Wed·Dec 26, 2018Wednesday·December 26, 2018

1. 01*

   Gravitational particle creation for dark matter and reheating

   Soichiro Hashiba🇯🇵 · Jun'ichi Yokoyama🇯🇵

   The purely gravitational dark matter (PGDM) which interacts with the standard model particles only by gravitational interaction has recently been discussed. Due to its feeble interaction, PGDM may be produced mainly by the gravitational particle creation, which plays an important role in the reheating after kinetically driven inflation and some potential-driven inflation without subsequent inflaton oscillating phase. Therefore, we consider the possibility of the gravitational reheating model which can also explain the present PGDM density at the same time. We consider a model where two massive scalar fields are incorporated into the standard model besides the inflation sector. We show that the gravitational particle creation prevails over the thermal creation --- the freeze-in process --- and it can actually explain the reheating and the present abundance of dark matter if one of the scalar particles is as heavy as the Hubble parameter during inflation $\sim 10^{13}$ GeV and finally decays into radiation via sufficiently weak coupling, and the other is a stable PGDM with its mass of the order of $10^3$ GeV.

   hep-phastro-ph.COgr-qcPRD(2019)·84 citations
2. 02*

   Multiplicity spectra in $e^{+}{e}^{-}$ and $\overline{p}p$ collisions in terms of Tsallis and Weibull distributions

   S. Sharma🇮🇳 · M. Kaur🇮🇳 · S. Thakur🇮🇳

   Charged hadron production in the $e^{+}{e}^{-}$ annihilations at 91 to 206 GeV in full phase space and in $\overline{p}p$ collisions at 200 to 900~GeV collision energies are studied using non-extensive Tsallis and stochastic Weibull probability distributions.~The Tsallis distribution shows better description of the data than the Weibull distribution. The 2-jet modification of the statistical distribution is applied to describe $e^{+}{e}^{-}$ data.~The main features of these distributions can be described by a two-component model with soft, collective interactions at low transverse energy and hard, constituent interactions dominating at high transverse energy.~This modification is found to give much better description than a full-sample fit, and again Tsallis function is found to better describe the data than the Weibull one pointing at the non-extensive character of the multiparticle production process.

   hep-phIJMPE(2019)·4 citations
3. 03*

   Jet shape modifications at the LHC energies by JEWEL

   Renzhuo Wan🇨🇳 · Lei Ding🇨🇳 · Xi Gui🇨🇳 · Fan Yang🇨🇳 · Shuang Li🇨🇳 · Daicui Zhou🇨🇳

   Jet shape measurements are strongly suggested to explore the microscopic evolution mechanism of parton-medium interaction in ultra-relativistic heavy-ion collisions. In this paper, jet shape modifications are quantified by fragmentation function $F(z)$, relative momentum $p_T^{rel}$, density of charged particles $\rho (r)$, jet angularity $girth$, jet momentum dispersion $p_T^{Disp}$ and $LeSub$ for proton-proton collisions at $900GeV$, $5.02TeV$, $7TeV$ and $13TeV$, as well as for lead-lead collisions at $2.76TeV$ and $5.02TeV$. A differential jet shape parameters $D_{girth}$ is proposed and studied at smaller-radius jet $r<0.3$. The results indicate that medium effect is dominant for jet shape modifications, which is less dependent on center of mass energy. The jet fragmentation is enhanced significantly at very low $z<0.02$ and fragmented jet constituents are spread to larger jet-radius linearly for $p_T^{rel}<1$. The waveform attenuate phenomena is observed in $p_T^{rel}$, $girth$ and $D_{girth}$ distributions. The comparison results on $D_{girth}$ from $pp$ to $Pb+Pb$ where the wave-like distribution in $pp$ collision is ahead of $Pb+Pb$ collisions in small jet-radius intervals, is interesting to hint the medium effect.

   hep-phCPC(2019)·7 citations
4. 04*

   A Minimal System Including Weak Sphalerons for Investigating the Evolution of Matter Asymmetries and Hypermagnetic Fields

