}, theta_{23} and delta.

    hep-phPRD(2019)·12 citations
33. 33*

    A novel approach to the computation of one-loop three- and four-point functions. III - The infrared divergent case

    J.Ph. Guillet (1)🇫🇷 · E. Pilon (1)🇫🇷 · Y. Shimizu (2)🇯🇵 · M. S. Zidi (3) ((1) Univ. Savoie Mont Blanc, CNRS, LAPTH, Annecy, France, (2) KEK, Tsukuba, Japan, (3) LPTh, Université de Jijel, Jijel, Algérie)🇩🇿

    This article is the third and last of a series presenting an alternative method to compute the one-loop scalar integrals. It extends the results of first two articles to the infrared divergent case. This novel method enjoys a couple of interesting features as compared with the methods found in the literature. It directly proceeds in terms of the quantities driving algebraic reduction methods. It yields a simple decision tree based on the vanishing of internal masses and one-pinched kinematic matrices which avoids a profusion of cases. Lastly, it extends to kinematics more general than the one of physical e.g. collider processes relevant at one loop. This last feature may be useful when considering the application of this method beyond one loop using generalised one-loop integrals as building blocks.

    hep-phPTEP(2020)·5 citations
34. 34*

    Anomalous transport phenomena and momentum space topology

    M.A.Zubkov🇮🇱 · Z.V.Khaidukov🇷🇺

    Using the derivative expansion applied to the Wigner transform of the two - point Green function this is possible to derive the response of various nondissipative currents to the external gauge fields. The corresponding currents are proportional to the momentum space topological invariants. This allows to analyse systematically various anomalous transport phenomena including the anomalous quantum Hall effect and the chiral separation effect. We discuss the application of this methodology both to the solid state physics and to the high energy physics.

    hep-phcond-mat.mes-hallEPJ Web Conf.(2018)·4 citations
35. 35*

    Fermion Pair Production in SO(5) x U(1) Gauge-Higgs Unification Models

    Jongmin Yoon🇺🇸 · Michael E. Peskin🇺🇸

    We compute fermion pair production cross sections in $e^{+}{e}^{-}$ annihilation in models of electroweak symmetry breaking in warped 5-dimensional space. Our analysis is based on a framework with no elementary scalars, only gauge bosons and fermions in the bulk. We apply a novel Green's function method to obtain an analytic understanding of the new physics effects across the parameter space. We present results for $e^{+}{e}^{-}\to b\bar{b}$ and $e^{+}{e}^{-}\to t\bar{t}$. The predicted effects will be visible in precision measurements. Different models of $b$ quark mass generation can be distinguished by these measurements already at 250 GeV in the center of mass.

    hep-ph28 citations
36. 36*

    Three-loop formula for quark and gluon contributions to the QCD trace anomaly

    Kazuhiro Tanaka (Juntendo Univ.)🇯🇵

    In the QCD energy-momentum tensor $T^{\mu \nu }$, the terms that contribute to physical matrix elements are expressed as the sum of the gauge-invariant quark part and gluon part. Each part undergoes the renormalization due to the interactions among quarks and gluons, although the total tensor $T^{\mu \nu }$ is not renormalized thanks to the conservation of energy and momentum. Recently it has been shown that, through the renormalization, each of the quark and gluon parts of $T^{\mu \nu }$ receives a definite amount of anomalous trace contribution, such that their sum reproduces the well-known QCD trace anomaly, $T_{\mu }^{\mu }=(\beta /2g)F^{\mu \nu }{F}_{\mu \nu }+m(1+{\gamma }_m)\bar{\psi }\psi$, and the corresponding formulas have been derived up to two-loop order. We extend this result to the three-loop order, working out all the relevant three-loop renormalization structure for the quark and gluon energy-momentum tensors in the (modified) minimal subtraction scheme in the dimensional regularization. We apply our three-loop formula of the quark/gluon decomposition of the trace anomaly to calculate the anomaly-induced mass structure of nucleons as well as pions.

    hep-phhep-exnucl-exnucl-thJHEP(2019)·49 citations
37. 37*

    Hearing the echoes of dark matter and new physics

    Fa Peng Huang🇰🇷

    Motivated by the absence of dark matter signal in dark matter direct detection experiments and new physics signal at LHC, we study how to hear the echoes of the new physics, especially the dark matter and baryogenesis by new approaches, such as the gravitational wave experiments.

