Tue·Mar 7, 2017Tuesday·March 7, 2017

1. 01*

   SCYNet: Testing supersymmetric models at the LHC with neural networks

   Philip Bechtle🇩🇪 · Sebastian Belkner🇩🇪 · Daniel Dercks🇩🇪 · Matthias Hamer🇩🇪 · Tim Keller🇩🇪 · Michael Krämer🇩🇪 · Björn Sarrazin🇩🇪 · Jan Schütte-Engel🇩🇪 · Jamie Tattersall🇩🇪

   SCYNet (SUSY Calculating Yield Net) is a tool for testing supersymmetric models against LHC data. It uses neural network regression for a fast evaluation of the profile likelihood ratio. Two neural network approaches have been developed: one network has been trained using the parameters of the 11-dimensional phenomenological Minimal Supersymmetric Standard Model (pMSSM-11) as an input and evaluates the corresponding profile likelihood ratio within milliseconds. It can thus be used in global pMSSM-11 fits without time penalty. In the second approach, the neural network has been trained using model-independent signature-related objects, such as energies and particle multiplicities, which were estimated from the parameters of a given new physics model. While the calculation of the energies and particle multiplicities takes up computation time, the corresponding neural network is more general and can be used to predict the LHC profile likelihood ratio for a wider class of new physics models.

   hep-phhep-exEPJC(2017)·15 citations
2. 02*

   Nearly perturbative lattice-motivated QCD coupling with zero IR limit

   Cesar Ayala🇨🇱 · Gorazd Cvetic🇨🇱 · Reinhart Kogerler🇩🇪 · Igor Kondrashuk🇨🇱

   The product of the gluon dressing function and the square of the ghost dressing function in the Landau gauge can be regarded to represent, apart from the inverse power corrections 1/Q^{2n}, a nonperturbative generalization A(Q^2) of the perturbative QCD running coupling a(Q^2)=alpha_s(Q^2)/pi. Recent large volume lattice calculations for these dressing functions indicate that the coupling defined in such a way goes to zero as A(Q^2)~Q^2 when the squared momenta Q^2 go to zero (Q^2<<1 GeV^2). In this work we construct such a QCD coupling A(Q^2) which fulfills also various other physically motivated conditions. At high momenta it becomes the underlying perturbative coupling a(Q^2) to a very high precision. And at intermediate low squared momenta Q^2~1 GeV^2 it gives results consistent with the data of the semihadronic tau lepton decays as measured by OPAL and ALEPH. The coupling is constructed in a dispersive way, resulting as a byproduct in the holomorphic behavior of A(Q^2) in the complex Q^2-plane which reflects the holomorphic behavior of the spacelike QCD observables. Application of the Borel sum rules to tau-decay V+A spectral functions allows us to obtain values for the gluon (dimension-4) condensate and the dimension-6 condensate, which reproduce the measured OPAL and ALEPH data to a significantly better precision than the perturbative MSbar coupling approach.

   hep-phJ.Phys.G(2018)·52 citations
3. 03*

   Effective kinetic description of the expanding overoccupied Glasma

   Naoto Tanji🇩🇪 · Raju Venugopalan🇺🇸

   We report on a numerical study of the Boltzmann equation including $2\leftrightarrow 2$ scatterings of gluons and quarks in an overoccupied Glasma undergoing longitudinal expansion. We find that when a cascade of gluon number to the infrared occurs, corresponding to an infrared enhancement analogous to a transient Bose-Einstein condensate, gluon distributions qualitatively reproduce the results of classical-statistical simulations for the expanding Glasma. These include key features of the distributions that are not anticipated in the "bottom-up" thermalization scenario. We also find that quark distributions, like those of gluons, satisfy self-similar scaling distributions in the overoccupied Glasma. We discuss the implications of these results for a deeper understanding of the self-similarity and universality of parton distributions in the Glasma.

