Wed·Nov 9, 2016Wednesday·November 9, 2016

1. 01*

   Applications of KP Nuclear Parton Distributions

   Sergey Kulagin🇷🇺 · Roberto Petti🇺🇸

   We review the nuclear parton distribution functions computed on the basis of our microscopic model taking into account a number of nuclear effects including Fermi motion and nuclear binding, nuclear meson-exchange currents, off-shell corrections to bound nucleon distributions and nuclear shadowing. We discuss applications to a number of different processes including lepton-nucleus deep inelastic scattering, proton-nucleus Drell-Yan lepton pair production at Fermilab, as well as $W^{\pm }$ and $Z^0$ boson production in proton-lead collisions at the LHC.

   hep-phhep-exnucl-exnucl-thPoS(2016)·0 citations
2. 02*

   A map of the non-thermal WIMP

   Hyungjin Kim🇰🇷 · Jeong-Pyong Hong🇯🇵 · Chang Sub Shin🇰🇷

   We study the effect of the elastic scattering on the non-thermal WIMP, which is produced by direct decay of heavy particles at the end of reheating. The non-thermal WIMP becomes important when the reheating temperature is well below the freeze-out temperature. Usually, two limiting cases have been considered. One is that the produced high energetic dark matter particles are quickly thermalized due to the elastic scattering with background radiations. The corresponding relic abundance is determined by the thermally averaged annihilation cross-section at the reheating temperature. The other one is that the initial abundance is too small for the dark matter to annihilate so that the final relic is determined by the initial amount itself. We study the regions between these two limits, and show that the relic density depends not only on the annihilation rate, but also on the elastic scattering rate. Especially, the relic abundance of the p-wave annihilating dark matter crucially relies on the elastic scattering rate because the annihilation cross-section is sensitive to the dark matter velocity. We categorize the parameter space into several regions where each region has distinctive mechanism for determining the relic abundance of the dark matter at the present Universe. The consequence on the (in)direct detection is also studied.

   hep-phastro-ph.COPLB(2017)·12 citations
3. 03*

   Asymmetric Dark Matter and Baryogenesis from Pseudoscalar Inflation

   Yann Cado🇨🇭 · Eray Sabancilar🇨🇭

   We show that both the baryon asymmetry of the Universe and the dark matter abundance can be explained within a single framework that makes use of maximally helical hypermagnetic fields produced during pseudoscalar inflation and the chiral anomaly in the Standard Model. We consider a minimal asymmetric dark matter model free from anomalies and constraints. We find that the observed baryon and the dark matter abundances are achieved for a wide range of inflationary parameters, and the dark matter mass ranges between 7-15 GeV. The novelty of our mechanism stems from the fact that the same source of CP violation occurring during inflation explains both baryonic and dark matter in the Universe with two inflationary parameters, hence addressing all the initial condition problems in an economical way.

   hep-phastro-ph.COhep-thJCAP(2017)·24 citations
4. 04*

   Mass Predictions of Open-Flavour Hybrid Mesons from QCD Sum Rules

   Jason Ho🇨🇦 · Derek Harnett🇨🇦 · Tom Steele🇨🇦

   Within QCD, colourless states may be constructed corresponding to exotic matter outside of the traditional quark model. Experiments have recently observed tetraquark and pentaquark states, but no definitive hybrid meson signals have been observed. With the construction of the PANDA experiment at FAIR, and with full commissioning of the GlueX experiment at JLab expected to be completed this year, the opportunity for the observation of hybrid mesons has greatly increased. However, theoretical calculations are necessary to ascertain the identity of any experimental resonances that may be observed. We present selected QCD sum rule results from a full range of quantum numbers for open-flavour hybrid mesons with heavy valence quark content, including non-perturbative condensate contributions up to six-dimensions.

   hep-phPoS(2016)·0 citations
5. 05*

   Enhanced Higgs associated production with a top quark pair in the NMSSM with light singlets

