Tue·Jan 28, 2020Tuesday·January 28, 2020

1. 01*

   Quantum decoherence and relaxation in long-baseline neutrino data

   A. L. G. Gomes🇧🇷 · R. A. Gomes🇧🇷 · O. L. G. Peres🇧🇷

   We investigate the effect of quantum decoherence and relaxation in neutrino oscillations using MINOS and T2K data. The formalism of open quantum systems is used to describe the interaction of a neutrino system with the environment, where the strength of the interaction is regulated by a decoherence parameter $\Gamma$. We assume an energy dependence parameterized by $\Gamma ={\gamma }_0(E/\text{mbox}GeV{)}^n$, with $n=-2,0,+2$, and consider three different scenarios, allowing the investigation of the effect of relaxation and of constraining the solar and atmospheric sectors to the same decoherence parameter. The MINOS and T2K data present a complementary behavior, with regard to our theoretical model, resulting in a better sensitivity for $n=+2$ and $n=-2$, respectively. We perform a combined analyses of both experimental data, which also include a reactor constraint on ${\sin }^2{\theta }_{13}$, and observe an independence of the results to the scenarios we investigate. As highlight of our analyses we obtain the best limit on ${\gamma }_0$ for the energy dependence of $n=-2$, reporting an upper bound of $1.7\times 10^{-23}$~GeV, at the 90\% confidence level.

   hep-phJHEP(2023)·37 citations
2. 02*

   LHC signals of triplet scalars as dark matter portal: cut-based approach and improvement with gradient boosting and neural networks

   Atri Dey🇮🇳 · Jayita Lahiri🇮🇳 · Biswarup Mukhopadhyaya🇮🇳

   We consider a scenario where an SU(2) triplet scalar acts as the portal for a scalar dark matter particle. We identify regions of the parameter space, where such a triplet coexists with the usual Higgs doublet consistently with all theoretical as well as neutrino, accelerator and dark matter constraints, and the triplet-dominated neutral state has substantial invisible branching fraction. LHC signals are investigated for such regions, in the final state {\em same-sign dilepton + $\ge$ 2 jets + $/E_T$.} While straightforward detectability at the high-luminosity run is predicted for some benchmark points in a cut-based analysis, there are other benchmarks where one has to resort to gradient boosting/neural network techniques in order to achieve appreciable signal significance.

   hep-phJHEP(2020)·12 citations
3. 03*

   Properties of $Z_c(3900)$ tetraquark in a cold nuclear matter

   K. Azizi🇮🇷 · N. Er🇹🇷

   The study of medium effects on properties of particles embedded in nuclear matter is of great importance for understanding the nature and internal quark-gluon organization as well as exact determination of the quantum numbers, especially of the exotic states. In this context, we study the physical properties of one of the famous charmonium-like states, $Z_c(3900)$, in a cold dense matter. We investigate the possible shifts in the mass and current-meson coupling of the $Z_c(3900)$ state due to the dense medium at saturation density, ${\rho }^{sat}$, by means of the in-medium sum rules. We also estimate the vector self-energy of this state at saturation nuclear matter density. We discuss the behavior of the spectroscopic parameters of this state with respect to the density up to a high density corresponding to the core of neutron stars, $\rho \approx 5{\rho }^{sat}$. Both the mass and current-coupling of this state show nonlinear behavior and decrease with respect to the density of the medium: the mass reaches roughly $30\%$ of its vacuum value at $\rho =5{\rho }^{sat}$, while the current-coupling approaches zero at $\rho \approx 2.1{\rho }^{sat}$, when the central values of the auxiliary and other input parameters are used.

   hep-phhep-exhep-latPRD(2020)·11 citations
4. 04*

   A self-consistent framework of topological amplitude and its $SU(N)$ decomposition