    hep-phPoS(2019)·1 citation
38. 38*

    Higgs stability-bound and fermionic dark matter

    Aaron Held🇩🇪 · René Sondenheimer🇩🇪

    Higgs-portal interactions of fermionic dark matter -- in contrast to fermions coupled via Yukawa interactions -- can have a stabilizing effect on the standard-model Higgs potential. A non-perturbative renormalization-group analysis reveals that, similar to higher-order operators in the Higgs potential itself, the fermionic portal coupling can increase the metastability scale by only about one order of magnitude. Furthermore, this regime of very weakly coupled dark matter is in conflict with relic-density constraints. Conversely, fermionic dark matter with the right relic abundance requires either a low cutoff scale of the effective field theory or a strongly interacting scalar sector. This results in a triviality problem in the scalar sector which persists at the non-perturbative level. The corresponding breakdown of the effective field theory suggests a larger dark sector to be present not too far above the dark-fermion mass-scale.

    hep-phhep-thJHEP(2019)·21 citations
39. 39*

    Inclusive heavy flavor jet production with semi-inclusive jet functions: from proton to heavy-ion collisions

    Hai Tao Li🇺🇸 · Ivan Vitev🇺🇸

    The past several years have witnessed important developments in the QCD theory of jet production and jet substructure in hadronic collisions. In the framework of soft-collinear effective theory, semi-inclusive jet functions and semi-inclusive fragmenting jet functions have allowed us to combine higher order calculations with resummation of potentially large logarithms of the jet radius, $\ln R$. Very recently, the semi-inclusive jet functions for partons fragmenting into heavy flavor jets were computed by Dai, Kim and Leibovich. In this paper we show how the formalism can be extended to c-jet and b-jet production in heavy ion collisions. The semi-inclusive jet functions for heavy flavor jets in a QCD medium are evaluated up to the next-to-leading order in ${\alpha }_s$ and first order in opacity. For phenomenological applications, we also consider the inclusion of the cold nuclear matter effects and the jet energy dissipation due to collisional interactions in matter. We present the numerical predictions for the cross sections and the corresponding nuclear modification factors in proton-nucleus and nucleus-nucleus collisions and compare our results to data from the Large Hadron Collider.

    hep-phhep-exJHEP(2019)·54 citations
40. 40*

    Vector-Boson Fusion Higgs Pair Production at N${}^3$LO

    Frédéric A. Dreyer🇬🇧 · Alexander Karlberg🇨🇭

    We calculate the next-to-next-to-next-to-leading order (N${}^3$LO) QCD corrections to vector-boson fusion (VBF) Higgs pair production in the limit in which there is no partonic exchange between the two protons. We show that the inclusive cross section receives negligible corrections at this order, while the scale variation uncertainties are reduced by a factor four. We present differential distributions for the transverse momentum and rapidity of the final state Higgs bosons, and show that there is almost no kinematic dependence to the third order corrections. Finally we study the impact of deviations from the Standard Model in the trilinear Higgs coupling, and show that the structure of the higher order corrections does not depend on the self-coupling. These results are implemented in the latest release of the proVBFH-incl program.

    hep-phhep-exPRD(2018)·232 citations
41. 41*

    SO(10) paths to dark matter

    Sacha Ferrari🇧🇪 · Thomas Hambye🇧🇪 · Julian Heeck🇧🇪 · Michel H.G. Tytgat🇧🇪

    The grand-unification gauge group SO(10) contains matter parity as a discrete subgroup. This symmetry could be at the origin of dark matter stability. The properties of the dark matter candidates depend on the path along which SO(10) is broken, in particular through Pati-Salam or left-right symmetric subgroups. We systematically determine the non-supersymmetric dark matter scenarios that can be realized along the various paths. We emphasize that the dark matter candidates may have colored or electrically charged partners at low scale that belong to the same SO(10) multiplet. These states, which in many cases are important for co-annihilation, could be observed more easily than the dark matter particle. We determine the structure of the tree-level and loop-induced mass splittings between the dark matter candidate and their partners and discuss the possible phenomenological implications.

    hep-phhep-exPRD(2019)·39 citations
42. 42*

    Developing the MeV potential of DUNE: Detailed considerations of muon-induced spallation and other backgrounds

