Thu·Mar 15, 2018Thursday·March 15, 2018

1. 01*

   Continuity of vortices from the hadronic to the color-flavor locked phase in dense matter

   Mark G. Alford🇺🇸 · Gordon Baym🇺🇸 · Kenji Fukushima🇯🇵 · Tetsuo Hatsuda🇯🇵 · Motoi Tachibana🇯🇵

   We study how vortices in dense superfluid hadronic matter can connect to vortices in superfluid quark matter, as in rotating neutron stars, focusing on the extent to which quark-hadron continuity can be maintained. As we show, a singly quantized vortex in three-flavor symmetric hadronic matter can connect smoothly to a singly quantized non-Abelian vortex in three-flavor symmetric quark matter in the color-flavor locked (CFL) phase, without the necessity for boojums appearing at the transition.

   hep-phnucl-thPRD(2019)·51 citations
2. 02*

   Limiting fragmentation in high-energy nuclear collisions at the CERN Large Hadron Collider

   Pragati Sahoo🇮🇳 · Pooja Pareek🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Raghunath Sahoo🇮🇳

   The hypothesis of limiting fragmentation (LF) or it is called otherwise recently, as extended longitudinal scaling, is an interesting phenomena in high energy multiparticle production process. This paper discusses about different regions of phase space and their importance in hadron production, giving special emphasis on the fragmentation region. Although it was conjectured as a universal phenomenon in high energy physics, with the advent of higher center-of-mass energies, it has become prudent to analyse and understand the validity of such hypothesis in view of the increasing inelastic nucleon-nucleon cross-section (${\sigma }_{\mathrm{in}}$). In this work, we revisit the phenomenon of limiting fragmentation for nucleus-nucleus (A+A) collisions in the pseudorapidity distribution of charged particles at various energies. We use energy dependent ${\sigma }_{\mathrm{in}}$ to transform the charged particle pseudorapidity distributions ($d{N}_{ch}^{\mathrm{AA}}/d\eta$) into differential cross-section per unit pseudorapidity ($d{\sigma }^{\mathrm{AA}}/d\eta$) of charged particles and study the phenomenon of LF. We find that in $d{\sigma }^{\mathrm{AA}}/d\eta$ LF seems to be violated at LHC energies while considering the energy dependent ${\sigma }_{\mathrm{in}}$. We also perform a similar study using A Multi-Phase Transport (AMPT) Model with string melting scenario and also find that LF is violated at LHC energies.

   hep-phhep-exnucl-exnucl-thPRC(2019)·11 citations
3. 03*

   Study of $B^{-}\to \Lambda \bar{p}{\eta }^{{(}^{\prime })}$ and ${\bar{B}}_s^0\to \Lambda \bar{\Lambda }{\eta }^{{(}^{\prime })}$ decays

   Y.K. Hsiao🇨🇳 · C.Q. Geng🇨🇳 · Yao Yu🇨🇳 · H.J. Zhao🇨🇳

   We study the three-body baryonic $B\to \mathbf{B}{\bar{\mathbf{B}}}^{\prime }M$ decays with $M$ representing the $\eta$ or ${\eta }^{\prime }$ meson. Particularly, we predict that $\mathcal{B}(B^{-}\to \Lambda \bar{p}\eta ,\Lambda \bar{p}{\eta }^{\prime })=(5.3\pm 1.4,3.3\pm 0.7)\times 10^{-6}$ or $(4.0\pm 0.7,4.6\pm 1.1)\times 10^{-6}$, where the errors arise from the non-factorizable effects as well as the uncertainties in the $0\to \mathbf{B}{\bar{\mathbf{B}}}^{\prime }$ and $B\to \mathbf{B}{\bar{\mathbf{B}}}^{\prime }$ transition form factors, while the two different results are due to overall relative signs between the form factors, causing the constructive and destructive interference effects. For the corresponding baryonic ${\bar{B}}_s^0$ decays, we find that $\mathcal{B}({\bar{B}}_s^0\to \Lambda \bar{\Lambda }\eta ,\Lambda \bar{\Lambda }{\eta }^{\prime })=(1.2\pm 0.3,2.6\pm 0.8)\times 10^{-6}$ or $(2.1\pm 0.6,1.5\pm 0.4)\times 10^{-6}$ with the errors similar to those above. The decays in question are accessible to the experiments at BELLE and LHCb.

   hep-phhep-exEPJC(2019)·6 citations
4. 04*

   Direct numerical computation and its application to the higher-order radiative corrections