   Di Wang🇨🇳 · Cai-Ping Jia🇨🇳 · Fu-Sheng Yu🇨🇳

   We propose a systematic theoretical framework for the topological amplitudes of the heavy meson decays and their $SU(N)$ decomposition. In the framework, the topological amplitudes are expressed in invariant tensors and classified into tree- and penguin-operator-induced diagrams according to which four-quark operators, tree or penguin, being inserted into their effective weak vertexes. By decomposing the four-quark operators into irreducible representations of $SU(N)$ group, one can derive the $SU(N)$ irreducible amplitudes from the tensor form of the topology. Taking the $D\to PP$ decay ($P$ denoting a pseudoscalar meson) with $SU(3{)}_F$ symmetry as an example, we show our framework in detail. The fact that some topologies are not independent in the $SU(3{)}_F$ limit is explained by group theory. It is found that there are only nine independent topologies in all tree- and penguin-operator-induced diagrams contributing to the $D\to PP$ decays in the Standard Model. If a large quark-loop diagram is assumed, the large $\Delta A_{CP}$ and the very different $D^0\to K^{+}{K}^{-}$ and $D^0\to {\pi }^{+}{\pi }^{-}$ branching fractions can be explained with a normal $U$-spin breaking. Moreover, our framework provides a simple and systematic way to analyze the $SU(N)$ breaking effects. As examples, the linear $SU(3{)}_F$ breaking and the high order $U$-spin breaking in charm decays are re-investigated in our framework, which are consistent with literature. We propose the concepts of splitting and degeneracy of topologies, and use them to describe the charm-less bottom decay. We find $SU(3{)}_F$ analysis for the charm-less $B$ decays is different from the $D$ decays because the charm-quark loop is beyond the $SU(3)$ symmetry and should be investigated in the symmetry breaking chain of $SU(4)\to SU(3)$.

   hep-phJHEP(2020)·39 citations
5. 05*

   Baryonia with open and hidden strange

   S.M. Gerasyuta🇷🇺 · E.E. Matskevich🇷🇺

   The relativistic six-quark equations are found in the framework of the dispersion relation technique. The strange baryonia are constructed without the mixing of the quarks and antiquarks. The relativistic six-quark amplitudes of the strange baryonia with the open and hidden strange are calculated. The poles of these amplitudes determine the masses of strange baryonia. 17 masses of baryonia are predicted.

   hep-phIJMPE(2020)·5 citations
6. 06*

   A comparative study of $0\nu \beta \beta$ decay in symmetric and asymmetric left-right model

   Chayan Majumdar🇮🇳 · Sudhanwa Patra🇮🇳 · Prativa Pritimita🇮🇳 · Supriya Senapati🇮🇳

   We study the new physics contributions to neutrinoless double beta decay ($0\nu \beta \beta$) in a TeV scale left-right model with spontaneous D-parity breaking mechanism where the values of the $SU(2{)}_L$ and $SU(2{)}_R$ gauge couplings, $g_L$ and $g_R$ are unequal. Neutrino mass is generated in the model via gauge extended inverse seesaw mechanism. We embed the model in a non-supersymmetric $SO(10)$ GUT with a purpose of quantifying the results due to the condition $g_L\ne g_R$. We compare the predicted numerical values of half life of $0\nu \beta \beta$ decay, effective Majorana mass parameter and other lepton number violating parameters for three different cases; (i) for manifest left-right symmetric model ($g_L=g_R$), (ii) for left-right model with spontaneous D parity breaking ($g_L\ne g_R$), (iii) for Pati-Salam symmetry with D parity breaking ($g_L\ne g_R$). We show how different contributions to $0\nu \beta \beta$ decay are suppressed or enhanced depending upon the values of the ratio $\frac{g_R}{g_L}$ that are predicted from successful gauge coupling unification.

