Mon·Apr 17, 2017Monday·April 17, 2017

1. 01*

   Cut Moments approach in the analysis of DIS data

   D. Kotlorz🇵🇱 · S. V. Mikhailov🇷🇺 · O. V. Teryaev🇷🇺 · A. Kotlorz🇵🇱

   We review the main results on the generalization of the DGLAP evolution equations within the cut Mellin moments (CMM) approach, which allows one to overcome the problem of kinematic constraints in Bjorken $x$. CMM obtained by multiple integrations as well as multiple differentiations of the original parton distribution also satisfy the DGLAP equations with the simply transformed evolution kernel. The CMM approach provides novel tools to test QCD; here we present one of them. Using appropriate classes of CMM, we construct the generalized Bjorken sum rule that allows us to determine the Bjorken sum rule value from the experimental data in a restricted kinematic range of $x$. We apply our analysis to COMPASS data on the spin structure function $g_1$.

   hep-phPRD(2017)·9 citations
2. 02*

   Scrutinizing the Higgs quartic coupling at a future 100 TeV proton-proton collider with taus and b-jets

   Benjamin Fuks🇫🇷 · Jeong Han Kim🇺🇸 · Seung J. Lee🇰🇷

   The Higgs potential consists of an unexplored territory in which the electroweak symmetry breaking is triggered, and it is moreover directly related to the nature of the electroweak phase transition. Measuring the Higgs boson cubic and quartic couplings, or getting equivalently information on the exact shape of the Higgs potential, is therefore an essential task. However, direct measurements beyond the cubic self-interaction of the Higgs boson consist of a huge challenge, even for a future proton-proton collider expected to operate at a center-of-mass energy of 100 TeV. We present a novel approach to extract model-independent constraints on the triple and quartic Higgs self-coupling by investigating triple Higgs-boson hadroproduction at a center-of-mass energy of 100 TeV, focusing on the $\tau \tau b\bar{b}b\bar{b}$ channel that was previously overlooked due to a supposedly too large background. It is thrown into sharp relief that the assist from transverse variables such as $m_{T2}$ and a boosted configuration ensures a high signal sensitivity. We derive the luminosities that would be required to constrain given deviations from the Standard Model in the Higgs self-interactions, showing for instance that a $2\sigma$ sensitivity could be achieved for an integrated luminosity of 30 ab${}^{-1}$ when Standard Model properties are assumed. With the prospects of combining these findings with other triple-Higgs search channels, the Standard Model Higgs quartic coupling could in principle be reached with a significance beyond the $3\sigma$ level.

   hep-phPLB(2017)·59 citations
3. 03*

   ExDiff Monte Carlo generator for Exclusive Diffraction. Version 1.0. Physics and manual

   R.A. Ryutin🇷🇺 · V.A. Petrov🇷🇺

   ExDiff is a Monte Carlo event generator for simulation of Exclusive Diffractive processes in proton-proton collisions. The present version includes reactions: elastic scattering $pp\to pp$ at 7, 8, 13, 14~TeV; $pp\to p+R+p$, $R=f_0(1710),f_2(1950)$ at 13~TeV. In the future versions many processes of Central Exclusive Diffractive Production will be added.

   hep-ph2 citations
4. 04*

   $L_{\mu }-L_{\tau }$ gauge-boson production from lepton flavor violating $\tau$ decays at Belle II

