Mon·Jun 17, 2019Monday·June 17, 2019

1. 01*

   Forward elastic scattering: Dynamical gluon mass and semihard interactions

   M. Broilo🇧🇷 · D. A. Fagundes🇧🇷 · E.G.S. Luna🇧🇷 · M.J. Menon🇧🇷

   The role of low-$x$ parton dynamics in dictating the high-energy behavior of forward scattering observables at LHC energies is investigated using a QCD-based model with even-under-crossing amplitude dominance at high-energies. We explore the effects of different sets of pre- and post-LHC fine-tuned parton distributions on the forward quantities ${\sigma }_{tot}$ and $\rho$, from $pp$ and $\bar{p}p$ scattering in the interval 10 GeV - 13 TeV. We also investigate the role of the leading soft contribution, the low-energy cuttoff, and the energy dependence of the semihard form factor on these observables. We show that in all cases investigated the highly restrictive data on $\rho$ parameter at $\sqrt{s}=13$ TeV indicate that a crossing-odd component may play a crucial role in forward elastic scattering at the highest energies. In the Regge language an odd-under-crossing object is called Odderon.

   hep-phhep-exEPJC(2019)·10 citations
2. 02*

   Inclusive production of two rapidity-separated heavy quarks as a probe of BFKL dynamics

   Andrèe Dafne Bolognino🇮🇹 · Francesco Giovanni Celiberto🇮🇹 · Michael Fucilla🇮🇹 · Dmitry Yu. Ivanov🇷🇺 · Beatrice Murdaca🇮🇹 · Alessandro Papa🇮🇹

   The inclusive photoproduction of two heavy quarks, separated by a large rapidity interval, is proposed as a new channel for the manifestation of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. The extension to the hadroproduction case is also discussed.

   hep-phPoS(2019)·60 citations
3. 03*

   Efficient Fourier Transforms for Transverse Momentum Dependent Distributions

   Zhong-Bo Kang🇺🇸 · Alexei Prokudin🇺🇸 · Nobuo Sato🇺🇸 · John Terry🇺🇸

   Hadron production at low transverse momenta in semi-inclusive deep inelastic scattering can be described by transverse momentum dependent (TMD) factorization. This formalism has also been widely used to study the Drell-Yan process and back-to-back hadron pair production in $e^{+}{e}^{-}$ collisions. These processes are the main ones for extractions of TMD parton distribution functions and TMD fragmentation functions, which encode important information about nucleon structure and hadronization. One of the most widely used TMD factorization formalism in phenomenology formulates TMD observables in coordinate $b_{\perp }$-space, the conjugate space of the transverse momentum. The Fourier transform from $b_{\perp }$-space back into transverse momentum space is sufficiently complicated due to oscillatory integrands that it requires a careful and computationally intensive numerical treatment in order to avoid potentially large numerical errors. Within the TMD formalism, the azimuthal angular dependence is analytically integrated and the two-dimensional $b_{\perp }$ integration reduces to a one-dimensional integration over the magnitude $b_{\perp }$. In this paper we develop a fast numerical Hankel transform algorithm for such a $b_{\perp }$-integration that improves the numerical accuracy of TMD calculations in all standard processes. Libraries for this algorithm are implemented in Python 2.7 and 3, C++, as well as FORTRAN77. All packages are made available open source.

   hep-phhep-exComput.Phys.Commun.(2021)·17 citations
4. 04*

   Probing inequivalent forms of Legget-Garg inequality in subatomic systems

   Javid Naikoo🇮🇳 · Swati Kumari🇮🇳 · Subhashish Banerjee🇮🇳 · A. K. Pan🇮🇳

   We study various formulations of Leggett-Garg inequality (LGI), specifically, the Wigner and Clauser-Horne forms of LGI, in the context of subatomic systems, in particular, three flavor neutrino as well as meson systems. The optimal forms of various LGIs for either neutrinos or mesons are seen to depend on measurement settings. For the neutrinos, some of these inequalities can be written completely in terms of experimentally measurable probabilities. Hence, the Wigner and Clauser-Horne forms of LGI are found to be more suitable as compared to the standard LGI from the experimental point of view for the neutrino system. Further, these inequalities exhibit maximum quantum violation around the energies roughly corresponding to the maximum neutrino flux. The Leggett-Garg type inequality is seen to be more suited for the meson dynamics. The meson system being inherently a decaying system, allows one to see the effect of decoherence on the extent of violation of various inequalities. Decoherence is observed to reduce the degree of violation, and hence the nonclassical nature of the system.