   hep-phNPB(2020)·14 citations
7. 07*

   Decay properties of $P_c$ states through the Fierz rearrangement

   Hua-Xing Chen🇨🇳

   We systematically study hidden-charm pentaquark currents with the quark configurations $[\bar{c}u][udc]$, $[\bar{c}d][uuc]$, and $[\bar{c}c][uud]$. Some of their relations are derived using the Fierz rearrangement of the Dirac and color indices, and the obtained results are used to study strong decay properties of $P_c$ states as ${\bar{D}}^{(\ast )}{\Sigma }_c$ hadronic molecules. We calculate their relative branching ratios for the $J/\psi p$, ${\eta }_{c}p$, ${\chi }_{c0}p$, ${\chi }_{c1}p$, ${\bar{D}}^{(\ast )0}{\Lambda }_c^{+}$, ${\bar{D}}^0{\Sigma }_c^{+}$, and ${\bar{D}}^{-}{\Sigma }_c^{++}$ decay channels. We propose to search for the $P_c(4312)$ in the ${\eta }_{c}p$ channel and the $P_c(4440)/P_c(4457)$ in the ${\bar{D}}^0{\Lambda }_c^{+}$ channel.

   hep-phhep-exhep-latEPJC(2020)·27 citations
8. 08*

   Correspondence of multiplicity and energy distributions

   Maciej Rybczyński🇵🇱 · Zbigniew Włodarczyk🇵🇱

   The evaluation of the number of ways we can distribute energy among a collection of particles in a system is important in many branches of modern science. In particular, in multiparticle production processes the measurements of particle yields and kinematic distributions are essential for characterizing their global properties and to develop an understanding of the mechanism for particle production. We demonstrate that energy distributions are connected with multiplicity distributions by their generating functions.

   hep-phEPJA(2021)·3 citations
9. 09*

   Centrality criteria of inelastic nucleon-nucleon collisions

   Vladimir Komarov🇷🇺 · Bota Baimurzinova🇷🇺 · Ainur Kunsafina🇷🇺 · Dmitry Tsirkov🇷🇺

   A process of inelastic nucleon-nucleon collisions with the impact parameter less than a radius of the nucleon quark core is considered. The criteria for selection of such collisions from a full array of the nucleon-nucleon interactions are suggested.

   hep-phnucl-exnucl-th1 citation
10. 10*

    Anisotropic momentum broadening in the 2+1D Glasma: analytic weak field approximation and lattice simulations

    Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Daniel Schuh🇦🇹

    In heavy ion collisions, transverse momentum broadening quantifies the modification of a hard probe due to interactions with the quark-gluon plasma (QGP). We calculate momentum broadening in the Glasma, which is the highly non-isotropic precursor stage of the QGP right after the collision. We show that the Glasma leads to anisotropic momentum broadening: high energy partons accumulate more momentum along the beam axis than transverse to it. The physical origin of anisotropic broadening can be traced back to differences in the shapes of chromo-electric and chromo-magnetic flux tubes in the Glasma. We provide semi-analytic results for momentum broadening in the dilute Glasma and numerical results from real-time lattice simulations of the non-perturbative dense Glasma.

    hep-phhep-latnucl-thPRD(2020)·68 citations
11. 11*

    Charm CP: $\Delta A_{CP}$ and Radiative decays

    Amarjit Soni🇺🇸

    Motivated by the very important discovery of CP violation in charm-decays for the first time, by the LHCb collaboration, the role of nearby resonances such as the scalar $f_0(1710)$ in accounting for the observed CP is discussed. It is suggested that the influence of such a resonance may also explain the long-standing puzzle of such a large breaking of SU(3) seen in its decays. It is also explained that intervention of such resonance(s) will render first principles calculations of $\Delta A_{CP}$ rather difficult. Instead, it is proposed that searches for CP violation in simple radiative final states, such as $D^0\to \gamma \varphi [\to K^{+}{K}^{-}]$, $D^0\to l^{+}{l}^{-}\pi$ etc. has much better chance of theoretical precision studies and therefore theoretical and experimental investigations therein are strongly urged.