   Chuan-Hung Chen🇹🇼 · Takaaki Nomura🇰🇷

   $L_{\mu }-L_{\tau }$ gauge boson ($Z^{\prime }$) with a mass in the MeV to GeV region can resolve not only the muon $g-2$ excess, but also the gap in the high-energy cosmic neutrino spectrum at IceCube. It was recently proposed that such a light gauge boson can be detected during the Belle II experiment with a luminosity of 50 ab${}^{-1}$ by the $e^{+}{e}^{-}\to \gamma +\text{slashed}E$ process through the kinetic mixing with the photon, where the missing energy $\text{slashed}E$ is from the $Z^{\prime }\to \bar{\nu }\nu$ decays. We study the phenomenological implications when a pair of singlet vector-like leptons carrying different $L_{\mu }-L_{\tau }$ charges are included, and a complex singlet scalar (${\varphi }_S$) is introduced to accomplish the spontaneous $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry breaking. It is found that the extension leads to several phenomena of interest, including (i) branching ratio (BR) for $h\to \mu \tau$ can be of the order of $10^{-3}$; (ii) ${\varphi }_S$-mediated muon $g-2$ can be of the order of $10\times 10^{-10}$; (iii) BR for $\tau \to \mu {\varphi }_S^{\ast }\to \mu Z^{\prime }{Z}^{\prime }$ can be $10^{-8}$, and (iv) kinetic mixing between the $Z^{\prime }$ boson and photon is sensitive to the relative heavy lepton masses. The predicted BRs for $\tau \to (3\mu +\text{slashed}E,5\mu$) through the leptonic $Z^{\prime }$ decays can reach a level of $10^{-9}$, in which the results fall within the sensitivity of the Belle II in the search for the rare tau decays.

   hep-phhep-exPRD(2017)·29 citations
5. 05*

   Effective Sextic Superpotential and $B-L$ violation in NMSGUT

   Charanjit S. Aulakh🇮🇳 · Ram Lal Awasthi🇮🇳 · S. Krishna (IISER Mohali)🇮🇳

   We list operators of the superpotential of the effective MSSM that emerges from the NMSGUT up to sextic degree. We give illustrative expressions for the coefficients in terms of NMSGUT parameters. We also estimate the impact of GUT scale threshold corrections on these effective operators in view of the demonstration that $B$ violation via quartic superpotential terms can be suppressed to acceptable levels after including such corrections in the NMSGUT. We find a novel $B,B-L$ violating quintic operator that leads to the decay mode $n\to e^{-}{K}^{+}$. We also remark that the threshold corrections to the Type I seesaw mechanism make the deviation of right handed neutrino masses from the GUT scale more natural while Type II seesaw neutrino masses, which earlier tended to utterly negligible receive threshold enhancement. Our results are of relevance for analyzing $B-L$ violating operator based, sphaleron safe, Baryogenesis.

   hep-phPramana(2017)·1 citation
6. 06*

   Understanding $X(3862)$, $X(3872)$, and $X(3930)$ in a Friedrichs-model-like scheme

   Zhi-Yong Zhou🇨🇳 · Zhiguang Xiao🇨🇳

   We developed a Friedrichs-model-like scheme in studying the hadron resonance phenomenology and present that the hadron resonances might be regarded as the Gamow states produced by a Hamiltonian in which the bare discrete state is described by the result of usual quark potential model and the interaction part is described by the quark pair creation model. In a one-parameter calculation, the $X(3862)$, $X(3872)$, and $X(3930)$ state could be simultaneously produced with a quite good accuracy by coupling the three P-wave states, ${\chi }_{c2}(2P)$, ${\chi }_{c1}(2P)$, ${\chi }_{c0}(2P)$ predicted in the Godfrey-Isgur model to the $D\bar{D}$, $D{\bar{D}}^{\ast }$, $D^{\ast }{\bar{D}}^{\ast }$ continuum states. At the same time, we predict that the $h_c(2P)$ state is at about 3902 MeV with a pole width of about 54 MeV. In this calculation, the $X(3872)$ state has a large compositeness. This scheme may shed more light on the long-standing problem about the general discrepancy between the prediction of the quark model and the observed values, and it may also provide reference for future search for the hadron resonance state.

   hep-phhep-exnucl-thPRD(2017)·46 citations
7. 07*

   An Effective Model of QCD Monopoles

   Adith Ramamurti🇺🇸 · Edward Shuryak🇺🇸

   In this work, we carried out quantum many-body studies of magnetic monopole ensembles through numerical simulations of the path integral for one- and two-component Coulomb Bose systems. We found the relation between the critical temperature for the Bose-Einstein condensation phase transition and the Coulomb coupling strength using two methods, the finite-size scaling of the superfluid fraction and statistical analysis of permutation cycles. After finding parameters that match the correlation functions measured in our system with the correlation functions previously measured on the lattice, we arrived at an effective quantum model of color magnetic monopoles in QCD. From this matched model, we were able to extract the monopole contribution to QCD equation of state near $T_{\text{c}}$.

