Fri·Dec 28, 2018Friday·December 28, 2018

1. 01*

   Non-thermal Dark Matter from Modified Early Matter Domination

   Rouzbeh Allahverdi🇺🇸 · Jacek K. Osiński🇺🇸

   Thermal freeze-out or freeze-in during a period of early matter domination can give rise to the correct dark matter abundance for $⟨{\sigma }_{\mathrm{ann}}v{⟩}_{\mathrm{f}}<3\times 10^{-26}$ cm${}^3$ s${}^{-1}$. In the standard scenario, a single field that behaves like matter drives the early matter dominated era. However, in realistic models, this epoch may involve more than one field. In this paper, we study the effect of such a modification on the production of dark matter during early matter domination. We show that even a subdominant second field that decays much faster than the dominant one can considerably enhance the temperature of the universe during an early matter-dominated phase. This in turn affects dark matter production via freeze-out/in and opens up the allowed parameter space toward significantly larger dark matter masses. As a result, one can comfortably obtain the correct relic abundance for PeV-scale dark matter for reheating temperatures at or below 10 GeV.

   hep-phastro-ph.COPRD(2019)·25 citations
2. 02*

   The top quark charge asymmetry in $t\bar{t}\gamma$ production at the LHC

   Jonas Bergner🇩🇪 · Markus Schulze🇩🇪

   We consider the top quark charge asymmetry in the process $pp\to t\bar{t}+\gamma$ at the 13 TeV LHC. The genuine tree level asymmetry in the $q\bar{q}$ channel is large with about -12%. However, the symmetric $gg$ channel, photon radiation off top quark decay products, and higher order corrections wash out the asymmetry and obscure its observability. In this work, we investigate these effects at next-to-leading order QCD and check the robustness of theoretical predictions. We find a sizable perturbative correction and discuss its origins and implications. We also study dedicated cuts for enhancing the asymmetry and show that a measurement is possible with an integrated luminosity of 150 fb${}^{-1}$.

   hep-phEPJC(2019)·26 citations
3. 03*

   A minimal non-supersymmetric SO(10) model with Peccei--Quinn symmetry

   Sofiane M. Boucenna🇸🇪 · Tommy Ohlsson🇸🇪 · Marcus Pernow🇸🇪

   We present a minimal non-supersymmetric SO(10) GUT breaking directly to the Standard Model gauge group. Precise gauge coupling unification is achieved due to the presence of two color-octet scalars, one of which is accessible to LHC searches. Proton lifetime is predicted to be below $4.5\times 10^{34}$ years, which is within the projected five-year sensitivity of the proposed Hyper-Kamiokande experiment. We find that the Standard Model observables are reproduced to a reasonable accuracy in a numerical fit, which also predicts the unknown neutrino parameters. Finally, the two scalar representations stabilize the electroweak vacuum and the dark matter is comprised of axions.

   hep-phPLB(2019)·24 citations
4. 04*

   Implementing the inverse type-II seesaw mechanism into the 3-3-1 model

   Carlos Antônio de Sousa Pires🇧🇷 · Felipe Ferreira de Freitas🇨🇳 · Jing Shu🇨🇳 · Li Huang🇨🇳 · Pablo Wagner Vasconcelos Olegário🇧🇷

   After the LHC is turning on and accumulating more data, the TeV scale seesaw mechanisms for small neutrino masses in the form of inverse seesaw mechanisms are gaining more and more attention once they provide neutrino masses at sub-eV scale and can be probed at the LHC. Here we restrict our investigation to the inverse type II seesaw case and implement it into the framework of the 3-3-1 model with right-handed neutrinos. As interesting result, the mechanism provides small masses to both the standard neutrinos as well as to the right-handed ones. Its best signature are the doubly charged scalars which are sextet by the 3-3-1 symmetry. We investigate their production at the LHC through the process $\sigma (pp\to Z^{\ast },{\gamma }^{\ast },Z^{\prime }\to {\Delta }^{++}{\Delta }^{--})$ and their signal through four leptons final state decay channel.

   hep-phPLB(2019)·28 citations
5. 05*

   Higgs as heavy-lifted physics during inflation

   Yi-Peng Wu🇯🇵

   Signals of heavy particle production during inflation are encoded as non-analytic momentum scaling in primordial non-Gaussianity. These non-analytic signatures can be sourced by Standard Model particles with a modified Higgs scale uplifted by the slow-roll dynamics of inflation. We show that such a lifting mechanism becomes more efficient with the presence of a strong Higgs-inflaton mixing, where the Higgs mass scale is further increased by a small speed of sound in the effective theory of inflation. As a primary step towards detecting new particles in the cosmological collider program, non-Gaussianity due to heavy Higgs production in the strong-mixing regime can act as important background signals to be tested by future cosmological surveys.