   Marcin Badziak🇵🇱 · Carlos E. M. Wagner🇺🇸

   Precision measurements of the 125 GeV Higgs resonance recently discovered at the LHC have determined that its properties are similar to the ones of the Standard Model (SM) Higgs boson. However, the current uncertainties in the determination of the Higgs boson couplings leave room for significant deviations from the SM expectations. In fact, if one assumes no correlation between the top-quark and gluon couplings to the Higgs, the current global fit to the Higgs data lead to central values of the Higgs couplings to the bottom-quark and the top-quark that are about 2 $\sigma$ away from the SM predictions. In a previous work, we showed that such a scenario could be realized in the Next to Minimal Supersymmetric extension of the SM (NMSSM), for heavy singlets and light MSSM-like Higgs bosons and scalar top quarks, but for couplings that ruined the perturbative consistency of the theory up to the GUT scale. In this work we show that a perturbative consistent scenario, for somewhat heavier stops, may be obtained in the presence of light singlets. An interesting bonus of this scenario is the possibility of explaining an excess of events observed in CP-even Higgs searches at LEP2.

   hep-phhep-exJHEP(2017)·20 citations
6. 06*

   Prediction of anomalous ${\rm Y}(5S)\to {\rm Y}(1^3{D}_J)\eta$ transitions

   Bo Wang🇨🇳 · Dian-Yong Chen🇨🇳 · Xiang Liu🇨🇳

   In this work, we study the hadronic loop contribution to the ${\rm Y}(5S)\to {\rm Y}(1^3{D}_J)\eta$ ($J=1,2,3$) transitions. We predict that the branching ratios of ${\rm Y}(5S)\to {\rm Y}(1^3{D}_1)\eta$, ${\rm Y}(5S)\to {\rm Y}(1^3{D}_2)\eta$ and ${\rm Y}(5S)\to {\rm Y}(1^3{D}_3)\eta$ can reach up to $(0.5\sim 5.1)\times 10^{-3}$, $(0.7\sim 7.5)\times 10^{-3}$ and $(0.9\sim 9.6)\times 10^{-4}$, respectively. Since these predicted hadronic transitions of ${\rm Y}(5S)$ are comparable with these observed ${\rm Y}(5S)\to {\rm Y}(nS){\pi }^{+}{\pi }^{-}$ $(n=1,2,3)$, we suggest future experiment like Belle and BelleII to carry out the search for these anomalous ${\rm Y}(5S)\to {\rm Y}(1^3{D}_J)\eta$ transitions.

   hep-phhep-exPRD(2016)·27 citations
7. 07*

   EW baryogenesis via DM

   Marek Lewicki🇵🇱

   We discuss the impact of a swifter cosmological expansion induced by modified cosmological history of the universe on scenarios realising electroweak baryogenesis. We detail the possible experimental bounds one can place on such cosmological modification and show how the detection capabilities of particle models are modified within these bounds. On the particle physics side we focus on the Standard Model supplemented by a dimension six operator which directly modifies the Higgs potential. We show that due to the cosmological modification, electroweak baryogenesis in this model can be realized, with the modification of the triple Higgs coupling below HL-LHC sensitivity.

   hep-ph2 citations
8. 08*

   Spin polarization and color superconductivity in the Nambu--Jona-Lasinio model at finite temperature

   Hiroaki Matsuoka (Kochi Univ., Japan)🇯🇵 · Yasuhiko Tsue (Kochi Univ., Japan)🇯🇵 · Joao da Providencia (Univ. de Coimbra, Portugal)🇵🇹 · Constancia Providencia (Univ. de Coimbra, Portugal)🇵🇹 · Masatoshi Yamamura (Kansai Univ., Japan)🇯🇵

   We investigate the possible existence of spin polarization and color superconductivity in the Nambu--Jona-Lasinio model with a tensor-type interaction at finite density and temperature. The thermodynamic potential is calculated by the functional integral method. Numerical results indicate that at low temperature and quark chemical potential the chiral condensed phase exists, and at intermediate chemical potential the color superconducting phase appears. In addition, depending on the magnitude of the tensor coupling, at large chemical potential and low temperature, a color superconducting phase and a spin polarized phase may coexist while at intermediate temperatures only the spin polarized phase occurs.