   hep-phquant-phJ.Phys.G(2020)·16 citations
5. 05*

   X(3872) in a hot pion bath

   Martin Cleven🇪🇸 · Volodymyr K. Magas🇪🇸 · Angels Ramos🇪🇸

   Right since its discovery in 2003 by the Belle collaboration, establishing the nature of the $X(3872)$ meson has been one of the main priorities in the field of quarkonium physics. Not qualifying as a conventional $c\bar{c}$ state, the multiquark structure of this exotic meson has received very different interpretations, ranging from a compact tetraquark configuration to an extended $D{\bar{D}}^{\ast }+c.c.$ molecule. In this work we explore the effect that a hot pion bath may have in the properties of the $X(3872)$, assuming this state to be a $D{\bar{D}}^{\ast }+c.c.$ molecule. We derive the finite temperature effects on the $X(3872)$ from a coupled channels unitarized amplitude, obtained including the properties of the charmed mesons under such conditions. We find that the $X(3872)$ develops a subtantial width, of the order of a few tens of MeV, in hot pionic environments at temperatures $100-150$ MeV, and its nominal mass moves above the $D{D}^{\ast }$ threshold. The fact that the $X(3872)$ in a hot pion gas may no longer be a narrow resonance needs to be considered in the estimation of production yields in relativistic heavy-ion collisions.

   hep-phPLB(2019)·18 citations
6. 06*

   Loop Tree Duality for multi-loop numerical integration

   Zeno Capatti🇨🇭 · Valentin Hirschi🇨🇭 · Dario Kermanschah🇨🇭 · Ben Ruijl🇨🇭

   Loop Tree Duality (LTD) offers a promising avenue to numerically integrate multi-loop integrals directly in momentum space. It is well-established at one loop, but there have been only sparse numerical results at two loops. We provide a formal derivation for a novel multi-loop LTD expression and study its threshold singularity structure. We apply our findings numerically to a diverse set of up to four-loop finite topologies with kinematics for which no contour deformation is needed. We also lay down the ground work for constructing such a deformation. Our results serve as an important stepping stone towards a generalised and efficient numerical implementation of LTD, applicable to the computation of virtual corrections.

   hep-phPRL(2019)·120 citations
7. 07*

   Neutrino flavor oscillations in stochastic gravitational waves

   Maxim Dvornikov (IZMIRAN)🇷🇺

   We study neutrino flavor oscillations in a plane gravitational wave (GW) with circular polarization. For this purpose we use the solution of the Hamilton-Jacobi equation to get the contribution of GW to the effective Hamiltonian for the neutrino mass eigenstates. Then, considering stochastic GWs, we derive the equation for the density matrix for flavor neutrinos and analytically solve it in the two flavors approximation. The equation for the density matrix for the three neutrino flavors is also derived and solved numerically. In both cases of two and three neutrino flavors, we predict the ratios of fluxes of different flavors at a detector for cosmic neutrinos with relatively low energies owing to the interaction with such a GW background. The obtained results are compared with the recent observation of the flavor content of the astrophysical neutrino fluxes.

   hep-phastro-ph.HEgr-qcPRD(2019)·23 citations
8. 08*

   On the Role of the ${\nu }_{\tau }$ Appearance in DUNE in Constraining Standard Neutrino Physics and Beyond