   hep-phnucl-thPRD(2017)·37 citations
4. 04*

   Possible signatures for tetraquarks from the decays of $a_0(980)$, $a_0(1450)$

   K. S. Kim🇰🇷 · Hungchong Kim🇰🇷

   Based on the recent proposal for the tetraquarks with the mixing scheme, we investigate fall-apart decays of $a_0(980),a_0(1450)$ into two lowest-lying mesons. This mixing scheme suggests that $a_0(980)$ and $a_0(1450)$ are the tetraquarks with the mixtures of two spin configurations of diquark and antidiquark. Due to the relative sign differences in the mixtures, the couplings of fall-apart decays into two mesons are strongly enhanced for $a_0(980)$ but suppressed for $a_0(1450)$. We report that this expectation is supported by their experimental decays. In particular, the ratios of the associated partial decay widths, which depend on some kinematical factors and the couplings, are found to be around $\Gamma [a_0(980)\to \pi \eta ]/\Gamma [a_0(1450)\to \pi \eta ]=2.51-2.54$, $\Gamma [a_0(980)\to K\bar{K}]/\Gamma [a_0(1450)\to K\bar{K}]=0.52-0.89$, which seems to agree with the experimental ratios reasonably well. This agreement can be interpreted as the tetraquark signatures for $a_0(980),a_0(1450)$.

   hep-phnucl-thEPJC(2017)·18 citations
5. 05*

   Studies of the hybrid star structure within 2+1 flavors NJL model

   Cheng-Ming Li🇨🇳 · Jin-Li Zhang🇨🇳 · Tong Zhao🇨🇳 · Ya-Peng Zhao🇨🇳 · Hong-Shi Zong🇨🇳

   In this paper we use the equation of state (EOS) of 2+1 flavors Nambu-Jona-Lasinio (NJL) model to study the structure of compact stars. To avoid the ultraviolet divergence, we employ the proper-time regularization (PTR) with an ultraviolet cutoff. For comparison, we fix three sets of parameters, where the constraints of chemical equilibrium and electric charge neutrality conditions are taken into consideration. With a certain interpolation method in the crossover region, we construct three corresponding hybrid EOSs but find that the maximum masses of hybrid stars in the three different cases don't differ too much. It should be pointed out that, the results we get are in accordance with the recent astro-observation PSR J0348+0432, PSR J1614-2230, PSR J1946+3417.

   hep-phPRD(2017)·28 citations
6. 06*

   Charmonium ground and excited states at finite temperature from complex Borel sum rules

   Ken-Ji Araki🇯🇵 · Kei Suzuki🇯🇵 · Philipp Gubler🇰🇷 · Makoto Oka🇯🇵

   Charmonium spectral functions in vector and pseudoscalar channels at finite temperature are investigated through the complex Borel sum rules and the maximum entropy method. Our approach enables us to extract the peaks corresponding to the excited charmonia, ${\psi }^{\prime }$ and ${\eta }_c^{\prime }$, as well as those of the ground states, $J/\psi$ and ${\eta }_c$, which has never been achieved in usual QCD sum rule analyses. We show the spectral functions in vacuum and their thermal modification around the critical temperature, which leads to the almost simultaneous melting (or peak disappearance) of the ground and excited states.

   hep-phhep-latnucl-exnucl-thPLB(2018)·6 citations
7. 07*

   Renormalization group: new relations between the parameters of the Standard Model

   S. Rebeca Juárez W.🇲🇽 · Piotr Kielanowski🇲🇽 · Gerardo Mora🇲🇽 · Arno Bohm🇺🇸

   We analyze the renormalization group equations for the Standard Model at the one and two loops levels. At one loop level we find an exact constant of evolution built from the product of the quark masses and the gauge couplings $g_1$ and $g_3$ of the $U(1)$ and $SU(3)$ groups. For leptons at one loop level we find that the ratio of the charged lepton mass and the power of $g_1$ varies $\simeq 4\times 10^{-5}$ in the whole energy range. At the two loop level we have found two relations between the quark masses and the gauge couplings that vary $\simeq 4\%$ and $\simeq 1\%$, respectively. For leptons at the two loop level we have derived a relation between the charged lepton mass and the gauge couplings $g_1$ and $g_2$ that varies $\simeq 0.1\%$. This analysis significantly simplifies the picture of the renormalization group evolution of the Standard Model and establishes new important relations between its parameters.

   hep-phPLB(2017)·3 citations
8. 08*

   Atomic Two-Body $(Z\alpha {)}^6$ Predictions

   John H. Connell🇺🇸

   For muonic hydrogen, positronium, and ordinary hydrogen, we show that the existence of a relativistic two-body wave equation whose energy levels are physically accurate to order $(Z\alpha {)}^4$ (where $Z\alpha$ is the binding coupling constant) implies a previously unknown two-body Sommerfeld energy formula which can be used to predict energy terms to order $(Z\alpha {)}^6$ using simple algebra. Two such terms are verified to be physically correct by earlier $(Z\alpha {)}^6$ calculations for positronium. For muonic hydrogen and ordinary hydrogen, these terms are predictions.