    hep-phPoS(2020)·7 citations
12. 12*

    On-shell heavy particle effective theories

    Rafael Aoude🇩🇪 · Kays Haddad🇩🇰 · Andreas Helset🇩🇰

    We introduce on-shell variables for Heavy Particle Effective Theories (HPETs) with the goal of extending Heavy Black Hole Effective Theory to higher spins and of facilitating its application to higher post-Minkowskian orders. These variables inherit the separation of spinless and spin-inclusive effects from the HPET fields, resulting in an explicit spin-multipole expansion of the three-point amplitude for any spin. By matching amplitudes expressed using the on-shell HPET variables to those derived from the one-particle effective action, we find that the spin-multipole expansion of a heavy spin-$s$ particle corresponds exactly to the multipole expansion (up to order $2s$) of a Kerr black hole, that is, without needing to take the infinite spin limit. Finally, we show that tree-level radiative processes with same-helicity bosons emitted from a heavy spin-$s$ particle exhibit a spin-multipole universality.

    ↳ hep-thgr-qchep-phJHEP(2020)·231 citations
13. 13*

    Phase diagram of the large $N$ Gross-Neveu model in a finite periodic box

    Rajamani Narayanan🇺🇸

    We analyze the Gross-Neveu model in the limit of large number of flavors of massless fermions. We study the phase diagram in a two and three dimensional periodic box at a fixed thermal to spatial aspect ratio, $\frac{\beta }{\ell }$, with a flavor independent chemical potential. We assume the bilinear condensate, when one exists, has a specific momentum in the spatial direction(s). The main known features of the phase diagram in the $\ell \to \infty$ limit of the two dimensional model are also seen on a finite $\ell \times \beta$ torus -- a phase with a homogeneous (zero momentum) condensate; a phase with an inhomogeneous (non-zero momentum) condensate and a phase with no condensate. We observe that the inhomogeneous phase contains several sub-phases characterized by a specific spatial momentum. Unlike the two dimensional model, we do not find evidence for a phase with a inhomogeneous condensate in the three dimensional model.

    ↳ hep-thhep-lathep-phPRD(2020)·28 citations
14. 14*

    Screening properties of quark-gluon plasma obtained from distribution and correlation functions of the constituent quasiparticle model

    V. Filinov🇷🇺 · A. Larkin🇷🇺 · V. Fortov🇷🇺

    Based on the constituent quasiparticle model of quark-gluon plasma (QGP), the matrix elements of the density operator and the Wigner function in the color phase space are presented in form of color path integrals over Wiener and SU(3) group Haar measures. Monte Carlo calculations of quark and gluon momentum distributions and spatial pair distribution functions have been carried out for the strongly coupled QGP plasma in thermal equilibrium at zero baryon chemical potential. The Debye screening mass and the running coupling constant have been obtained from the spatial pair distribution function and are in agreement with the available lattice QCD data. At densities related to the average interparticle distance more than 0.4 fm the gluon bound states in the form of glueballs have been found. Comparison with the Maxwell Boltzmann distribution shows significant influence of interparticle interaction on high energy asymptotics of the momentum distribution functions, resulting in appearance of quantum tails. The new color pair correlation function has been introduced, and related new color screening mass has been discussed.

    ↳ nucl-thhep-phPRC(2020)·0 citations
15. 15*

    Novel Perspectives in String Phenomenology

    Alon E Faraggi🇬🇧

    String theory is the leading contemporary framework to explore the synthesis of quantum mechanics with gravity. String phenomenology aims to study string theory while maintaining contact with observational data. The fermionic $Z_2\times Z_2$ orbifold provides a case study that yielded a rich space of phenomenological models. String theory in ten dimensions gives rise to non--supersymmetric tachyonic vacua that may serve as good starting points for the construction of phenomenologically viable models. I discuss an example of such a three generation standard--like model in which all the moduli, aside from the dilaton, are frozen. The Möbius symmetry may turn out to play a central role in the synthesis of quantum mechanics and gravity. In a local version it plays a central role in string theory. In a global version it underlies the Equivalence Postulate of Quantum Mechanics (EPOQM) formalism, which implies that spatial space is compact. It was recently proposed that evidence that the universe is closed exists in the Cosmic Microwave Background Radiation \cite{DiVMS}.