    Guanying Zhu (Ohio State)🇺🇸 · Shirley Weishi Li (Ohio State & SLAC)🇺🇸 · John F. Beacom (Ohio State)🇺🇸

    The Deep Underground Neutrino Experiment (DUNE) could be revolutionary for MeV neutrino astrophysics, because of its huge detector volume, unique event reconstruction capabilities, and excellent sensitivity to the ${\nu }_e$ flavor. However, its backgrounds are not yet known. A major background is expected due to muon spallation of argon, which produces unstable isotopes that later beta decay. We present the first comprehensive study of MeV spallation backgrounds in argon, detailing isotope production mechanisms and decay properties, analyzing beta energy and time distributions, and proposing experimental cuts. We show that above a nominal detection threshold of 5-MeV electron energy, the most important backgrounds are --- surprisingly --- due to low-A isotopes, such as Li, Be, and B, even though high-A isotopes near argon are abundantly produced. We show that spallation backgrounds can be powerfully rejected by simple cuts, with clear paths for improvements. We compare these background rates to rates of possible MeV astrophysical neutrino signals in DUNE, including solar neutrinos (detailed in a companion paper [Capozzi et al. arXiv:1808.08232 [hep-ph]]), supernova burst neutrinos, and the diffuse supernova neutrino background. Further, to aid trigger strategies, in the Appendixes we quantify the rates of single and multiple MeV events due to spallation, radiogenic neutron capture, and other backgrounds, including through pileup. Our overall conclusion is that DUNE has high potential for MeV neutrino astrophysics, but reaching this potential requires new experimental initiatives.

    hep-phastro-ph.HEnucl-thPRC(2019)·61 citations
43. 43*

    Fully differential Vector-Boson Fusion Higgs Pair Production at Next-to-Next-to-Leading Order

    Frédéric A. Dreyer🇬🇧 · Alexander Karlberg🇨🇭

    We calculate the fully differential next-to-next-to-leading order (NNLO) QCD corrections to vector-boson fusion (VBF) Higgs pair production. This calculation is achieved in the limit in which there is no colored cross-talk between the colliding protons, using the projection-to-Born method. We present differential cross sections of key observables, showing corrections of up to 3-4% at this order after typical VBF cuts, with the total cross section receiving contributions of about 2%. In contrast to single Higgs VBF production, we find that the NNLO corrections are for the most part within the next-to-leading order scale uncertainty bands.

    hep-phhep-exPRD(2019)·90 citations
44. 44*

    The Mono-Tau Menace: From $B$ Decays to High-$p_T$ Tails

    Admir Greljo🇨🇭 · Jorge Martin Camalich🇪🇸 · José David Ruiz-Álvarez🇨🇴

    We investigate the crossing-symmetry relation between $b\to c{\tau }^{-}\bar{\nu }$ decay and $b\bar{c}\to {\tau }^{-}\bar{\nu }$ scattering to derive direct correlations of New Physics in semi-tauonic $B$-meson decays and the mono-tau signature at the LHC ($pp\to {\tau }_{h}X$ + MET). Using an exhaustive set of effective operators and heavy mediators we find that the current ATLAS and CMS data constrain scenarios addressing anomalies in $B$-decays. Pure tensor solutions, completed by leptoquark, and right-handed solutions, completed by $W_R^{\prime }$ or leptoquark, are challenged by our analysis. Furthermore, the sensitivity that will be achieved in the high-luminosity phase of the LHC will probe $all$ the possible scenarios that explain the anomalies. Finally, we note that the LHC is also competitive in the $b\to u$ transitions and bounds in some cases are currently better than those from $B$ decays.

    hep-phhep-exPRL(2019)·138 citations
45. 45*

    Thermodynamics of a generalized graphene-motivated (2+1)-dimensional Gross-Neveu model beyond mean field within the Beth-Uhlenbeck approach

    D. Ebert🇩🇪 · D. Blaschke🇵🇱

    We investigate the thermodynamics at finite density of a generalized $(2+1)$-dimensional Gross-Neveu model of $N$ fermion species with various types of four-fermion interactions. The motivation for considering such a generalized schematic model arises from taking the Fierz-transformation of an effective Coulomb current-current interaction and certain symmetry breaking interaction terms, as considered for graphene-type models in Ref. [16]. We then apply path-integral bosonization techniques, based on the large $N$ limit, to derive the thermodynamic potential. This includes the leading order mean-field (saddle point) contribution as well as the next-order contribution of Gaussian fluctuations of exciton fields. The main focus of the paper is then the investigation of the thermodynamic properties of the resulting fermion-exciton plasma. In particular, we derive an extended Beth-Uhlenbeck form of the thermodynamic potential, discuss the Levinson theorem and the decomposition of the phase of the exciton correlation into a resonant and scattering part.