   Anish Ghoshal🇮🇹 · Alessio Giarnetti🇮🇹 · Davide Meloni🇮🇹

   We consider the ${\nu }_{\mu }\to {\nu }_{\tau }$ appearance channel in the future Deep Underground Neutrino Experiment (DUNE) which offers a good statistics of the ${\nu }_{\tau }$ sample. In order to measure its impact on constraining the oscillation parameters, we consider several assumptions on the efficiency for ${\nu }_{\tau }$ charged-current signal events (with subsequent $\tau \to e$ decay) and the related backgrounds and study the effects of various systematic uncertainties. Two different neutrino fluxes have been considered, namely a CP-violation optimized flux and a ${\nu }_{\tau }$ optimized flux. Our results show that the addition of the ${\nu }_{\mu }\to {\nu }_{\tau }$ appearance channel does not reduce the current uncertainties on the standard 3-$\nu$ oscillation parameters while it can improve in a significant way the sensitivity to the Non-Standard Interaction parameter $|{ϵ}_{\mu \tau }|$ and to the new mixing angle ${\theta }_{34}$ of a sterile neutrino model of the $3+1$ type.

   hep-phJHEP(2019)·45 citations
9. 09*

   On the effect of resonances in the quark-photon vertex

   Ángel S. Miramontes🇦🇹 · Hèlios Sanchis-Alepuz🇦🇹

   A calculation of hadronic timelike form factors in the Poincaré-covariant Bethe-Salpeter formalism necessitates knowing the analytic structure of the non-perturbative quark-photon vertex in the context of the Poincaré-covariant Bethe-Salpeter formalism. We include, in the interaction between quark and antiquark, the possibility of non-valence effects by introducing pions as explicit degrees of freedom. These encode the presence of intermediate resonances in the Bethe-Salpeter interaction kernel. We calculate the vertex for real as well as complex photon momentum. We show how the vertex reflects now the correct physical picture, with the rho resonance appearing as a pole in the complex momentum plane. A multiparticle branch cut for values of the photon momentum from $-4m_{\pi }^2$ to $-\infty$ develops. This calculation represents an essential step towards the calculation of timelike form factors in the Bethe-Salpeter approach.

   hep-phEPJA(2019)·34 citations
10. 10*

    Direct detection of primordial black hole relics as dark matter

    Benjamin V. Lehmann🇺🇸 · Christian Johnson🇺🇸 · Stefano Profumo🇺🇸 · Thomas Schwemberger🇺🇸

    If dark matter is composed of primordial black holes, such black holes can span an enormous range of masses. A variety of observational constraints exist on massive black holes, and black holes with masses below $10^{15}\mathrm{g}$ are often assumed to have completely evaporated by the present day. But if the evaporation process halts at the Planck scale, it would leave behind a stable relic, and such objects could constitute the entirety of dark matter. Neutral Planck-scale relics are effectively invisible to both astrophysical and direct detection searches. However, we argue that such relics may typically carry electric charge, making them visible to terrestrial detectors. We evaluate constraints and detection prospects in detail, and show that if not already ruled out by monopole searches, this scenario can be largely explored within the next decade using existing or planned experimental equipment. A single detection would have enormous implications for cosmology, black hole physics, and quantum gravity.

    hep-phastro-ph.COJCAP(2019)·91 citations
11. 11*

    Constraints on Lorentz Invariance Violations from Gravitational Wave Observations

    Anuradha Samajdar (for the LIGO Scientific Collaboration and Virgo Collaboration)🇳🇱

    Using a deformed dispersion relation for gravitational waves, Advanced LIGO and Advanced Virgo have been able to place constraints on violations of local Lorentz invariance as well as the mass of the graviton. We summarise the method to obtain the current bounds from the 10 significant binary black hole detections made during the first and second observing runs of the above detectors.