   hep-ph1 citation
9. 09*

   Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation

   N. Yamanaka🇯🇵 · B. K. Sahoo🇮🇳 · N. Yoshinaga🇯🇵 · T. Sato🇯🇵 · K. Asahi🇯🇵 · B. P. Das🇯🇵

   The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas -- particle, nuclear and atomic is reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested.

   hep-phnucl-thphysics.atom-phEPJA(2017)·201 citations
10. 10*

    Physics Behind Precision

    P. Azzi🇮🇹 · P. Azzurri🇮🇹 · S. Biswas🇰🇷 · F. Blekman🇧🇪 · G. Corcella🇮🇹 · S. De Curtis🇮🇹 · J. Erler🇲🇽 · N. Foppiani🇮🇹 · I. Helenius🇸🇪 · S. Jadach🇵🇱 · P. Janot🇨🇭 · F. Jegerlehner🇩🇪 and 10 other authors

    This document provides a writeup of contributions to the FCC-ee mini-workshop on "Physics behind precision" held at CERN, on 2-3 February 2016.

    hep-phhep-ex22 citations
11. 11*

    Predictions for the isolated prompt photon production at the LHC at $\sqrt{s}=$13 TeV

    Muhammad Goharipour🇮🇷 · Hossein Mehraban🇮🇷

    The prompt photon production in hadronic collisions has a long history of providing information on the substructure of hadrons and testing the perturbative techniques of QCD. Some valuable information about the parton densities in the nucleon and nuclei, especially of the gluon, can also be achieved by analysing the measurements of the prompt photon production cross section whether inclusively or in association with heavy quarks or jets. In this work, we present predictions for the inclusive isolated prompt photon production in $pp$ collisions at center-of-mass energy of 13 TeV using various modern PDF sets. The calculations are presented both as a function of photon transverse energy $E_{\text{T}}^{\gamma }$ and pseudorapidity ${\eta }^{\gamma }$ for the ATLAS kinematic coverage. We also study in detail the theoretical uncertainty in the cross sections due to the variation of the renormalization, factorization and fragmentation scales. Moreover, we introduce and calculate the ratios of photon momenta for different rapidity regions and study the impact of various input PDFs on such quantity.

    hep-phhep-exAdv.High Energy Phys.(2017)·9 citations
12. 12*

    New Resonances at LHC are possible. Multiple Point Principle and New Bound States in the Standard Model

    L.V. Laperashvili🇷🇺 · H.B. Nielsen🇩🇰 · C.D. Froggatt🇬🇧 · B.G. Sidharth🇮🇳 · C.R. Das🇷🇺

    In the present paper we argue that the correction to the Higgs mass coming from the bound state of 6 top and 6 anti-top quarks, predicted early by C.D. Froggatt, H.B. Nielsen and L.V. Laperashvili, leads to the Standard Model (SM) vacuum stability and confirms the accuracy of the multiple point principle (principle of degenerate vacua) for all experimentally valued SM parameters (Higgs mass, top-quark mass, etc.). The aim to get the vacua degeneracy requires a mass of the bound state in the region of 770 GeV.

    hep-ph2 citations
13. 13*

    Simulations of Cold Electroweak Baryogenesis: Finding the optimal quench time

    Zong-Gang Mou🇬🇧 · Paul M. Saffin🇬🇧 · Anders Tranberg🇳🇴

    We revisit the numerical computation of the baryon asymmetry from Cold Electroweak Baryogenesis given the physical Higgs mass. We investigate the dependence of the asymmetry on the speed at which electroweak symmetry breaking takes place. The maximum asymmetry does not occur for arbitrarily fast quenches, but at quench times of about ${\tau }_q\simeq 16m_H^{-1}$, with no asymmetry created for quenches slower than ${\tau }_q>30m_H^{-1}$. Curiously, we also find that the overall sign of the asymmetry depends on the quench time.