   hep-phnucl-thPRD(2017)·11 citations
9. 09*

   The elliptic gluon GTMD inside a large nucleus

   Jian Zhou🇨🇳

   We evaluate the elliptic gluon Generalized Transverse Momentum Dependent(GTMD) distribution inside a large nucleus using the McLerran-Venugopalan model. We further show that this gluon distribution can be probed through the angular correlation in virtual photon quasi-elastic scattering on a nucleus.

   hep-phPRD(2016)·76 citations
10. 10*

    Remarkable signals of $t_R$ compositeness

    G.J. Gounaris🇬🇷 · F.M. Renard🇫🇷

    We are looking for remarkable differences between predictions of the standard model and those of $t_R$ compositeness (while the $t_L$ remains elementary) in various basic $t\bar{t}$ production processes, without having to make difficult final polarization analyses. We assume the presence of $q^2$ dependent form factors which first suppress the $t_R$ contributions at high $q^2$, and in addition, may also lead to an effective $q^2$ dependent top mass. We further assume that these effects disappear at low $q^2$ so that there are no anomalous couplings. We show that large specific differences indeed appear in the high energy limits of cross sections and asymmetries in $e^{-}{e}^{+}$, gluon+gluon, $\gamma \gamma$ collisions and other fusion processes and that this should lead to a strategy for analyzing them.

    hep-ph19 citations
11. 11*

    Saturation and geometrical scaling

    Michal Praszalowicz🇵🇱

    We discuss emergence of geometrical scaling as a consequence of the nonlinear evolution equations of QCD, which generate a new dynamical scale, known as the saturation momentum: Qs. In the kinematical region where no other energy scales exist, particle spectra exhibit geometrical scaling (GS), i.e. they depend on the ratio pT=Qs, and the energy dependence enters solely through the energy dependence of the saturation momentum. We confront the hypothesis of GS in different systems with experimental data.

    hep-phEPJ Web Conf.(2017)·0 citations
12. 12*

    Color reconnection and event-by-event fluctuations of mean transverse momentum in proton-proton collisions at sqrt_s = 7 TeV in PYTHIA6.4

    Qingjun Liu🇨🇳 · Wei-Qin Zhao🇨🇳

    Based on PYTHIA6.428, event-by-event fluctuations of the mean transverse momentum in proton- proton collisions at sqrt_s = 7 TeV are studied using several measures of the fluctuations. The study compares results of the fluctuations for events where color reconnection is turned on, with those where color reconnection is turned off. The comparison reveals that some of the fluctuation measures are much more sensitive to color reconnection than others. Through the comparison it is demonstrated for the first time that for proton-proton collisions at the Large Hadron Collider, these sensitive measures of the mean transverse momentum fluctuations can serve as alternative probes to color reconnection and color reconnection is a non-trivial source of the event-by-event fluctuations.

    hep-phhep-ex5 citations
13. 13*

    Confinement, Holonomy and Correlated Instanton-Dyon Ensemble I: SU(2) Yang-Mills Theory

    Miguel Angel Lopez-Ruiz🇺🇸 · Yin Jiang🇺🇸 · Jinfeng Liao🇺🇸

    The mechanism of confinement in Yang-Mills theories remains a challenge to our understanding of nonperturbative gauge dynamics. While it is widely perceived that confinement may arise from chromo-magnetically charged gauge configurations with nontrivial topology, it is not clear what types of configurations could do that and how, in pure Yang-Mills and QCD-like (non-supersymmetric) theories. Recently a promising approach has emerged, based on statistical ensembles of dyons/anti-dyons that are constituents of instanton/anti-instanton solutions with nontrivial holonomy where the holonomy plays a vital role as an effective "Higgsing" mechanism. We report a thorough numerical investigation of the confinement dynamics in SU(2) Yang-Mills theory by constructing such a statistical ensemble of correlated instanton-dyons.