   hep-phJHEP(2019)·59 citations
6. 06*

   Quantum Field Theory and the Electroweak Standard Model

   Alexander Bednyakov🇷🇺

   These lecture notes cover the basics of Quantum Field Theory (QFT) and peculiarities in the construction of the Electroweak (EW) sector of the Standard Model (SM). In addition, the present status, issues, and prospects of the SM are discussed.

   hep-phCERN Yellow Rep.School Proc.(2019)·3 citations
7. 07*

   Saha ionization equation in early universe

   Aritra Das🇮🇳 · Ritesh Ghosh🇮🇳 · S. Mallik🇮🇳

   The Saha equation follows from thermal equilibrium of matter and radiation. We discuss this problem of equilibrium in the early universe, when matter consists mostly of electrons, protons and hydrogen atoms. Taking H-atoms in their ground state only and applying the real time formulation of thermal field theory, we calculate the difference of ionization and recombination rates, which controls the equilibration of H-atoms. This rate is compared with the expansion rate of the universe at different temperatures.

   hep-phApJ(2019)·0 citations
8. 08*

   Basics of doubly heavy tetraquarks

   A. Valcarce🇪🇸 · J.-M. Richard🇫🇷 · J. Vijande🇪🇸

   We outline the most important results regarding the stability of doubly heavy tetraquarks $QQ\bar{q}\bar{q}$ with an adequate treatment of the four-body dynamics. We consider both color-mixing and spin-dependent effects. Our results are straightforwardly applied to the case of all-heavy tetraquarks $QQ\bar{Q}\bar{Q}$. We conclude that the stability is favored in the limit $M_Q/m_q\gg 1$ pointing to the stability of the $bb\bar{u}\bar{d}$ state and the instability of all-heavy tetraquarks.

   hep-phnucl-thJ.Phys.Conf.Ser.(2019)·0 citations
9. 09*

   Study of $t\bar{t}H$ production with $H\to b\bar{b}$ at the HL-LHC

   A. J. Costa🇬🇧 · A. L. Carvalho🇵🇹 · R. Gonçalo🇵🇹 · P. Muiño🇵🇹 · A. Onofre🇵🇹

   A feasibility study for an experimental analysis searching for $t\bar{t}H(H\to b\bar{b})$ production at the LHC and its high luminosity phase is presented in this note. Unlike search strategies currently being used in experimental collaborations, the present analysis exploits jet substructure techniques and focuses on the reconstruction of boosted Higgs bosons, to obtain sensitivity to the signal in a simple cut-based analysis. The $t\bar{t}+$ jets background may be constrained in the proposed analysis through a control region with very small signal contamination. Using this analysis strategy, the $t\bar{t}H(H\to b\bar{b})$ process could be observed at the LHC, in the semi-leptonic channel alone, with a significance of $5.41\pm 0.12$ for $\mathcal{L}=300\text{mbox}{fb}^{-1}$. For the same integrated luminosity, in the High Luminosity LHC scenario with an upgraded detector, a significance of $6.13\pm 0.11$ may be obtained. The top Yukawa coupling could be measured with a 35\% uncertainty using $\mathcal{L}=300\text{mbox}{fb}^{-1}$ of LHC data and of 17\% at the HL-LHC scenario with $\mathcal{L}=3000\text{mbox}{fb}^{-1}$. In the same luminosity scenarios, the signal strength is equally expected to have a 18$\%$ and 5$\%$ uncertainty, respectively. Finally, it was found that re-clustered jets may be used without loss of efficiency.

   hep-ph2 citations
10. 10*

    Rare fluctuations of the $S$-matrix at NLO in QCD

    Wenchang Xiang🇨🇳 · Yanbing Cai🇨🇳 · Mengliang Wang🇨🇳 · Daicui Zhou🇨🇳

    We calculate the rare fluctuations of the $S$-matrix on top of the full next-to-leading order corrections in the center of mass frame. The relevant result in the saturation regime shows that the exponential factor of the $S$-matrix is $\sqrt{2}$ as large as the result which emerges when the rare fluctuation effects are taken into account. We find that the factor of $\sqrt{2}$ change of the exponential factor is induced by the gluon loop corrections which compensate part of rapidity decrease of the $S$-matrix made by quark loops and lead to the rare fluctuations becoming important again. To ensure the relevant results of the $S$-matrix are independent of the frame choice, the rare fluctuations of the $S$-matrix are also derived in a general frame. It is found that all the results are consistent with each other in both frames.