    ↳ cond-mat.mes-hallhep-phhep-thPTEP(2019)·12 citations
46. 46*

    Abrupt changes of hydrothermal activity in a lava dome detected by combined seismic and muon monitoring

    Y. Le Gonidec🇫🇷 · M. Rosas-Carbajal🇫🇷 · J. de Bremond d'Ars🇫🇷 · B. Carlus🇫🇷 · J.-C. Ianigro🇫🇷 · B. Kergosien🇫🇷 · J. Marteau🇫🇷 · D. Gibert🇫🇷

    The recent 2014 eruption of the Ontake volcano in Japan recalled that hydrothermal fields of moderately active volcanoes have an unpredictable and hazardous behavior that may endanger human beings. Steam blasts can expel devastating ejecta and create craters of several tens of meters. The management of such hydrothermal hazards in populated areas is problematic because of their very short time constants. At present no precursory signal is clearly identified as a potential warning of imminent danger. Here we show how the combination of seismic noise monitoring and muon density tomography allows to detect, with an unprecedented space and time resolution, the increase of activity of a hydrothermal focus located 50 to 100 m below the summit of an active volcano, the La Soufrière of Guadeloupe, in the Lesser Antilles. The present study deals with hydrothermal activity events at timescales of few hours to few days. We show how the combination of those two methods improves the risk evaluation of short-term hazards and the localization of the involved volumes in the volcano. We anticipate that the deployment of networks of various sensors including temperature probes, seismic antennas and cosmic muon telescopes around such volcanoes could valuably contribute to early warning decisions.

    ↳ physics.geo-phhep-exhep-phSci.Rep.(2019)·9 citations
47. 47*

    Deconfinement of non-strange hadronic matter with nucleons and $\Delta$ baryons to quark matter in neutron stars

    Debashree Sen🇮🇳 · T.K. Jha🇮🇳

    We explore the possibility of formation of $\Delta$ baryons (1232 MeV) in neutron star matter in an effective chiral model within the relativistic mean-field framework. With variation in delta-meson couplings, consistent with the constraints imposed on them, the resulting equation of state is obtained and the neutron star properties are calculated for static and spherical configuration. Within the framework of our model the critical densities of formation of $\Delta$s and the properties of neutron stars are found to be very sensitive to the iso-vector coupling compared to the scalar or vector couplings. We revisit the $\Delta$ puzzle and look for the possibility of phase transition from non-strange hadronic matter (including nucleons and $\Delta$s) to deconfined quark matter, based on QCD theories. The resultant hybrid star configurations satisfy the observational constraints on mass from the most massive pulsars PSR J1614-2230 and PSR J0348+0432 in static condition obtained with the general hydrostatic equilibrium based on GTR. Our radius estimates are well within the limits imposed from observational analysis of QLMBXs. The obtained values of $R_{1.4}$ are in agreement with the recent bounds specified from the observation of gravitational wave (GW170817)from binary neutron star merger. The constraint on baryonic mass from study of binary system PSR J0737-3039 is also satisfied with our hybrid equation of state. \noindent{Keywords: Delta baryons, Quark matter, Phase transition, Equation of State, Neutron Stars, Hybrid Stars}

    ↳ nucl-thastro-ph.HEhep-phInt.J.Mod.Phys.D(2018)·12 citations
48. 48*

    A guide to light-cone PDFs from Lattice QCD: an overview of approaches, techniques and results

    Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸

    Within the theory of Quantum Chromodynamics (QCD), the rich structure of hadrons can be quantitatively characterized, among others, using a basis of universal non-perturbative functions: parton distribution functions (PDFs), generalized parton distributions (GPDs), transverse-momentum dependent distributions (TMDs) and distribution amplitudes (DAs). For more than half a century, there has been a joint experimental and theoretical effort to obtain these partonic functions. However, the complexity of the strong interactions has placed severe limitations, and first-principle results on the distributions was extracted mostly from their moments computed in Lattice QCD. Recently, breakthrough ideas changed the landscape and several approaches were proposed to access the distributions themselves on the lattice. In this paper, we review in considerable detail approaches directly related to partonic distributions. We highlight a recent idea proposed by X. Ji on extracting quasi-distributions that spawned renewed interest in the whole field and sparked the largest amount of numerical studies of Lattice QCD. We discuss theoretical and practical developments, including challenges that had to be overcome, with some yet to be handled. We also review numerical results, including a discussion based on evolving understanding of the underlying concepts and theoretical and practical progress. Particular attention is given to important aspects that validated the quasi-distribution approach, such as renormalization, matching to light-cone distributions and lattice techniques. In addition to a thorough discussion of quasi-distributions, we consider other approaches: hadronic tensor, auxiliary quark methods, pseudo-PDFs, OPE without OPE and good lattice cross sections. In closing, we provide prospects of the field, with emphasis on the necessary conditions to obtain results with controlled uncertainties.

    ↳ hep-lathep-exhep-phAdv.High Energy Phys.(2019)·259 citations
49. 49*

    Nucleon form factors and root-mean-square radii on a (10.8 fm${)}^4$ lattice at the physical point

    Eigo Shintani🇯🇵 · Ken-Ichi Ishikawa🇯🇵 · Yoshinobu Kuramashi🇯🇵 · Shoichi Sasaki🇯🇵 · Takeshi Yamazaki🇯🇵

    We present the nucleon form factors and root-mean-square (RMS) radii measured on a (10.8 fm${)}^4$ lattice at the physical point. We compute the form factors at small momentum transfer region in $q^2\le 0.102$ GeV${}^2$ with the standard plateau method choosing four source-sink separation times $t_{\mathrm{sep}}$ from 0.84 to 1.35 fm to examine the possible excited state contamination. We obtain the electric and magnetic form factors and their RMS radii for not only the isovector channel but also the proton and neutron ones without the disconnected diagram. We also obtain the axial-vector coupling and the axial radius from the axial-vector form factor. We find that these three form factors do not show large $t_{\mathrm{sep}}$ dependence in our lattice setup. On the other hand, the induced pseudoscalar and pseudoscalar form factors show the clear effects of the excited state contamination, which affect the generalized Goldberger-Treiman relation.

    ↳ hep-lathep-phnucl-exnucl-thPRD(2019)·132 citations
50. 50*

    Effects of hadron-quark phase transition on properties of Neutron Stars

    Debashree Sen🇮🇳 · T.K. Jha🇮🇳

    We investigate the possible scenario of deconfinement of hyperon rich hadronic matter to quark matter at high densities and the resulting hybrid star (HS) properties are analyzed. In the relativistic mean-field framework, we construct the equation of state (EoS) of hadronic matter using the effective chiral model while the pure quark matter is described using the MIT Bag model. We revisit the hyperon puzzle and analyze the possibility of hadron-quark phase transition with proper choice of the bag constant. In static condition the maximum mass of the resultant HSs are in good agreement with the recent observational bounds on the same from high mass pulsars such as PSR J1614-2230 and PSR J0348+0432. On invoking the phenomenon of phase transition, the radius of canonical mass ($R_{1.4}$) and value of $R_{1.6}$ predicted by the model lie within the range prescribed from binary neutron star (BNS) merger detected by the LIGO-Virgo collaboration in 2017. The surface redshift obtained for the HSs also satisfy the constraints from pulsars RX J0720.4-3125 and 1E 1207.4-5209. It is noteworthy that unlike several other works, we add no modifications to the original form of the Bag model to satisfy these recent observational and empirical constraints on NS properties. We also discuss the rotational aspects of the HSs by calculating the properties like rotational mass, radius, energy density, moment of inertia at different angular velocities. The maximum bound on rotational frequency from the rapidly rotating pulsars like PSR B1937+21 and PSR J1748-2446ad are satisfied with the HS configuration. We also test the universality of our hybrid EoS in terms of normalized moment of inertia.