    ↳ gr-qchep-ph3 citations
12. 12*

    Viscosity calculations from Hadron Resonance Gas model: Finite size effect

    Snigdha Ghosh🇮🇳 · Subhasis Samanta🇮🇳 · Sabyasachi Ghosh🇮🇳 · Hiranmaya Mishra🇮🇳

    We have attempted to review on microscopic calculation of transport coefficients like shear and bulk viscosities in the framework of hadron resonance gas model, where a special attention is explored on the effect of finite system size. The standard expressions of transport coefficients, obtained from relaxation time approximation of kinetic theory or diagrammatic Kubo-type formalism, carry mainly two temperature dependent components -- thermodynamical phase space and relaxation time of medium constituent. Owing to quantum effect of finite system size, thermodynamical phase space can be reduced as its momentum distribution will be started from some finite lower momentum cut-off instead of zero momentum. On the other hand, relaxation time of hadrons can also face finite size effect by considering only those relaxation scales, which are lower than the system size. Owing to these phenomenological issues, we have proposed a system size dependent upper bound of transport coefficients for ideal HRG model, whose qualitative technique may also be applicable in other models. This finite size prescription may guide to shorten the broad numerical band, within which earlier estimated values of transport coefficients for hadronic matter are located. It is also suspected that the hadronic matter may not be far from the (nearly) perfect fluid nature like the quark gluon plasma.

    ↳ nucl-thhep-phnucl-exIJMPE(2019)·8 citations
13. 13*

    Deuteron-like heavy dibaryons from Lattice QCD

    Parikshit Junnarkar🇮🇳 · Nilmani Mathur🇮🇳

    We report the first lattice quantum chromodynamics (QCD) study of deuteron($np$)-like dibaryons with heavy quark flavours. These include particles with following dibaryon structures and valence quark contents: ${\Sigma }_c{\Xi }_{cc}(uucucc)$, ${\Omega }_c{\Omega }_{cc}(sscscc)$, ${\Sigma }_b{\Xi }_{bb}(uububb)$, ${\Omega }_b{\Omega }_{bb}(ssbsbb)$ and ${\Omega }_{ccb}{\Omega }_{cbb}(ccbcbb)$, and with spin ($J$)-parity ($P$), $J^P\equiv 1^{+}$. Using a state-of-the art lattice QCD calculation, after controlling relevant systematic errors, we unambiguously find that the ground state masses of dibaryons ${\Omega }_c{\Omega }_{cc}(sscscc)$, ${\Omega }_b{\Omega }_{bb}(ssbsbb)$ and ${\Omega }_{ccb}{\Omega }_{cbb}(ccbcbb)$ are below their respective two-baryon thresholds, suggesting the presence of bound states which are stable under strong and electromagnetic interactions. We also predict their masses precisely. For dibaryons ${\Sigma }_c{\Xi }_{cc}(uucucc)$, and ${\Sigma }_b{\Xi }_{bb}(uububb)$, we could not reach to a definitive conclusion about the presence of any bound state due to large systematics associated with these states. We also find that the binding of these dibaryons becomes stronger as they become heavier in mass. This study also opens up the possibility of the existence of many other exotic nuclei, which can be formed through the fusion of heavy baryons, similar to the formation of nuclei of elements in the Periodic Table.

    ↳ hep-lathep-exhep-phnucl-ex+1PRL(2019)·73 citations
14. 14*

    Novel signatures of dark matter in laser-interferometric gravitational-wave detectors

    H. Grote🇬🇧 · Y. V. Stadnik🇩🇪

    Dark matter may induce apparent temporal variations in the physical "constants", including the electromagnetic fine-structure constant and fermion masses. In particular, a coherently oscillating classical dark-matter field may induce apparent oscillations of physical constants in time, while the passage of macroscopic dark-matter objects (such as topological defects) may induce apparent transient variations in the physical constants. In this paper, we point out several new signatures of the aforementioned types of dark matter that can arise due to the geometric asymmetry created by the beam-splitter in a two-arm laser interferometer. These new signatures include dark-matter-induced time-varying size changes of a freely-suspended beam-splitter and associated time-varying shifts of the main reflecting surface of the beam-splitter that splits and recombines the laser beam, as well as time-varying refractive-index changes in the freely-suspended beam-splitter and time-varying size changes of freely-suspended arm mirrors. We demonstrate that existing ground-based experiments already have sufficient sensitivity to probe extensive regions of unconstrained parameter space in models involving oscillating scalar dark-matter fields and domain walls composed of scalar fields. In the case of oscillating dark-matter fields, Michelson interferometers $-$ in particular, the GEO600 detector $-$ are especially sensitive. The sensitivity of Fabry-Perot-Michelson interferometers, including LIGO, VIRGO and KAGRA, to oscillating dark-matter fields can be significantly increased by making the thicknesses of the freely-suspended Fabry-Perot arm mirrors different in the two arms. We also discuss how small-scale Michelson interferometers, such as the Fermilab holometer, could be used to perform resonant narrowband searches for oscillating dark-matter fields with enhanced sensitivity to dark matter.