    hep-phPRD(2019)·8 citations
11. 11*

    The Spinless Relativistic Hellmann Problem

    Wolfgang Lucha🇦🇹 · Franz F. Schöberl🇦🇹

    We compile some easily deducible information on the discrete eigenvalue spectra of spinless Salpeter equations encompassing, besides a relativistic kinetic term, interactions which are expressible as superpositions of an attractive Coulomb potential and an either attractive or repulsive Yukawa potential and, hence, generalizations of the Hellmann potential employed in several areas of science. These insights should provide useful guidelines to all attempts of finding appropriate descriptions of bound states by (semi-) relativistic equations of motion.

    hep-phmath-phmath.MPnucl-th+1Int.J.Mod.Phys.A(2019)·3 citations
12. 12*

    Signatures of Synchrotron Radiation from the Annihilation of Dark Matter at the Galactic Centre

    Avik Paul🇮🇳 · Debasish Majumdar🇮🇳 · Amit Dutta Banik🇮🇳

    We propose a fermionic dark matter model by extending Standard Model with a Dirac fermion and a real pseudoscalar. The fermion dark matter particle interacts with the Standard Model sector via the Higgs portal through a dimension five interaction term as also through a pseudoscalar interaction term. The parameter space of the model is then constrained by using the vacuum stability and perturbativity condition as also with the LHC constraints. They are finally constrained by the PLANCK results for dark matter relic densities. The direct detection limits are then ensured to have satisfied by the model. We then explore within the framework of the model, the possible signatures of synchrotron radiation from the annihilations of dark matter in the Galactic Centre region when the end product is $e^{+}{e}^{-}$. We consider the observational data from the radio telescopes namely SKA, GMRT and Jodrell Bank telescopes and compare our calculated synchrotron flux density with them and also with the results predicted by these experiments. We predict that if the low frequency radio telescopes like GMRT, SKA operate at the peak frequencies obtained from our calculations should get a better r.m.s sensitivity.

    hep-phJCAP(2019)·5 citations
13. 13*

    Form factors of two-hadron states from a covariant finite-volume formalism

    Alessandro Baroni🇺🇸 · Raúl A. Briceño🇺🇸 · Maxwell T. Hansen🇨🇭 · Felipe G. Ortega-Gama🇺🇸

    In this work we develop a Lorentz-covariant version of the previously derived formalism for relating finite-volume matrix elements to $\text{2}+\mathcal{J}\to \text{2}$ transition amplitudes. We also give various details relevant for the implementation of this formalism in a realistic numerical lattice QCD calculation. Particular focus is given to the role of single-particle form factors in disentangling finite-volume effects from the triangle diagram that arise when $\mathcal{J}$ couples to one of the two hadrons. This also leads to a new finite-volume function, denoted $G$, the numerical evaluation of which is described in detail. As an example we discuss the determination of the $\pi \pi +\mathcal{J}\to \pi \pi$ amplitude in the $\rho$ channel, for which the single-pion form factor, $F_{\pi }(Q^2)$, as well as the scattering phase, ${\delta }_{\pi \pi }$, are required to remove all power-law finite-volume effects. The formalism presented here holds for local currents with arbitrary Lorentz structure, and we give specific examples of insertions with up to two Lorentz indices.

    ↳ hep-lathep-phPRD(2019)·65 citations
14. 14*

    Spinor-vector duality and sterile neutrinos in string derived models

    Alon E. Faraggi🇬🇧

    The MiniBooNE collaboration found evidence for the existence of sterile neutrinos, at a mass scale comparable to the active left-handed neutrinos. While sterile neutrinos arise naturally in large volume string scenarios, they are more difficult to accommodate in heterotic-string derived models that reproduce the GUT embedding of the Standard Model particles. Sterile neutrinos in heterotic-string models imply the existence of an additional Abelian gauge symmetry at low scales, possibly within reach of contemporary colliders. I discuss the construction of string derived Z' models that utilise the spinor-vector duality to guarantee that the extra $U(1{)}_{Z^{\prime }}$ symmetry can remain unbroken down to low scales.

    ↳ hep-thhep-phJ.Phys.Conf.Ser.(2020)·2 citations
15. 15*

    Melanopogenesis: Dark Matter of (almost) any Mass and Baryonic Matter from the Evaporation of Primordial Black Holes weighing a Ton (or less)

    Logan Morrison🇺🇸 · Stefano Profumo🇺🇸 · Yan Yu🇺🇸

    The evaporation of primordial black holes with a mass in the $1\mathrm{gram}\lesssim M_{\mathrm{PBH}}\lesssim$1000 kg range can lead to the production of dark matter particles of almost any mass in the range $0.1\mathrm{MeV}\lesssim m_{\mathrm{DM}}\lesssim 10^{18}$ GeV with the right relic density at very early times, $\tau \lesssim 10^{-10}$ s. We calculate, as a function of the primordial black holes mass and initial abundance, the combination of dark matter particle masses and number of effective dark degrees of freedom leading to the right abundance of dark matter today, whether or not evaporation stops around the Planck scale. In addition, since black hole evaporation can also lead to the production of a baryon asymmetry, we calculate where dark matter production and baryogenesis can concurrently happen, under a variety of assumptions: baryogenesis via grand unification boson decay, via leptogenesis, or via asymmetric co-genesis of dark matter and ordinary matter. Finally, we comment on possible ways to test this scenario.