    hep-phhep-lathep-thJHEP(2017)·6 citations
14. 14*

    Signatures of Dirac and Majorana Sterile Neutrinos in Trilepton Events at the LHC

    Claudio O. Dib🇨🇱 · C. S. Kim🇰🇷 · Kechen Wang🇨🇳

    Heavy sterile neutrinos with masses below $M_W$ can induce trilepton events at the 14 TeV LHC through purely leptonic $W$ decays of $W^{\pm }\to e^{\pm }{e}^{\pm }{\mu }^{\mp }\nu$ and ${\mu }^{\pm }{\mu }^{\pm }{e}^{\mp }\nu$ where the heavy neutrino will be in an intermediate state on its mass shell. Discovery and exclusion limits for the heavy neutrinos are found using both Cut-and-Count (CC) and a Multi-Variate Analysis (MVA) methods in this study. We also show that it is possible to discriminate between a Dirac and a Majorana heavy neutrino, even when lepton number conservation cannot be directly tested due to unobservability of the final state neutrino. This discrimination is done by exploiting a combined set of kinematic observables that differ between the Majorana vs. Dirac cases. We find that the MVA method can greatly enhance the discovering and discrimination limits in comparison with the CC method. For a 14-TeV $pp$ collider with integrated luminosity of 3000 ${\mathrm{fb}}^{-1}$, sterile neutrinos can be found with 5$\sigma$ significance if heavy-to-light neutrino mixings $|U_{Ne}{|}^2\sim |U_{N\mu }{|}^2\sim 10^{-6}$, while the Majorana vs. Dirac type can be distinguished if $|U_{Ne}{|}^2\sim |U_{N\mu }{|}^2\sim 10^{-5}$ or even $|U_{N\ell }{|}^2\sim 10^{-6}$ if one of the mixing elements is at least an order of magnitude smaller than the other.

    hep-phhep-exPRD(2017)·34 citations
15. 15*

    Search for Heavy Sterile Neutrinos in Trileptons at the LHC

    Claudio O. Dib🇨🇱 · C. S. Kim🇰🇷 · Kechen Wang🇨🇳

    We present a search strategy for both Dirac and Majorana sterile neutrinos from the purely leptonic decays of $W^{\pm }\to e^{\pm }{e}^{\pm }{\mu }^{\mp }\nu$ and ${\mu }^{\pm }{\mu }^{\pm }{e}^{\mp }\nu$ at the 14 TeV LHC. The discovery and exclusion limits for sterile neutrinos are shown using both the Cut-and-Count (CC) and Multi-Variate Analysis (MVA) methods. We also discriminate between Dirac and Majorana sterile neutrinos by exploiting a set of kinematic observables which differ between the Dirac and Majorana cases. We find that the MVA method, compared to the more common CC method, can greatly enhance the discovery and discrimination limits. Two benchmark points with sterile neutrino mass $m_N=20$ GeV and 50 GeV are tested. For an integrated luminosity of 3000 ${\mathrm{fb}}^{-1}$, sterile neutrinos can be found with $5\sigma$ significance if heavy-to-light neutrino mixings $|U_{Ne}{|}^2\sim |U_{N\mu }{|}^2\sim 10^{-6}$, while Majorana vs. Dirac discrimination can be reached if at least one of the mixings is of order $10^{-5}$.

    hep-phhep-exCPC(2017)·23 citations
16. 16*

    Review of top charge asymmetries for LHC run II

    Susanne Westhoff🇩🇪

    This is a brief review of charge asymmetries in top-antitop quark production at the LHC. Proposed asymmetry observables in processes of associated top-pair production $t\bar{t}$ + jet, $t\bar{t}+W$, and $t\bar{t}+\gamma$ are analyzed and compared. While the focus is on standard-model predictions, we also comment on the sensitivity to possible new physics and observation prospects during the second runtime of the LHC.

    hep-phhep-exPoS(2017)·1 citation
17. 17*

    Predictions for Diffractive $\varphi$ Meson Production Using an AdS/QCD Light-front Wavefunction

    Mohammad Ahmady🇨🇦 · Ruben Sandapen🇨🇦 · Neetika Sharma🇮🇳

    We compute the rate for diffractive $\varphi$ electro-production using the Color Glass Condensate dipole model. The model parameters are obtained from fits to the most recent combined HERA data on inclusive deep inelastic scattering. As for the $\varphi$ meson, we use an AdS/QCD holographic light front wavefunction. Our predictions are compared to the available data collected at the HERA collider.