    ↳ hep-thhep-phPoS(2020)·1 citation
16. 16*

    Exploring the $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\Lambda }_c^{-}$ cross sections

    Yong Xie🇨🇳 · Zhiqing Liu🇨🇳

    A simultaneous fit is performed to the $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\Lambda }_c^{-}$ cross section data measured by Belle and BESIII from threshold up to 5.4 GeV. In order to accommodate both the BESIII measurement near threshold and the Belle observation of a resonance $Y(4630)$, we build a composite PDF with a Breit-Wigner resonance and a continuum contribution to model the full cross section line shape of $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\Lambda }_c^{-}$. The fit gives a mass of $M=[4636.1_{-7.2}^{+9.8}($stat$)\pm 8.0($syst$)]$~MeV/$c^2$, a width of ${\Gamma }_{\mathrm{tot}}=[34.5_{-16.2}^{+21.0}($stat$)\pm 5.6($syst$)]$~MeV, and ${\Gamma }_{e^{+}{e}^{-}}\mathcal{B}[Y(4630)\to {\Lambda }_c^{+}{\Lambda }_c^{-}]=[18.3_{-6.1}^{+8.8}($stat$)\pm 1.1($syst$)]$~eV/$c^2$ for the resonance. The width of $Y(4630)$ from our study is narrower than the previous Belle fit. The mass and width of $Y(4630)$ also show good agreement with a vector resonance $Y(4626)$ recently observed in $D_s^{+}{D}_{s1}(2536{)}^{-}$ by Belle.

    ↳ hep-exhep-ph4 citations
17. 17*

    The Generalized Hypergeometric Structure of the Ward Identities of CFT's in Momentum Space in $d>2$

    Claudio Corianò🇮🇹 · Matteo Maria Maglio🇮🇹

    We review the emergence of hypergeometric structures (of $F_4$ Appell functions) from the conformal Ward identities (CWIs) in conformal field theories (CFTs) in dimensions $d>2$. We illustrate the case of scalar 3- and 4-point functions. 3-point functions are associated to hypergeometric systems with 4 independent solutions. For symmetric correlators they can be expressed in terms of a single 3K integral - functions of quadratic ratios of momenta - which is a parametric integral of three modified Bessel $K$ functions. In the case of scalar 4-point functions, by requiring the correlator to be conformal invariant in coordinate space as well as in some dual variables (i.e. dual conformal invariant), its explicit expression is also given by a 3K integral, or as a linear combination of Appell functions which are now quartic ratios of momenta. Similar expressions have been obtained in the past in the computation of an infinite class of planar ladder (Feynman) diagrams in perturbation theory, which, however, do not share the same (dual conformal/conformal) symmetry of our solutions. We then discuss some hypergeometric functions of 3 variables, which define 8 particular solutions of the CWIs and correspond to Lauricella functions. They can also be combined in terms of 4K integral and appear in an asymptotic description of the scalar 4-point function, in special kinematical limits.

    ↳ hep-thhep-phmath-phmath.MPAxioms(2020)·13 citations
18. 18*

    Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive ${}^{222}$Ra and ${}^{228}$Ra Beams

    P.A. Butler🇬🇧 · L.P. Gaffney🇨🇭 · P. Spagnoletti🇬🇧 · K. Abrahams🇿🇦 · M. Bowry🇨🇦 · J. Cederkäll🇸🇪 · G. De Angelis🇮🇹 · H. De Witte🇧🇪 · P.E. Garrett🇨🇦 · A. Goldkuhle🇩🇪 · C. Henrich🇩🇪 · A. Illana🇮🇹 and 31 other authors

    There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in ${}^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing ${}^{222}$Ra as pear-shaped with stable octupole deformation, while ${}^{228}$Ra behaves like an octupole vibrator.