    ↳ astro-ph.COastro-ph.HEhep-phJCAP(2019)·179 citations
16. 16*

    Searching for Bispectrum of Stochastic Gravitational Waves with Pulsar Timing Arrays

    Makoto Tsuneto🇺🇸 · Asuka Ito🇯🇵 · Toshifumi Noumi🇯🇵 · Jiro Soda🇯🇵

    We study how to probe bispectra of stochastic gravitational waves with pulsar timing arrays. The bispectrum is a key to probe the origin of stochastic gravitational waves. In particular, the shape of the bispectrum carries valuable information of inflation models. We show that an appropriate filter function for three point correlations enables us to extract a specific configuration of momentum triangles in bispectra. We also calculate the overlap reduction functions and discuss strategy for detecting the bispectrum with multiple pulsars.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2019)·13 citations
17. 17*

    Lattice study of supersymmetry breaking in N=2 supersymmetric quantum mechanics

    Daisuke Kadoh🇹🇭 · Katsumasa Nakayama🇯🇵

    We study supersymmetry breaking from a lattice model of N=2 supersymmetric quantum mechanics using the direct computational method proposed in arXiv:1803.07960. The vanishing Witten index is realized as a numerical result in high precision. The expectation value of Hamiltonian is evaluated for the double-well potential. Compared with the previous Monte-Carlo results, the obtained vacuum energy coincides with the known values within small errors for strong couplings. The instanton effect is also reproduced for weak couplings. The used computational method helps us to evaluate the effect of finite lattice spacings more precisely and to study the mechanism of non-perturbative supersymmetry breaking from lattice computations.

    ↳ hep-lathep-phhep-thNPB(2019)·8 citations
18. 18*

    On the cancellation of radiative corrections to the cross section of electron-proton scattering

    V.S. Fadin🇷🇺 · R.E. Gerasimov🇷🇺

    The largest radiative corrections to the cross section of electron-proton scattering at high energies are associated with emission of photons, real and virtual, by electron. They contain large logarithms coming from soft and collinear photons. Cancellation of the contributions of the soft photons to virtual and real corrections is well known. Less known is the fact that the contributions of the photons collinear to scattered electrons are also cancelled for the most of experiments. On the contrary, contributions of the photons collinear to initial electrons as a rule are not cancelled. It is shown, however, that these contributions are cancelled for the experimental set up suggested by A.A. Vorobev for measurement of proton radius.

    ↳ nucl-thhep-phPLB(2019)·7 citations
19. 19*

    On the absence of dark matter in dwarf galaxies surrounding the Milky Way

    Francois Hammer · Yanbin Yang · Jianling Wang · Frederic Arenou · Mathieu Puech · Hector Flores

    This paper presents an alternative scenario to explain the observed properties of the Milky Way dwarf Spheroidals (MW dSphs). We show that instead of resulting from large amounts of dark matter (DM), the large velocity dispersions observed along their lines of sight can be entirely accounted for by dynamical heating of DM-free systems resulting from MW tidal shocks. Such a regime is expected if the progenitors of the MW dwarfs are infalling gas-dominated galaxies. In this case, gas lost through ram-pressure leads to a strong decrease of self-gravity, a phase during which stars can radially expand, while leaving a gas-free dSph in which tidal shocks can easily develop. The DM content of dSphs is widely derived from the measurement of the dSphs self-gravity acceleration projected along the line of sight. We show that the latter strongly anti-correlates with the dSph distance from the MW, and that it is matched in amplitude by the acceleration caused by MW tidal shocks on DM-free dSphs. If correct, this implies that the MW dSphs would have negligible DM content, putting in question, e.g., their use as targets for DM direct searches, or our understanding of the Local Group mass assembly history. Most of the progenitors of the MW dSphs are likely extremely tiny dIrrs, and deeper observations and more accurate modeling are necessary to infer their properties as well as to derive star formation histories of the faintest dSphs.

    ↳ astro-ph.GAastro-ph.COgr-qchep-phApJ(2019)·20 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.