   K Kato🇯🇵 · E de Doncker🇺🇸 · T Ishikawa🇯🇵 · F Yuasa🇯🇵

   The direct computation method(DCM) is developed to calculate the multi-loop amplitude for general masses and external momenta. The ultraviolet divergence is under control in dimensional regularization. In this paper we report on the progress of DCM to several scalar multi-loop integrals after the presentation in ACAT2016. Also the discussion is given on the application of DCM to physical 2-loop processes including numerator functions.

   hep-phJ.Phys.Conf.Ser.(2018)·1 citation
5. 05*

   Impacts of multi-Higgs on the $\rho$ parameter, decays of a neutral Higgs to $WW$ and $ZZ$, and a charged Higgs to $WZ$

   Jian-Yong Cen🇨🇳 · Jung-Hsin Chen🇹🇼 · Xiao-Gang He🇹🇼 · Jhih-Ying Su🇹🇼

   In the standard model (SM), the $\rho$ parameter is equal to 1 and the ratio ${\lambda }_{WZ}$ of Higgs $\to ZZ$ and Higgs $\to WW$ is also equal to 1 at the tree level. When going beyond the SM with more than one types of Higgs representations these quantities may be different from the SM predictions which can provide crucial information about new physics. There may also exist a certain charged Higgs $h^{+}$ decays into a $W^{+}$ and a $Z$. Imposing a custodial symmetry can force the parameter $\rho$ to be equal to 1 with certain predictions for ${\lambda }_{WZ}$ and $h^{+}\to W^{+}Z$. However, imposing $\rho =1$ without custodial symmetry may have different predictions. We show how differences arise and how to use experimental data to obtain information about the underlying physics in a model with the SM plus a real and a complex $SU(2{)}_L$ triplets.

   hep-phhep-exInt.J.Mod.Phys.A(2018)·6 citations
6. 06*

   $P_c$-like pentaquarks in hidden strange sector

   Hongxia Huang · Jialun Ping

   Analogous to the work of hidden charm molecular pentaquarks, we study possible hidden strange molecular pentaquarks composed of $\Sigma$ (or ${\Sigma }^{\ast }$) and $K$ (or $K^{\ast }$) in the framework of quark delocalization color screening model. Our results suggest that the $\Sigma K$, $\Sigma K^{\ast }$ and ${\Sigma }^{\ast }{K}^{\ast }$ with $I{J}^P=\frac{1}{2}{\frac{1}{2}}^{-}$ and $\Sigma K^{\ast }$, ${\Sigma }^{\ast }K$ and ${\Sigma }^{\ast }{K}^{\ast }$ with $I{J}^P=\frac{1}{2}{\frac{3}{2}}^{-}$ are all resonance states by coupling the open channels. The molecular pentaquark ${\Sigma }^{\ast }K$ with quantum numbers $I{J}^P=\frac{1}{2}{\frac{3}{2}}^{-}$ can be seen as a strange partner of the LHCb $P_c(4380)$ state, and it can be identified as the nucleon resonance $N^{\ast }(1875)$ listed in PDG. The $\Sigma K^{\ast }$ with quantum numbers $I{J}^P=\frac{1}{2}{\frac{3}{2}}^{-}$ can be identified as the $N^{\ast }(2100)$, which was experimentally observed in the $\varphi$ photo-production.

   hep-phnucl-thPRD(2018)·28 citations
7. 07*

   Dispersion relation formalism for the two-photon exchange correction to elastic muon-proton scattering: elastic intermediate state

   Oleksandr Tomalak🇩🇪 · Marc Vanderhaeghen🇩🇪

   We evaluate the two-photon exchange correction to the unpolarized cross section in the elastic muon-proton scattering within dispersion relations. One of the six independent invariant amplitudes requires a subtraction. We fix the subtraction function to the model estimate of the full two-photon exchange at one of three MUSE beam energies and make a prediction for the two other energies. Additionally, we present single and double polarization observables accounting for the lepton mass.

   hep-phnucl-exnucl-thEPJC(2018)·39 citations
8. 08*

   Thermodynamic limit in high-multiplicity $pp$ collisions at $\sqrt{s}$ = 7 TeV

   Natasha Sharma🇮🇳 · Jean Cleymans🇿🇦 · Boris Hippolyte🇫🇷

   An analysis is made of the particle composition in the final state of $pp$ collisions at 7 TeV as a function of the charged particle multiplicity ($d{N}_{ch}/d\eta$). The thermal model is used to determine the chemical freeze-out temperature as well as the radius and strangeness suppression factor ${\gamma }_s$. Three different ensembles are used in the analysis. The grand canonical ensemble, the canonical ensemble with exact strangeness conservation and the canonical ensemble with exact baryon number, strangeness and electric charge conservation. It is shown that for the highest multiplicity class the three ensembles lead to the same result. This allows us to conclude that this multiplicity class is close to the thermodynamic limit. It is estimated that the final state in $pp$ collisions could reach the thermodynamic limit when $d{N}_{ch}/d\eta$ is larger than twenty per unit of rapidity, corresponding to about 300 particles in the final state when integrated over the full rapidity interval.