    ↳ astro-ph.IMhep-phphysics.opticsPRResearch(2019)·156 citations
15. 15*

    Progress towards characterizing ultrahigh energy cosmic ray sources

    Marco Stein Muzio🇺🇸 · Michael Unger🇩🇪 · Glennys R. Farrar🇺🇸

    We use a multimessenger approach to constrain realistic mixed composition models of ultrahigh energy cosmic ray sources using the latest cosmic ray, neutrino, and gamma-ray data. We build on the successful Unger-Farrar-Anchordoqui 2015 (UFA15) model which explains the shape of the spectrum and its complex composition evolution via photodisintegration of accelerated nuclei in the photon field surrounding the source. We explore the constraints which can currently be placed on the redshift evolution of sources and the temperature of the photon field surrounding the sources. We show that a good fit is obtained to all data either with a source which accelerates a narrow range of nuclear masses or a Milky Way-like mix of nuclear compositions, but in the latter case the nearest source should be 30-50 Mpc away from the Milky Way in order to fit observations from the Pierre Auger Observatory. We also ask whether the data allow for a subdominant purely protonic component at UHE in addition to the primary UFA15 mixed composition component. We find that such a two-component model can significantly improve the fit to cosmic ray data while being compatible with current multimessenger data.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2019)·87 citations
16. 16*

    Lorentz violation constraints with astroparticle physics

    H. Martínez-Huerta🇧🇷

    Astroparticle physics has recently reached a new status of precision due to the construction of new observatories, operating innovative technologies and the detection of large numbers of events and sources. The precise measurements of cosmic and gamma rays can be used as a test for fundamental physics, such as the Lorentz invariance violation (LV). Although LV signatures are expected to be small, the very high energies and long distances that astrophysical sources involve, lead to an unprecedented opportunity for this task. In this summary, exclusion limits results are presented from different types of astrophysical LV tests through the generic modification of the particle dispersion relation in the photon sector through the pair production threshold shifts and photon decay. Some perspectives for the next generations of gamma-ray telescopes are also addressed

    ↳ astro-ph.HEhep-ph4 citations
17. 17*

    Resonant Decay of Gravitational Waves into Dark Energy

    Paolo Creminelli🇮🇹 · Giovanni Tambalo🇮🇹 · Filippo Vernizzi🇫🇷 · Vicharit Yingcharoenrat🇮🇹

    We study the decay of gravitational waves into dark energy fluctuations $\pi$, taking into account the large occupation numbers. We describe dark energy using the effective field theory approach, in the context of generalized scalar-tensor theories. When the $m_3^3$ (cubic Horndeski) and ${\tilde{m}}_4^2$ (beyond Horndeski) operators are present, the gravitational wave acts as a classical background for $\pi$ and modifies its dynamics. In particular, $\pi$ fluctuations are described by a Mathieu equation and feature instability bands that grow exponentially. Focusing on the regime of small gravitational-wave amplitude, corresponding to narrow resonance, we calculate analytically the produced $\pi$, its energy and the change of the gravitational-wave signal. The resonance is affected by $\pi$ self-interactions in a way that we cannot describe analytically. This effect is very relevant for the operator $m_3^3$ and it limits the instability. In the case of the ${\tilde{m}}_4^2$ operator self-interactions can be neglected, at least in some regimes. The modification of the gravitational-wave signal is observable for $3\times 10^{-20}\lesssim {\alpha }_{\mathrm{H}}\lesssim 10^{-17}$ with a LIGO/Virgo-like interferometer and for $10^{-16}\lesssim {\alpha }_{\mathrm{H}}\lesssim 10^{-10}$ with a LISA-like one.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2019)·60 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.