    ↳ nucl-exhep-phnucl-thphysics.atom-phPRL(2020)·94 citations
19. 19*

    The $a_0$ -- cosmology connection in MOND

    Mordehai Milgrom🇮🇱

    I limelight and review a potentially crucial aspect of MOND: The near equality of the MOND acceleration constant, $a_0$ -- as deduced from local, galactic phenomena -- and cosmological parameters. To wit, $a_0\sim c{H}_0\sim c^2{\Lambda }^{1/2}\sim c^2/{\ell }_U$, where $H_0$ is the present value of the Hubble-Lemaître constant, $\Lambda$ is the `cosmological constant', and ${\ell }_U$ is a cosmological characteristic length; e.g., the Hubble distance, or the de Sitter radius associated with $\Lambda$. In itself, this near equality has some important phenomenological consequences, such as the impossibility of black holes, and of cosmological strong lensing, in the MOND regime. More importantly perhaps, this `coincidence' may be a pointer to the `FUNDAMOND' -- the more basic theory underlying MOND phenomenology. The manners in which such a relation emerges in existing, underlying scheme of MOND are also reviewed, interlaced with examples of similar relations in other physical systems, between apparently-fundamental velocity, length, and acceleration constants. Such analogies may point the way to explanation of the MOND `coincidence'.

    ↳ astro-ph.GAgr-qchep-ph27 citations
20. 20*

    Bulk properties and multi-particle correlations in large and small systems

    Bjoern Schenke🇺🇸 · Chun Shen🇺🇸 · Prithwish Tribedy🇺🇸

    Charged particle production is calculated in a hybrid framework consisting of the IP-Glasma initial state, MUSIC viscous relativistic fluid dynamics, and the UrQMD microscopic hadronic cascade. Using one set of parameters, we compute observables for a large variety of collision systems. We compare to experimental data in p+p, p+Pb, Xe+Xe, Au+Au and Pb+Pb collisions at various energies, and make predictions for potential O+O runs at RHIC and LHC.

    ↳ nucl-thhep-phnucl-exNPA(2021)·10 citations
21. 21*

    Contribution of pulsars to cosmic-ray positrons in light of recent observation of inverse-Compton halos

    Silvia Manconi🇩🇪 · Mattia Di Mauro🇺🇸 · Fiorenza Donato🇮🇹

    The hypothesis that pulsar wind nebulae (PWNe) can significantly contribute to the excess of the positron ($e^{+}$) cosmic-ray flux has been consolidated after the observation of a $\gamma$-ray emission at TeV energies of a few degree size around Geminga and Monogem PWNe, and at GeV energies for Geminga at a much larger extension. The $\gamma$-ray halos around these PWNe are interpreted as due to electrons ($e^{-}$) and $e^{+}$ accelerated and escaped by their PWNe, and inverse Compton scattering low-energy photons of the interstellar radiation fields. The extension of these halos suggests that the diffusion around these PWNe is suppressed by two orders of magnitude with respect to the average in the Galaxy. We implement a two-zone diffusion model for the propagation of $e^{+}$ accelerated by the Galactic population of PWNe. We consider pulsars from the ATNF catalog and build up simulations of the PWN Galactic population. In both scenarios, we find that within a two-zone diffusion model, the total contribution from PWNe and secondary $e^{+}$ is at the level of AMS-02 data, for an efficiency of conversion of the pulsar spin down energy in $e^{\pm }$ of $\eta \sim 0.1$. For the simulated PWNe, a $1\sigma$ uncertainty band is determined, which is of at least one order of magnitude from 10 GeV up to few TeV. The hint for a decreasing $e^{+}$ flux at TeV energies is found, even if it is strongly connected to the chosen value of the radius of the low diffusion bubble around each source.

    ↳ astro-ph.HEhep-phPRD(2020)·69 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.