   hep-phnucl-thAdv.High Energy Phys.(2019)·17 citations
9. 09*

   Effective field theory for the nucleon-quarkonium interaction

   Jaume Tarrús Castellà🇪🇸 · Gastão Krein🇧🇷

   We develop an effective field theory approach for the $S$-wave quarkonium-nucleon system. We adopt a natural power counting equivalent to Weinberg's power counting in nucleon-nucleon effective field theories and compute the quarkonium-nucleon potential, scattering length and effective range up to $\mathcal{O}(m_{\pi }^3/{\Lambda }_{\chi }^3)$ accuracy, including the full light-quark mass dependence. We compare our results with lattice QCD studies of quarkonium-nucleon system, obtain an estimation of the leading order quarkonium-nucleon contact term and determine the $J/\psi$ and ${\eta }_c$ chromopolarizabilities.

   hep-phnucl-thPRD(2018)·52 citations
10. 10*

    Exotic Gravitational Wave Signatures from Simultaneous Phase Transitions

    Djuna Croon🇨🇦 · Graham White🇨🇦

    We demonstrate that the relic gravitational wave background from a multi-step phase transition may deviate from the simple sum of the single spectra, for phase transitions with similar nucleation temperatures $T_N$. We demonstrate that the temperature range $\Delta T$ between the volume fractions $f(T)=0.1$ and $f(T)=0.9$ occupied by the vacuum bubbles can span $\sim 20$ GeV. This allows for a situation in which phase transitions overlap, such that the later bubbles may nucleate both in high temperature and intermediate temperature phases. Such scenarios may lead to more exotic gravitational wave spectra, which cannot be fitted that of a consecutive PTs. We demonstrate this explicitly in the singlet extension of the Standard Model. Finally, we comment on potential additional effects due to the more exotic dynamics of overlapping phase transitions.

    hep-phastro-ph.COJHEP(2018)·38 citations
11. 11*

    A Higgsploding Theory of Dark Matter

    Valentin V. Khoze🇬🇧 · Joey Reiness🇬🇧 · Jakub Scholtz🇬🇧 · Michael Spannowsky🇬🇧

    We show that the Higgsplosion mechanism makes a prediction for the mass and coupling of a WIMP-like minimal scalar dark matter model. In particular the currently favoured minimal value for the Higgsplosion scale, $E_{\mathrm{H}}\sim 25$ TeV, implies a dark matter mass $m_{\mathrm{DM}}\sim 1.25$ TeV and a moderate quartic coupling with the Standard Model Higgs field ${\lambda }_{\mathrm{H},\mathrm{DM}}\sim 0.4$. This point in the parameter space is still allowed by all current experimental bounds, including direct detection (XENON), indirect detection (HESS, Fermi, Planck) and collider searches. We have updated the scalar dark matter bounds to reflect the latest results from XENON and HESS experiments. We also comment on vacuum stability and dark matter self-interactions in this model.

    hep-phastro-ph.CO11 citations
12. 12*

    Measuring properties of a Heavy Higgs boson in the $H\to t\bar{t}\to b{W}^{+}\bar{b}{W}^{-}$ decay

    Jung Chang🇰🇷 · Kingman Cheung🇹🇼 · Jae Sik Lee🇰🇷 · Chih-Ting Lu🇹🇼 · Jubin Park🇰🇷

    Suppose a heavy neutral Higgs or scalar boson $H$ is discovered at the LHC, it is important to investigate its couplings to the standard model particles as much as possible. Here in this work we attempt to probe the CP-even and CP-odd couplings of the heavy Higgs boson to a pair of top quarks, through the decay $H\to t\bar{t}\to b{W}^{+}\bar{b}{W}^{-}$. We use the helicity-amplitude method to write down the most general form for the angular distributions of the final-state $b$ quarks and $W$ bosons. We figure out that there are 6 types of angular observables and, under CP$\tilde{\mathrm{T}}$ conservation, one-dimensional angular distributions can only reveal two of them. Nevertheless, the $H$ couplings to the $t\bar{t}$ pair can be fully determined by exploiting the one-dimensional angular distributions. A Higgs-boson mass of 380 GeV not too far above the $t\bar{t}$ threshold is illustrated with full details. With a total of $10^4$ events of $H\to t\bar{t}\to b{W}^{+}\bar{b}{W}^{+}$, one can determine the couplings up to 10-20 % uncertainties.