    hep-phAIP Conf.Proc.(2017)·0 citations
18. 18*

    Transverse Single Spin Asymmetry in $p+p^{\uparrow }\to J/\psi +X$

    Rohini M. Godbole🇮🇳 · Abhiram Kaushik🇮🇳 · Anuradha Misra🇮🇳 · Vaibhav Rawoot🇮🇳 · Bipin Sonawane🇮🇳

    We present estimates of transverse single spin asymmetry (TSSA) in $p+p^{\uparrow }\to J/\psi +X$ within the colour evaporation model of charmonium production in a generalized parton model (GPM) framework, using the recently obtained best fit parameters for the gluon Sivers function (GSF) extracted from PHENIX data on TSSA in $p+p^{\uparrow }\to {\pi }^0+X$ at midrapidity. We calculate asymmetry at $\sqrt{s}=200$ GeV, and compare the results with PHENIX data on TSSA in the process $p+p^{\uparrow }\to J/\psi +X$. We also present estimates for asymmetry at $\sqrt{s}=115$ GeV corresponding to the proposed fixed target experiment AFTER@LHC and at $\sqrt{s}=500$ GeV corresponding to the higher RHIC energy. Finally, we investigate the effect of the transverse momentum dependent (TMD) evolution of the densities involved, on the asymmetry.

    hep-phPRD(2017)·23 citations
19. 19*

    Non-standard Higgs couplings in single Higgs boson production at the LHC and future linear collider

    G. Akkaya Selcin🇹🇷 · I. Sahin🇹🇷

    We investigate the potential of single Higgs boson production at the LHC and at egamma mode of future linear electron-positron collider to probe non-standard HZgamma and Hgammagamma couplings. We consider the semi-elastic production process pp-> p gamma p-> pHqX at the LHC where q represents the quarks and X represents the remnants of one of the initial protons. We also study the single Higgs production through gamma e-> He in the egamma collision at the future linear collider. We perform a model-independent analysis and obtain the sensitivity bounds on the non-standard Higgs couplings for both colliders.

    hep-phChin.J.Phys.(2017)·8 citations
20. 20*

    Spin-dependent $\mu \to e$ conversion

    Vincenzo Cirigliano🇺🇸 · Sacha Davidson🇫🇷 · Yoshitaka Kuno🇯🇵

    The experimental sensitivity to $\mu \to e$ conversion on nuclei is expected to improve by four orders of magnitude in coming years. We consider the impact of $\mu \to e$ flavour-changing tensor and axial-vector four-fermion operators which couple to the spin of nucleons. Such operators, which have not previously been considered, contribute to $\mu \to e$ conversion in three ways: in nuclei with spin they mediate a spin-dependent transition; in all nuclei they contribute to the coherent ($A^2$-enhanced) spin-independent conversion via finite recoil effects and via loop mixing with dipole, scalar, and vector operators. We estimate the spin-dependent rate in Aluminium (the target of the upcoming COMET and Mu2e experiments), show that the loop effects give the greatest sensitivity to tensor and axial-vector operators involving first-generation quarks, and discuss the complementarity of the spin-dependent and independent contributions to $\mu \to e$ conversion

    hep-phPLB(2017)·86 citations
21. 21*

    A new relativistic viscous hydrodynamics code and its application to the Kelvin-Helmholtz instability in high-energy heavy-ion collisions

    Kazuhisa Okamoto🇯🇵 · Chiho Nonaka🇯🇵

    We construct a new relativistic viscous hydrodynamics code optimized in the Milne coordinates. We split the conservation equations into an ideal part and a viscous part, using the Strang spitting method. In the code a Riemann solver based on the two-shock approximation is utilized for the ideal part and the Piecewise Exact Solution (PES) method is applied for the viscous part. We check the validity of our numerical calculations by comparing analytical solutions, the viscous Bjorken's flow and the Israel-Stewart theory in Gubser flow regime. Using the code, we discuss possible development of the Kelvin-Helmholtz instability in high-energy heavy-ion collisions.