    hep-phnucl-thPRD(2018)·15 citations
14. 14*

    Calculation of gluon contribution to the proton spin by using the non-perturbative quantization à la Heisenberg

    Vladimir Dzhunushaliev🇰🇿

    The contribution of crossed gluon fields in flux tubes connecting quarks to the proton spin is calculated. The calculations are performed following non-perturbative Heisenberg's quantization technique. In our approach a proton is considered as consisting of three quarks connected by three flux tubes. The flux tubes contain color longitudinal electric and transversal electric and magnetic fields. The transversal fields causes the appearance of the angular momentum density. The dimensionless relation between the angular momentum and the mass of the gluon fields is obtained. The contribution to proton spin from rotating quarks and flux tubes connecting quarks is estimated. Simple numerical relation between the proton mass, the speed of light and the proton radius, which is of the same order as the Planck constant, is discussed.

    hep-phhep-thPhys.Part.Nucl.Lett.(2017)·0 citations
15. 15*

    Topological susceptibility in finite temperature (2+1)-flavor QCD using gradient flow

    Yusuke Taniguchi🇯🇵 · Kazuyuki Kanaya🇯🇵 · Hiroshi Suzuki🇯🇵 · Takashi Umeda🇯🇵

    We compute the topological charge and its susceptibility in finite temperature (2+1)-flavor QCD on the lattice applying a gradient flow method. With the Iwasaki gauge action and nonperturbatively $O(a)$-improved Wilson quarks, we perform simulations on a fine lattice with~$a\simeq 0.07\mathrm{fm}$ at a heavy $u$, $d$ quark mass with $m_{\pi }/m_{\rho }\simeq 0.63$ but approximately physical $s$ quark mass with $m_{{\eta }_{ss}}/m_{\varphi }\simeq 0.74$. In a temperature range from~$T\simeq 174\mathrm{MeV}$ ($N_t=16$) to $697\mathrm{MeV}$ ($N_t=4$), we study two topics on the topological susceptibility. One is a comparison of gluonic and fermionic definitions of the topological susceptibility. Because the two definitions are related by chiral Ward-Takahashi identities, their equivalence is not trivial for lattice quarks which violate the chiral symmetry explicitly at finite lattice spacings. The gradient flow method enables us to compute them without being bothered by the chiral violation. We find a good agreement between the two definitions with Wilson quarks. The other is a comparison with a prediction of the dilute instanton gas approximation, which is relevant in a study of axions as a candidate of the dark matter in the evolution of the Universe. We find that the topological susceptibility shows a decrease in $T$ which is consistent with the predicted ${\chi }_{\mathrm{t}}(T)\propto (T/T_{\mathrm{pc}}{)}^{-8}$ for three-flavor QCD even at low temperature $T_{\mathrm{pc}}<T\le 1.5T_{\mathrm{pc}}$.

    ↳ hep-lathep-phhep-thPRD(2017)·79 citations
16. 16*

    Radial acceleration relation and dissipative dark matter

    Olga Chashchina🇫🇷 · Robert Foot🇦🇺 · Zurab Silagadze🇷🇺

    Observations indicate that ordinary matter, the baryons, influence the structural properties of dark matter on galactic scales. One such indication is the radial acceleration relation, which is a tight correlation between the measured gravitational acceleration and that expected from the baryons. We show here that the dark matter density profile that has been motivated by dissipative dark matter models, including mirror dark matter, can reproduce this radial acceleration relation.

    ↳ astro-ph.GAhep-phPRD(2017)·19 citations
17. 17*

    Field-strength correlators for QCD in a magnetic background

    Enrico Meggiolaro🇮🇹 · Massimo D'Elia🇮🇹 · Michele Mesiti🇮🇹 · Francesco Negro🇮🇹

    We present the results of an exploratory study (by means of Monte Carlo simulations on the lattice) of the properties of the gauge-invariant two-point correlation functions of the gauge-field strengths for $N_f=2$ QCD at zero temperature and in the presence of a magnetic background field: the analysis provides evidence for the emergence of anisotropies in the nonperturbative part of the correlators and for an increase of the gluon condensate as a function of the external magnetic field.