   S. Rostam Zadeh🇮🇷 · S. S. Gousheh🇮🇷

   We study simultaneous evolution of large scale hypermagnetic fields and the asymmetries of quarks, leptons and Higgs boson in the temperature range from 10TeV to 100GeV. Above 10TeV, we identify all of the major fast interactions and use the associated conservation laws as constraints on the initial conditions at 10TeV. Below 10TeV, we identify the major processes which fall out of equilibrium or emerge as non-negligible processes and derive the relevant evolution equations. These include the Abelian anomalies which violate fermion numbers, direct and inverse Higgs decays that change the chiralities of fermions, and weak sphalerons which violate the left-handed fermion numbers. We also consider the contributions of all fermionic chemical potentials to the UY(1) Chern-Simons term which affects the evolution through the AMHD equations. Thus, we present a minimal set of self-consistent initial conditions and evolution equations which respect all constraints coming from conservation laws, fast processes and charge neutrality of the plasma. We solve the coupled evolution equations and find that initial large hypermagnetic field can produce matter asymmetries starting from zero initial value, and vice versa provided an initial seed of hypermagnetic field is present and the rate of the electron Yukawa processes is lower. We find that our model yields acceptable values for baryon asymmetry and magnetic field. However, the scale of the magnetic field obtained is much smaller than the observational data, even when the turbulence driven inverse cascade mechanism in the broken phase is taken into account.

   hep-phastro-ph.COPRD(2019)·12 citations
5. 05*

   New charged resonance $Z_c^{-}(4100)$: the spectroscopic parameters and width

   H. Sundu🇹🇷 · S. S. Agaev🇦🇿 · K. Azizi🇹🇷

   The mass, coupling and width of the newly observed charged resonance $Z_c^{-}(4100)$ are calculated by treating it as a scalar four-quark system with a diquark-antidiquark structure. The mass and coupling of the state $Z_c^{-}(4100)$ are calculated using the QCD two-point sum rules. In these calculations we take into account contributions of the quark, gluon and mixed condensates up to dimension ten. The spectroscopic parameters of $Z_c^{-}(4100)$ obtained by this way are employed to study its $S$-wave decays to ${\eta }_c(1S){\pi }^{-}$, ${\eta }_c(2S){\pi }^{-}$, $D^0{D}^{-}$, and $J/\psi {\rho }^{-}$ final states. To this end, we evaluate the strong coupling constants corresponding to the vertices $Z_c{\eta }_c(1S){\pi }^{-}$, $Z_c{\eta }_c(2S){\pi }^{-}$, $Z_c{D}^0{D}^{-}$, and $Z_{c}J/\psi {\rho }^{-}$ respectively. The couplings $g_{Z_c{\eta }_{c1}\pi }$, $g_{Z_c{\eta }_{c2}\pi }$ , and $g_{Z_{c}DD}$ are computed by means of the QCD three-point sum rule method, whereas $g_{Z_{c}J/\psi \rho }$ is obtained from the QCD light-cone sum rule approach and soft-meson approximation. Our results for the mass $m=(4080\pm 150)\mathrm{MeV}$ and total width $\Gamma =(147\pm 19)\mathrm{MeV}$ of the resonance $Z_c^{-}(4100)$ are in excellent agreement with the existing LHCb data.

   hep-phhep-exhep-latEPJC(2019)·41 citations
6. 06*

   On the violent preheating in the mixed Higgs-$R^2$ inflationary model

   Minxi He🇯🇵 · Ryusuke Jinno🇰🇷 · Kohei Kamada🇯🇵 · Seong Chan Park🇰🇷 · Alexei A. Starobinsky🇯🇵 · Jun'ichi Yokoyama🇯🇵

   It has been argued that the mixed Higgs-$R^2$ model acts as the UV extension of the Higgs inflation, pushing up its cut-off scale in the vacuum close up to the Planck scale. In this letter, we study the inflaton oscillation stage after inflation, focusing on the effective mass of the phase direction of the Higgs field, which can cause a violent preheating process. We find that the "spikes" in the effective mass of the phase direction observed in the Higgs inflation still appear in the mixed Higgs-$R^2$ model. While the spikes appear above the cut-off scale in the Higgs-only case, they appear below the cut-off scale when the model is extended with $R^2$ term though reheating cannot be completed in the violent particle production regime since the spikes get milder.

   hep-phastro-ph.COgr-qchep-thPLB(2019)·85 citations
7. 07*

   $b-\tau$ Yukawa Unification in SUSY SU(5) with Mirage Mediation: LHC and Dark Matter Implications