    hep-phJHEP(2018)·1 citation
13. 13*

    Time reversal invariance violation for high energy charged baryons in bent crystals

    V.G. Baryshevsky🇧🇾

    Spin precession of channelled particles in bent crystals at the LHC gives unique possibility for measurements as electric and magnetic moments of charm, beauty and strange charged baryons so and constants determining CP ($T_{odd},P_{odd}$) violation interactions and $P_{odd},T_{even}$ interactions of baryons with electrons and nucleus (nucleons). For a particle moving in a bent crystal a new effect caused by nonelastic processes arises: in addition to the spin precession around the direction of the effective magnetic field (bend axis), the direction of electric field and the direction of the particle momentum, the spin rotation to the mentioned directions also appears.

    hep-ph13 citations
14. 14*

    Neutron-proton mass difference from gauge/gravity duality

    Francesco Bigazzi🇮🇹 · Pierluigi Niro🇮🇹

    Using gauge/gravity duality as a tool, we compute the strong sector, isospin breaking induced contribution to the neutron-proton mass difference in the Witten-Sakai-Sugimoto model of large $N$ QCD with two non-degenerate light flavors. The mass difference, for which we provide an analytic expression, turns out to be positive and proportional to the down-up quark mass splitting, consistently with expectations and previous estimates based on effective QCD models. Extrapolating the model parameters to fit QCD hadronic observables, we find that the strong sector contribution to the nucleon mass splitting overcomes the electromagnetic contribution and is about $0.25\%$ of the average nucleon mass in the model, a result which approaches recent lattice QCD estimates. Our formula is extended to resonances and $\Delta$ baryons. We thus use it to compute the strong sector contribution to $\Delta$ baryons mass differences. Finally, we also provide details of how isospin breaking affects the holographic instanton solution describing the baryons.

    ↳ hep-thhep-lathep-phPRD(2018)·16 citations
15. 15*

    The propagating speed of relic gravitational waves and their refractive index during inflation

    Massimo Giovannini🇨🇭

    If the refractive index of the tensor modes increases during a conventional inflationary stage of expansion the relic graviton spectrum is tilted towards high frequencies. Two apparently diverse parametrizations of this effect are shown to be related by a rescaling of the four-dimensional metric through a conformal factor that involves the refractive index itself. Non-monotonic spectra with a maximum in the MHz region correspond to a limited variation of the refractive index terminating well before the end of inflation. After exploring a general approach encompassing the ones proposed so far, we estimate the required sensitivity for the direct detection of the predicted gravitational radiation and demonstrate that the allowed regions of the parameter space are within reach for some of the planned detectors operating either in the audio band (like Ligo/Virgo and Kagra) or in the mHz band (like Lisa, Bbo and Decigo).

    ↳ gr-qcastro-ph.COhep-phhep-thEPJC(2018)·17 citations
16. 16*

    Evidence for a New Component of High-Energy Solar Gamma-Ray Production

    Tim Linden🇺🇸 · Bei Zhou🇺🇸 · John F. Beacom🇺🇸 · Annika H. G. Peter🇺🇸 · Kenny C. Y. Ng🇮🇱 · Qing-Wen Tang🇺🇸

    The observed multi-GeV gamma-ray emission from the solar disk --- sourced by hadronic cosmic rays interacting with gas, and affected by complex magnetic fields --- is not understood. Utilizing an improved analysis of the Fermi-LAT data that includes the first resolved imaging of the disk, we find strong evidence that this emission is produced by two separate mechanisms. Between 2010-2017 (the rise to and fall from solar maximum), the gamma-ray emission is dominated by a polar component. Between 2008-2009 (solar minimum) this component remains present, but the total emission is instead dominated by a new equatorial component with a brighter flux and harder spectrum. Most strikingly, although 6 gamma rays above 100 GeV are observed during the 1.4 years of solar minimum, none are observed during the next 7.8 years. These features, along with a 30-50 GeV spectral dip which will be discussed in a companion paper, were not anticipated by theory. To understand the underlying physics, Fermi and HAWC observations of the imminent Cycle 25 solar minimum are crucial.

    ↳ astro-ph.HEastro-ph.SRhep-phPRL(2018)·66 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.