    ↳ nucl-thastro-ph.HEhep-phJ.Phys.G(2019)·25 citations
51. 51*

    Constraints on massive vector dark energy models from integrated Sachs-Wolfe-galaxy cross-correlations

    Shintaro Nakamura🇯🇵 · Antonio De Felice🇯🇵 · Ryotaro Kase🇯🇵 · Shinji Tsujikawa🇯🇵

    The gravitational-wave event GW170817, together with the electromagnetic counterpart, shows that the speed of tensor perturbations $c_T$ on the cosmological background is very close to that of light $c$ for the redshift $z<0.009$. In generalized Proca theories, the Lagrangians compatible with the condition $c_T=c$ are constrained to be derivative interactions up to cubic order, besides those corresponding to intrinsic vector modes. We place observational constraints on a dark energy model in cubic-order generalized Proca theories with intrinsic vector modes by running the Markov chain Monte Carlo (MCMC) code. We use the cross-correlation data of the integrated Sachs-Wolfe (ISW) signal and galaxy distributions in addition to the data sets of cosmic microwave background, baryon acoustic oscillations, type Ia supernovae, local measurements of the Hubble expansion rate, and redshift-space distortions. We show that, unlike cubic-order scalar-tensor theories, the existence of intrinsic vector modes allows the possibility for evading the ISW-galaxy anticorrelation incompatible with the current observational data. As a result, we find that the dark energy model in cubic-order generalized Proca theories exhibits a better fit to the data than the cosmological constant, even by including the ISW-galaxy correlation data in the MCMC analysis.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2019)·35 citations
52. 52*

    Quarkonium dissociation in perturbative QCD

    Juhee Hong🇰🇷 · Su Houng Lee🇰🇷

    For weakly bound quarkonia, we rederive the next-to-leading order cross sections of quarkonium dissociation by partons that include the hard thermal loop (HTL) resummation. Our results calculated with an effective vertex from the Bethe-Salpeter amplitude reduce to those obtained by potential nonrelativistic QCD (pNRQCD) in the relevant kinematical limit, and they can be used in a wide temperature range applicable to heavy quark systems in heavy ion collisions. Based on the lattice computation of the temperature-dependent binding energy, our numerical analysis on ${\rm Y}(1S)$ indicates that at high temperature the dominant mechanism for quarkonium dissociation is inelastic parton scattering as expected in the quasifree approximation, while it is the gluo-dissociation at low temperature. By comparing with the momentum diffusion coefficient of a heavy quark, we discuss possible O(g) corrections to the next-to-leading order thermal width.

    ↳ nucl-thhep-phPRC(2019)·8 citations
53. 53*

    Deep-inelastic and quasielastic electron scattering from $A=3$ nuclei

    A. J. Tropiano🇺🇸 · J. J. Ethier🇳🇱 · W. Melnitchouk🇺🇸 · N. Sato🇺🇸

    We perform a combined analysis of inclusive electron scattering data from $A=3$ nuclei in the deep-inelastic and quasielastic scattering regions, using Monte Carlo analysis methods and the nuclear weak binding approximation to establish the range over which the data can be described within the same theoretical framework. Comparison with quasielastic ${}^3$He cross sections from SLAC and Jefferson Lab suggests that most features of the $x\gtrsim 1$ data can be reasonably well described in the impulse approximation with finite-$Q^2$ nuclear smearing functions for momentum transfers $Q^2\gtrsim 1$ GeV${}^2$. For the DIS region, we analyze the recent ${}^3$He to deuterium cross section ratio from the Jefferson Lab E03-103 experiment to explore the possible isospin dependence of the nuclear effects. We discuss the implications of this for the MARATHON experiment at Jefferson Lab, and outline how a Bayesian analysis of ${}^3$He, ${}^3$H and deuterium data can robustly determine the free neutron structure function.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2019)·19 citations
54. 54*

    Simplification of tensor expressions in computer algebra

    A.Kryukov🇷🇺 · G.Shpiz🇷🇺

    Computer algebra is widely used in various fields of mathematics, physics and other sciences. The simplification of tensor expressions is an important special case of computer algebra. In this paper, we consider the reduction of tensor polynomials to canonical form, taking into account the properties of symmetry under permutations of indices, the symmetries associated with the renaming of summation indices, and also linear relations between tensors of a general form. We give a definition of the canonical representation for polynomial (multiplicative) expressions of variables with abstract indices, which is the result of averaging of the original expression by the action of some finite group (the signature stabilizer). In practice, the proposed algorithms demonstrate high efficiency for expressions made of Riemann curvature tensors.