   Shabbar Raza🇵🇰 · Qaisar Shafi🇺🇸 · Cem Salih Un🇹🇷

   We consider a class of $b-\tau$ Yukawa unified Supersymmetric (SUSY) $SU(5)$ GUTs, in which the asymptotic gaugino $M_{1,2,3}$ masses are generated through a combination of gravity and mirage mediated supersymmetry breaking. Due to the contributions from mirage mediation, $M_3$ is always lighter than M_{1} and M_{2}, and consequently for the range of asymptotic masses considered, the gluino mass at low scale is bounded from above at about 4 TeV. We realize two different regions, one in which the MSSM $\mu -$term is less than about 3 TeV. This region yields a stop mass up to 5 TeV, and the stop mass is nearly degenerate with the LSP neutralino for mass around 0.8 to 1.7 TeV. A stau mass can be realized up to about 5 TeV, and the stau mass is approximately degenerate with the LSP neutralino for mass around 2 to 3 TeV. In addition, an A-funnel solution $m_A$ with mass $\sim 1.4-1.8$ TeV is realized. A second region, on the other hand, arises for gluino around 1.1 TeV. The $\mu -$term is rather large than 20 TeV, and the LSP neutralino is a bino-wino mixture. The gluino mass ($\sim 0.8-1.2$ TeV) is nearly degenerate with the LSP neutralino mass and hence, the gluino-neutralino coannihilation processes play a role in reducing the relic abundance of LSP neutralino down to ranges allowed by the current WMAP measurements. The two regions above can be distinguished through the direct detection experiments. The first region with relatively low $\mu$ values yields Higgsino-like DM, whose scattering on the nucleus typically has a large cross-section. We find that such solutions are still allowed by the current results from the LUX experiment, and they will be severely tested by the LUX-Zeplin experiment. The second region contains bino-wino DM whose scattering cross-section is relatively low. These solutions are harder to rule out in the foreseeable future.

   hep-phJHEP(2019)·19 citations
8. 08*

   Safe Trinification

   Zhi-Wei Wang🇩🇰 · Abdulrahim Al Balushi🇨🇦 · Robert Mann🇨🇦 · Hao-Miao Jiang🇨🇦

   In this work, we provide a UV safe Trinification theory in which the Standard Model is embedded. Using recently developed large number-of-flavor techniques, safety is achieved by adding to the theory gauged vector-like fermions. We find that all gauge, scalar quartic, and Yukawa couplings achieve an interacting ultraviolet fixed point below the Planck scale. We find renormalization group flow solutions matching the Standard Model in the IR, indicating a truly UV completion of the Standard Model. Imposing constraints that realistic Higgs, top, bottom, tau and reasonable neutrino masses are recovered, we find the set of allowed solutions to be quite restrictive. Furthermore, the symmetry breaking scale is predicted to be around 10 TeV, making this model vulnerable to experiment.

   hep-phPRD(2019)·26 citations
9. 09*

   Nonlocal generalization of Galilean theories and gravity

   Luca Buoninfante🇮🇹 · Gaetano Lambiase🇮🇹 · Masahide Yamaguchi🇯🇵

   In this paper we propose a wider class of symmetries including the Galilean shift symmetry as a subclass. We will show how to construct ghost-free nonlocal actions, consisting of infinite derivative operators, which are invariant under such symmetries, but whose functional form is not simply given by exponentials of entire functions. Motivated by this, we will consider the case of a scalar field and discuss the pole structure of the propagator which has infinitely many complex conjugate poles, but satisfies the tree-level unitarity. We will also consider the possibility to construct UV complete Galilean theories by showing how the ultraviolet behavior of loop integrals can be ameliorated. Moreover, we will consider kinetic operators respecting the same symmetries in the context of linearized gravity. In such a scenario, the graviton propagator turns out to be ghost-free and the spacetime metric generated by a point-like source is nonsingular. These new nonlocal models can be seen as an infinite derivative generalization of Lee-Wick theories and open a new branch of nonlocal theories.

   ↳ hep-thgr-qchep-phPRD(2019)·36 citations
10. 10*

    Spontaneous dark-matter mass generation along cosmological attractors in string theory

    Thibaut Coudarchet🇫🇷 · Lucien Heurtier🇺🇸 · Herve Partouche🇫🇷

    We propose a new scenario for generating a relic density of non-relativistic dark matter in the context of heterotic string theory. Contrary to standard thermal freeze-out scenarios, dark-matter particles are abundantly produced while still relativistic, and then decouple from the thermal bath due to the sudden increase of their mass above the universe temperature. This mass variation is sourced by the condensation of an order-parameter modulus, which is triggered when the temperature T(t) drops below the supersymmetry breaking scale M(t), which are both time-dependent. A cosmological attractor mechanism forces this phase transition to take place, in an explicit class of heterotic string models with spontaneously broken supersymmetry, and at finite temperature.

    ↳ hep-thgr-qchep-phJHEP(2019)·8 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.