    ↳ nucl-thhep-exhep-phEPJC(2017)·21 citations
22. 22*

    Poincaré gauge gravity: an emergent scenario

    J.L. Chkareuli🇬🇪

    The Poincaré gauge gravity (PGG) with the underlying vector fields of tetrads and spin-connections is perhaps the best theory candidate for gravitation to be unified with the other three elementary forces of nature. There is a clear analogy between local frame in PGG and local internal symmetry space in the Standard Model. As a result, the spin-connection fields, gauging the local frame Lorentz symmetry group SO(1,3)_{LF}, appear in PGG much as photons and gluons appear in SM. We propose that such an analogy may follow from their common emergent nature allowing to derive PGG in the same way as conventional gauge theories. In essence, we start with an arbitrary theory of some vector and fermion fields which possesses only global spacetime symmetries, such as Lorentz and translational invariance, in flat Minkowski space. The two vector field multiplets involved are proposed to belong, respectively, to the adjoint (A_{{\mu}}^{ij}) and vector (e_{{\mu}}^{i}) representations of the starting global Lorentz symmetry. We show that if these prototype vector fields are covariantly constrained, A_{{\mu}}^{ij}A_{ij}^{{\mu}}=M_{A} and e_{{\mu}}^{i}e_{i}^{{\mu}}=M_{e}, thus causing a spontaneous violation of the accompanying global symmetries (M_{A,e} are their proposed violation scales), then the only possible theory compatible with these length-preserving constraints is turned out to be the gauge invariant PGG, while the corresponding massless (pseudo)Goldstone modes are naturally collected in the emergent gauge fields of tetrads and spin-connections. In a minimal theory case being linear in a curvature we unavoidably come to the Einstein-Cartan theory. The extending theories with propagating spin-connection and tetrad modes are also considered and their possible unification with the Standard Model is briefly discussed.

    ↳ gr-qchep-phhep-thPRD(2017)·1 citation
23. 23*

    Cosmological Dynamics of D-BIonic and DBI Scalar Field and Coincidence Problem of Dark Energy

    Sirachak Panpanich🇯🇵 · Kei-ichi Maeda🇯🇵 · Shuntaro Mizuno🇯🇵

    We study the cosmological dynamics of D-BIonic and DBI scalar field, which is coupled to matter fluid. For the exponential potential and the exponential couplings, we find a new analytic scaling solution yielding the accelerated expansion of the Universe. Since it is shown to be an attractor for some range of the coupling parameters, the density parameter of matter fluid can be the observed value, as in the coupled quintessence with a canonical scalar field. Contrary to the usual coupled quintessence, where the value of matter couple giving observed density parameter is too large to satisfy observational constraint from CMB, we show that the D-BIonic theory can give similar solution with much smaller value of matter coupling. As a result, together with the fact that the D-BIonic theory has a screening mechanism, the D-BIonic theory can solve the so-called coincidence problem as well as the dark energy problem.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2017)·7 citations
24. 24*

    COSMOS-$e^{\prime }$- soft Higgsotic attractors

    Sayantan Choudhury🇮🇳

    In this work, we have developed an elegant algorithm to study the cosmological consequences from a huge class of quantum field theories (i.e. superstring theory, supergravity, extra dimensional theory, modified gravity etc.), which are equivalently described by soft attractors in the effective field theory framework. In this description we have restricted our analysis for two scalar fields - dilaton and Higgsotic fields minimally coupled with Einstein gravity, which can be generalized for any arbitrary number of scalar field contents with generalized non-canonical and non-minimal interactions. We have explicitly used $R^2$ gravity, from which we have studied the attractor and non-attractor phase by exactly computing two point, three point and four point correlation functions from scalar fluctuations using In-In (Schwinger-Keldysh) and $\delta \mathcal{N}$ formalism. We have also presented theoretical bounds on the amplitude, tilt and running of the primordial power spectrum, various shapes (equilateral, squeezed, folded kite or counter collinear) of the amplitude as obtained from three and four point scalar functions, which are consistent with observed data. Also the results from two point tensor fluctuations and field excursion formula are explicitly presented for attractor and non-attractor phase. Further, reheating constraints, scale dependent behaviour of the couplings and the dynamical solution for the dilaton and Higgsotic fields are also presented. New sets of consistency relations between two, three and four point observables are also presented, which shows significant deviation from canonical slow roll models. Additionally, three possible theoretical proposals have presented to overcome the tachyonic instability at the time of late time acceleration. Finally, we have also provided the bulk interpretation from the three and four point scalar correlation functions for completeness.