    ↳ cs.SChep-phhep-thJ.Phys.Conf.Ser.(2019)·1 citation
55. 55*

    Elucidating the multiplicity dependence of J/$\psi$ production in proton-proton collisions with PYTHIA8

    S. G. Weber🇩🇪 · A. Dubla🇩🇪 · A. Andronic🇩🇪 · A. Morsch🇨🇭

    A study of prompt and non-prompt J/$\psi$ production as a function of charged-particle multiplicity in inelastic proton--proton (pp) collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV based on calculations using the PYTHIA8 Monte Carlo is reported. Recent experimental data shows an intriguing stronger-than-linear increase of the self-normalized J/$\psi$ yield with multiplicity; several models, based on initial or final state effects, have been able to describe the observed behaviour. In this paper, the microscopic reasons for this behaviour, like the role of multiple parton interactions, colour reconnections and auto-correlations are investigated. It is observed that the stronger-than-linear increase and the transverse momentum ($p_{\mathrm{T}}$) dependence, contrary to what is predicted by the other available models, can be attributed to auto-correlation effects only. In absence of auto-correlation effects, the increase of the yield of J/$\psi$ with multiplicity -- and in general for all hard processes -- is weaker than linear for multiplicities exceeding about three times the mean multiplicity. The possibility of disentangling auto-correlation effects from other physical phenomena by measuring the charged-particle multiplicity in different pseudo-rapidity and azimuthal regions relative to the J/$\psi$ direction is investigated. In this regard, it is suggested to extend the experimental measurements of J/$\psi$ production as a function of the charged-particle multiplicity by determining the multiplicity in several azimuthal regions and in particular in the Transverse region with respect to the direction of the J/$\psi$ meson.

    ↳ nucl-thhep-phnucl-exEPJC(2019)·61 citations
56. 56*

    Constraints on Hořava gravity from binary black hole observations

    Oscar Ramos🇫🇷 · Enrico Barausse🇫🇷

    Hořava gravity breaks Lorentz symmetry by introducing a preferred spacetime foliation, which is defined by a timelike dynamical scalar field, the khronon. The presence of this preferred foliation makes black hole solutions more complicated than in General Relativity, with the appearance of multiple distinct event horizons: a matter horizon for light/matter fields, a spin-0 horizon for the scalar excitations of the khronon, a spin-2 horizon for tensorial gravitational waves, and even, at least in spherical symmetry, a universal horizon for instantaneously propagating modes appearing in the ultraviolet. We study how black hole solutions in Hořava gravity change when the black hole is allowed to move with low velocity relative to the preferred foliation. These slowly moving solutions are a crucial ingredient to compute black hole "sensitivities" and predict gravitational wave emission (and in particular dipolar radiation) from the inspiral of binary black hole systems. We find that for generic values of the theory's three dimensionless coupling constants, slowly moving black holes present curvature singularities at the universal horizon. Singularities at the spin-0 horizon also arise unless one waives the requirement of asymptotic flatness at spatial infinity. Nevertheless, we have verified that at least in a one-dimensional subset of the (three-dimensional) parameter space of the theory's coupling constants, slowly moving black holes are regular everywhere, even though they coincide with the general relativistic ones (thus implying in particular the absence of dipolar gravitational radiation). Remarkably, this subset of the parameter space essentially coincides with the one selected by the recent constraints from GW170817 and by solar system tests.

    ↳ gr-qchep-phhep-thPRD(2019)·60 citations
57. 57*

    Axion-like Dark Matter Constraints from CMB Birefringence

    Günter Sigl🇩🇪 · Pranjal Trivedi🇮🇳

    Axion-like particles are dark matter candidates motivated by the Peccei-Quinn mechanism and also occur in effective field theories where their masses and photon couplings are independent. We estimate the dispersion of circularly polarized photons in a background of oscillating axion-like particles (ALPs) with the standard $g_{a\gamma }a{F}_{\mu \nu }{\tilde{F}}^{\mu \nu }/4$ coupling to photons. This leads to birefringence or rotation of linear polarization by ALP dark matter. Cosmic microwave background (CMB) birefringence limits $\Delta \alpha \lesssim (1.0{)}^{\circ }$ enable us to constrain the axion-photon coupling $g_{a\gamma }\lesssim 10^{-17}-10^{-12}{\mathrm{GeV}}^{-1}$, for ultra-light ALP masses $m_a\sim 10^{-27}-10^{-24}$ eV. This improves upon previous axion-photon coupling limits by up to four orders of magnitude. Future CMB observations could tighten limits by another one to two orders.