   hep-phhep-latnucl-thNPA(2017)·0 citations
8. 08*

   Effective Field Theory Models for Thermal QCD

   Sourendu Gupta🇮🇳 · Rishi Sharma🇮🇳

   We present an effective field theory model for QCD at finite temperature with quarks. We discuss the mean field theory, the fixing of parameters, and a prediction for the curvature of the critical line. We proceed to write down a pionic theory of fluctuations around the mean field, and discuss how the parameters of this pionic effective theory descend from the model with quarks.

   hep-phhep-lathep-thnucl-thNPA(2017)·1 citation
9. 09*

   Maximal Cuts in Arbitrary Dimension

   Jorrit Bosma🇨🇭 · Mads Sogaard🇺🇸 · Yang Zhang🇨🇭

   We develop a systematic procedure for computing maximal unitarity cuts of multiloop Feynman integrals in arbitrary dimension. Our approach is based on the Baikov representation in which the structure of the cuts is particularly simple. We examine several planar and nonplanar integral topologies and demonstrate that the maximal cut inherits IBPs and dimension shift identities satisfied by the uncut integral. Furthermore, for the examples we calculated, we find that the maximal cut functions from different allowed regions, form the Wronskian matrix of the differential equations on the maximal cut.

   ↳ hep-thhep-phJHEP(2017)·105 citations
10. 10*

    A study of top-quark mass measurement using the lepton energy distribution at the Large Hadron Collider

    Seo Hyun An🇰🇷 · Sayaka Kawabata🇰🇷 · Tae Jeong Kim🇰🇷

    We present a feasibility study of top-quark mass measurement using the energy distribution of a lepton from a W boson in a top quark decay in pp collisions at the LHC. The proposed method requires only the lepton energy distribution at the parton level. The analysis is performed in the lepton + jets final state by using fast simulation data corresponding to an integrated luminosity of approximately 20 fb-1 at 14 TeV. Events with exactly one lepton, at least 3 jets and at least 1 b jet are selected. The lepton energy distribution at the parton level is obtained by applying the bin-by-bin unfolding technique. The study shows that the pole mass of the top quark can be measured within an uncertainty of 1 GeV.

    ↳ hep-exhep-phEPJC(2017)·2 citations
11. 11*

    Phenomenological QCD equations of state for neutron star mergers

    Toru Kojo🇨🇳

    Thermal QCD equations of state at high baryon density are sensitive to the phase structure and the resulting excitation modes. The leading contribution at low temperature can be either ~p_F^2 T^2 (pF: Fermi momentum, T: temperature) for phases with gapless quarks, or ~T^4 for phases with gapped quarks. In the latter the thermal pressure is dominated by collective modes. Starting with a schematic quark model developed for neutron star structure, we estimate the thermal contributions and zero point energy from the Nambu-Goldstone modes by building them upon the mean field background for the color-flavor-locked quark matter. Applying the phase shift representation for thermodynamic potentials, we include not only the bound state pairs but also resonating pairs. According to the Levinson's theorem, the high energy contributions tend to cancel the pole contributions to the thermodynamics, tempering the UV behaviors in the zero point energy. Our primary target in this talk is the domain with baryon density nB as large as ~ 5-10n_0 (n_0 = 0.16 fm^{-3}: nuclear saturation density), and the temperature T of the order ~30-100 MeV. The insights into this domain may be obtained through the future detection of gravitational waves from neutron star merging events.

    ↳ nucl-thastro-ph.HEhep-phNPA(2017)·2 citations
12. 12*

    Characterization of the initial state and QGP medium from a combined Bayesian analysis of LHC data at 2.76 and 5.02 TeV

    Jonah E. Bernhard🇺🇸 · J. Scott Moreland🇺🇸 · Steffen A. Bass🇺🇸

    We perform a global Bayesian analysis of a modern event-by-event heavy-ion collision model and LHC data at $\sqrt{s}$ = 2.76 and 5.02 TeV. After calibration, the model simultaneously describes multiplicity, transverse momentum, and flow data at both beam energies. We report new constraints on the scaling of initial-state entropy deposition and QGP transport coefficients, including a quantitative estimate of the temperature-dependent shear viscosity $(\eta /s)(T)$.