    ↳ hep-thastro-ph.COgr-qchep-phEPJC(2017)·36 citations
25. 25*

    Electroexcitation of nucleon resonances of the [70,1-] multiplet in a light-front relativistic quark model

    Inna Aznauryan🇺🇸 · Volker Burkert🇺🇸

    We utilize a light-front relativistic quark model to predict the 3q core contribution to the electroexcitation of nucleon resonances of the [70,1-] multiplet on the proton and neutron at Q2 < 5GeV2. The investigation is stimulated in large degree by expected progress in the studies of the electroexcitation of nucleon resonances in the third resonance region in the CLAS experiment. For the resonances N(1520)3/2-, N(1535)1/2-, and N(1675)5/2-, experimental data on electroexcitation amplitudes on the proton are available in a wide range of Q2. This allowed us to quantify the expected meson-baryon contributions to these amplitudes as a function of Q2.

    ↳ nucl-thhep-phPRC(2017)·27 citations
26. 26*

    Inclusive semi-leptonic B meson decay structure functions from lattice QCD

    Shoji Hashimoto🇯🇵

    We propose a method to non-perturbatively calculate the forward-scattering matrix elements relevant to inclusive semi-leptonic B meson decays. Corresponding hadronic structure functions at unphysical kinematics are accessible through lattice QCD calculation of four-point correlation functions. The unphysical kinematical point may be reached by analytic continuation from the physical differential decay rate. A numerical test is performed for the B_s -> X_c l nu mode in the zero-recoil limit. We use lattice ensembles generated with 2+1 dynamical quark flavors. The valence charm quark mass is tuned to its physical value, while the bottom quark mass is varied in the range (1.56-2.44)m_c. From the numerical results we can identify the contributions of the ground state D_s^(*) meson as well as those of excited states or continuum states.

    ↳ hep-lathep-exhep-phPTEP(2017)·73 citations
27. 27*

    Topological Properties of the Chiral Magnetic Effect in Multi-Weyl Semimetals

    Tomoya Hayata🇯🇵 · Yuta Kikuchi🇯🇵 · Yuya Tanizaki🇺🇸

    We compute the chiral magnetic effect (CME) in multi-Weyl semimetals (multi-WSMs) based on the chiral kinetic theory. Multi-WSMs are WSMs with multiple monopole charges that have nonlinear and anisotropic dispersion relations near Weyl points, and we need to extend conventional computation of CME in WSMs with linear dispersion relations. Topological properties of CME in multi-WSMs are investigated in details for not only static magnetic fields but also time-dependent (dynamic) ones. We propose an experimental setup to measure the multiple monopole charge via the topological nature hidden in the dynamic CME.

    ↳ cond-mat.mes-hallhep-phPRB(2017)·13 citations
28. 28*

    Transverse Momentum Spectra and Nuclear Modification Factor using Boltzmann Transport Equation with Flow in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV

    Sushanta Tripathy🇮🇳 · Arvind Khuntia🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Raghunath Sahoo🇮🇳

    In the continuation of our previous work, the transverse momentum ($p_T$) spectra and nuclear modification factor ($R_{AA}$) are derived using relaxation time approximation of Boltzmann Transport Equation (BTE). The initial $p_T$-distribution used to describe $p+p$ collisions has been studied with the pQCD inspired power-law distribution, the Hagedorn's empirical formula and with the Tsallis non-extensive statistical distribution. The non-extensive Tsallis distribution is observed to describe the complete range of the transverse momentum spectra. The Boltzmann-Gibbs Blast Wave (BGBW) distribution is used as the equilibrium distribution in the present formalism, to describe the $p_T$-distribution and nuclear modification factor in nucleus-nucleus collisions. The experimental data for Pb+Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV at the Large Hadron Collider at CERN have been analyzed for pions, kaons, protons, $K^{\ast 0}$ and $\varphi$. It is observed that the present formalism while explaining the transverse momentum spectra upto 5 GeV/c, explains the nuclear modification factor very well upto 8 GeV/c in $p_T$ for all these particles except for protons. $R_{AA}$ is found to be independent of the degree of non-extensivity, $q_{pp}$ after $p_T\sim$ 8 GeV/c.

    ↳ nucl-thhep-phnucl-exEPJA(2017)·22 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.