    ↳ astro-ph.COhep-ph55 citations
58. 58*

    Anisotropic stars as ultracompact objects in General Relativity

    Guilherme Raposo🇮🇹 · Paolo Pani🇮🇹 · Miguel Bezares🇪🇸 · Carlos Palenzuela🇪🇸 · Vitor Cardoso🇵🇹

    Anisotropic stresses are ubiquitous in nature, but their modeling in General Relativity is poorly understood and frame dependent. We introduce the first study on the dynamical properties of anisotropic self-gravitating fluids in a covariant framework. Our description is particularly useful in the context of tests of the black hole paradigm, wherein ultracompact objects are used as black hole mimickers but otherwise lack a proper theoretical framework. We show that: (i) anisotropic stars can be as compact and as massive as black holes, even for very small anisotropy parameters; (ii) the nonlinear dynamics of the 1+1 system is in good agreement with linearized calculations, and shows that configurations below the maximum mass are nonlinearly stable; (iii) strongly anisotropic stars have vanishing tidal Love numbers in the black-hole limit; (iv) their formation will usually be accompanied by gravitational-wave echoes at late times.

    ↳ gr-qcastro-ph.HEhep-phPRD(2019)·205 citations
59. 59*

    Emergent photons and gravitons

    J.L. Chkareuli🇬🇪 · J. Jejelava🇬🇪 · Z. Kepuladze🇬🇪

    Now, it is already not a big surprise that due to the spontaneous Lorentz invariance violation (SLIV) there may emerge massless vector and tensor Goldstone modes identified particularly with photon and graviton. Point is, however, that this mechanism is usually considered separately for photon and graviton, though in reality they appear in fact together. In this connection, we recently develop the common emergent electrogravity model which would like to present here. This model incorporates the ordinary QED and tensor field gravity mimicking linearized general relativity. The SLIV is induced by length-fixing constraints put on the vector and tensor fields, $A_{\mu }^2=\pm M_A^2$ and $H_{\mu \nu }^2=\pm M_H^2$ ($M_A$ and $M_H$ are the proposed symmetry breaking scales) which possess the much higher symmetry then the model Lagrangian itself. As a result, the twelve Goldstone modes are produced in total and they are collected into the vector and tensor field multiplets. While photon is always the true vector Goldstone boson, graviton contain pseudo-Goldstone modes as well. In terms of the appearing zero modes, theory becomes essentially nonlinear and contains many Lorentz and CPT violating interaction. However, as argued, they do not contribute in processes which might lead to the physical Lorentz violation. Nonetheless, how the emergent electrogravity theory could be observationally differed from conventional QED and GR theories is also briefly discussed.

    ↳ physics.gen-phhep-phhep-thBled Workshops Phys.(2018)·5 citations
60. 60*

    Heterotic M-Theory from the Clockwork Perspective

    Sang Hui Im🇰🇷 · Hans Peter Nilles🇩🇪 · Marek Olechowski🇵🇱

    Compactifications of heterotic M-theory are shown to provide solutions to the weak- and axion-scale hierarchy problems as a consequence of warped large extra dimensions. They allow a description that is reminiscent of the so-called continuous clockwork mechanism. The models constructed here cover a new region of clockwork parameter space and exhibit unexplored spectra and couplings of Kaluza-Klein modes. Previously discussed models are outside this region of parameter space and do seem to require an ultraviolet completion other than that of perturbative higher dimensional $D=10,11$ string- or M-theory. A 5D-supergravity description can be given for all explicitly known continuous clockwork models. The various classes of models can be distinguished through the different roles played by vector multiplets and the universal hypermultiplet in 5D-supergravity.

    ↳ hep-thhep-phJHEP(2019)·8 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.