    ↳ nucl-thhep-phnucl-exNPA(2017)·21 citations
13. 13*

    Electromagnetic fields from quantum sources in heavy-ion collisions

    Balthazar Peroutka🇺🇸 · Kirill Tuchin🇺🇸

    We compute the electromagnetic field created by an ultrarelativistic charged particle in vacuum at distances comparable to the particle Compton wavelength. The wave function of the particle is governed by the Klein-Gordon equation, for a scalar particle, or the Dirac equation, for a spin-half particle. The produced electromagnetic field is essentially different in magnitude and direction from the Coulomb field, induced by a classical point charge, due to the quantum diffusion effect. Thus, a realistic computation of the electromagnetic field produced in heavy-ion collisions must be based upon the full quantum treatment of the valence quarks.

    ↳ nucl-thhep-phNPA(2017)·4 citations
14. 14*

    Empirical Determination of Dark Matter Velocities using Metal-Poor Stars

    Jonah Herzog-Arbeitman🇺🇸 · Mariangela Lisanti🇺🇸 · Piero Madau🇺🇸 · Lina Necib🇺🇸

    The Milky Way dark matter halo is formed from the accretion of smaller subhalos. These sub-units also harbor stars---typically old and metal-poor---that are deposited in the Galactic inner regions by disruption events. In this Letter, we show that the dark matter and metal-poor stars in the Solar neighborhood share similar kinematics due to their common origin. Using the high-resolution Eris simulation, which traces the evolution of both the dark matter and baryons in a realistic Milky-Way analog galaxy, we demonstrate that metal-poor stars are indeed effective tracers for the local, virialized dark matter velocity distribution. The local dark matter velocities can therefore be inferred from observations of the stellar halo made by the Sloan Digital Sky Survey within 4 kpc of the Sun. This empirical distribution differs from the Standard Halo Model in important ways and suggests that the bounds on the spin-independent scattering cross section may be weakened for dark matter masses below $\sim$10 GeV. Data from Gaia will allow us to further refine the expected distribution for the smooth dark matter component, and to test for the presence of local substructure.

    ↳ astro-ph.GAastro-ph.COhep-phPRL(2018)·73 citations
15. 15*

    Phenomenology of the muon-induced neutron yield

    Alexey Malgin🇷🇺

    The cosmogenic neutron yield $Y_n$ characterizes the matter ability to produce neutrons under the effect of cosmic ray muons with spectrum and average energy corresponding to an observation depth. The yield is the basic characteristic of cosmogenic neutrons. The neutron production rate and neutron flux both are derivatives of the yield. The constancy of the exponents $\alpha$ and $\beta$ in the known dependences of the yield on energy $Y_n\propto E_{\mu }^{\alpha }$ and the atomic weight $Y_n\propto A^{\beta }$ allows to combine these dependences in a single formula and to connect the yield with muon energy loss in the matter. As a result, the phenomenological formulas for the yield of muon-induced charged pions and neutrons can be obtained. These expressions both are associated with nuclear loss of the ultrarelativistic muons, which provides the main contribution to the total neutron yield. The total yield can be described by a universal formula, which is the best fit of experimental data.

    ↳ nucl-thhep-phPRC(2017)·14 citations
16. 16*

    Quantifying the Chiral Magnetic Effect from Anomalous-Viscous Fluid Dynamics

    Shuzhe Shi🇺🇸 · Yin Jiang🇩🇪 · Elias Lilleskov🇺🇸 · Yi Yin🇺🇸 · Jinfeng Liao🇺🇸

    In this contribution we report a recently developed Anomalous-Viscous Fluid Dynamics (AVFD) framework, which simulates the evolution of fermion currents in QGP on top of the bulk expansion from data-validated VISHNU hydrodynamics. With reasonable estimates of initial conditions and magnetic field lifetime, the predicted CME signal is quantitatively consistent with change separation measurements in 200GeV Au-Au collisions at RHIC. We further develop the event-by-event AVFD simulations that allow direct evaluation of two-particle correlations arising from CME signal as well as the non-CME backgrounds. Finally we report predictions from AVFD simulations for the upcoming isobaric (Ru-Ru v.s. Zr-Zr ) collisions that could provide the critical test of the CME in heavy ion collisions.

    ↳ nucl-thhep-phNPA(2017)·3 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.