    ↳ hep-lathep-phhep-thPoS(2016)·0 citations
18. 18*

    Prediction of positive parity $B_s$ mesons and search for the $X(5568)$

    Daniel Mohler🇩🇪 · C.B. Lang🇦🇹 · Sasa Prelovsek🇸🇮

    We use a combination of quark-antiquark and $B^{(\ast )}K$ interpolating fields to predict the mass of two QCD bound states below the $B^{\ast }K$ threshold in the quantum channels $J^P=0^{+}$ and $1^{+}$. The mesons correspond to the b-quark cousins of the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ and have not yet been observed in experiment, even though they are expected to be found by LHCb. In addition to these predictions, we obtain excellent agreement of the remaining p-wave energy levels with the known $B_{s1}(5830)$ and $B_{s2}^{\ast }(5840)$ mesons. The results from our first principles calculation are compared to previous model-based estimates. More recently the D0 collaboration claimed the existence of an exotic resonance $X(5568)$ with exotic flavor content $\bar{b}s\bar{d}u$. If such a state with $J^P=0^{+}$ exists, only the decay into $B_s\pi$ is open which makes a lattice search for this state much cleaner and simpler than for other exotic candidates involving heavy quarks. We conclude, however, that we do not find such a candidate in agreement with a recent LHCb result.

    ↳ hep-lathep-phPoS(2016)·0 citations
19. 19*

    The falsification of Chiral Nuclear Forces

    E. Ruiz Arriola🇪🇸 · J. E. Amaro🇪🇸 · R. Navarro Perez🇺🇸

    Predictive power in theoretical nuclear physics has been a major concern in the study of nuclear structure and reactions. The Effective Field Theory (EFT) based on chiral expansions provides a model independent hierarchy for many body forces at long distances but their predictive power may be undermined by the regularization scheme de- pendence induced by the counterterms and encoding the short distances dynamics which seem to dominate the uncertainties. We analyze several examples including zero energy NN scattering or perturbative counterterm-free peripheral scattering where one would ex- pect these methods to work best and unveil relevant systematic discrepancies when a fair comparison to the Granada-2013 NN-database and partial wave analysis is undertaken.

    ↳ nucl-thhep-phEPJ Web Conf.(2017)·8 citations
20. 20*

    Production of charmed baryons in $\bar{p}p$ collisions close to their thresholds

    J. Haidenbauer🇩🇪 · G. Krein🇧🇷

    Cross sections for the charm-production reactions $\bar{p}p\to {\bar{\Lambda }}_c^{-}{\Sigma }_c^{+}$, ${\bar{\Sigma }}_c{\Sigma }_c$, ${\bar{\Xi }}_c{\Xi }_c$, and ${\bar{\Xi }}_c^{\prime }{\Xi }_c^{\prime }$ are presented, for energies near their respective thresholds. The results are based on a calculation performed in the meson-exchange framework in close analogy to earlier studies of the Jülich group on the strangeness-production reactions $\bar{p}p\to \bar{\Lambda }\Sigma$, $\bar{\Sigma }\Sigma$, $\bar{\Xi }\Xi$ by connecting the two sectors via SU(4) flavor symmetry. The cross sections are found to be in the order of $0.1-1$ $\mu b$ at energies of $100$ MeV above the respective thresholds, for all considered channels. Complementary to meson-exchange, where the charmed baryons are produced by the exchange of $D$ and $D^{\ast }$ mesons, a charm-production potential derived in a quark model is employed for assessing uncertainties. The cross sections predicted within that picture turned out to be significantly smaller.

    ↳ nucl-thhep-phPRD(2017)·15 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.