Mon·May 22, 2017Monday·May 22, 2017

1. 01*

   Proof of Factorization of ${\chi }_{cJ}$ Production in Non-Equilibrium QCD at RHIC and LHC in Color Singlet Mechanism

   Gouranga C Nayak🇺🇸

   Recently we have proved the factorization of NRQCD S-wave heavy quarkonium production at all orders in coupling constant. In this paper we extend this to prove the factorization of infrared divergences in ${\chi }_{cJ}$ production from color singlet $c\bar{c}$ pair in non-equilibrium QCD at RHIC and LHC at all orders in coupling constant. This can be relevant to study the quark-gluon plasma at RHIC and LHC.

   hep-phnucl-thJ.Theor.Appl.Phys.(2017)·24 citations
2. 02*

   Study on Fractal Characteristics in the e${}^{+}$e${}^{-}$ Collisions at $\sqrt{s_{NN}}=250$GeV

   Zeng Ting-ting🇨🇳 · Chen Gang🇨🇳 · Dong Zi-jian🇨🇳 · She Zhi-lei🇨🇳 · N. A. Ragab🇨🇳

   The fractal characteristics of multi-particle final state are first studied in the $e^{+}{e}^{-}$ collision of $\sqrt{s_{NN}}=250$GeV, with the MC simulation generator Jetset7.4 and Herwig5.9. The result is shown that this multi-particle final state is self-affine fractal, and exists a double-Hurst-exponent phenomenon. Their fractal indices and the effective fluctuation strength are also predicted.

   hep-phInt.J.Mod.Phys.A(2017)·0 citations
3. 03*

   The $n_f^2$ contributions to fermionic four-loop form factors

   Roman N. Lee🇷🇺 · Alexander V. Smirnov🇷🇺 · Vladimir A. Smirnov🇷🇺 · Matthias Steinhauser🇩🇪

   We compute the four-loop contributions to the photon quark and Higgs quark form factors involving two closed fermion loops. We present analytical results for all non-planar master integrals of the two non-planar integral families which enter our calculation.

   hep-phPRD(2017)·65 citations
4. 04*

   Herwig 7.1 Release Note

   Johannes Bellm🇬🇧 · Stefan Gieseke🇩🇪 · David Grellscheid🇬🇧 · Patrick Kirchgaeßer🇩🇪 · Frashër Loshaj🇩🇪 · Graeme Nail🇬🇧 · Andreas Papaefstathiou🇳🇱 · Simon Plätzer🇬🇧 · Radek Podskubka🇩🇪 · Michael Rauch🇩🇪 · Christian Reuschle🇺🇸 · Peter Richardson🇨🇭 and 4 other authors

   A new release of the Monte Carlo event generator Herwig (version 7.1) is now available. This version introduces a number of improvements, notably: multi-jet merging with the dipole shower at LO and NLO QCD; a new model for soft interactions and diffraction; improvements to mass effects and top decays in the dipole shower, as well as a new tune of the hadronisation parameters.

   hep-ph304 citations
5. 05*

   Standard Model - Axion - Seesaw - H portal inflation

   C. Tamarit🇬🇧

   Extending the Standard Model with a new complex singlet scalar, right-handed neutrinos and a vector-like quark allows to simultaneously tackle several problems in particle physics and cosmology within a constrained framework that can be falsified by future probes of the cosmic microwave background, as well as by upcoming axion experiments. This Standard Model - Axion - Seesaw - H portal inflation theory (SMASH) provides predictive inflation and $H$ boson stabilization, and can explain baryogenesis, light neutrino masses, dark matter and the strong CP problem. The model contains a unique new mass scale which coincides with the axion decay constant, and also sets the scale for perturbative lepton-number violation processes. Testable predictions include a minimum value of the tensor-to-scalar ratio of $r\gtrsim 0.004$, a running of the spectral index $\alpha \gtrsim -8\times 10^{-4}$, a change $\delta N_{\mathrm{eff}}\sim 0.03$ in the number of effective relativistic neutrinos, and an axion mass in the range $50\mu eV\le m_A\le 200\mu eV$.

   hep-phastro-ph.COhep-th0 citations
6. 06*

   Phenomenology of light- and strange-quark simultaneous production at high energies

   Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬 · Hayam Yassin🇪🇬 · Eman R. Abo Elyazeed (Ain Shams U., Cairo)🇪🇬

   This letter presents an extension of EPL116(2017)62001 to light- and strange-quark nonequilibrium chemical phase-space occupancy factors (${\gamma }_{q,s}$). The resulting damped trigonometric functionalities relating ${\gamma }_{q,s}$ to the nucleon-nucleon center-of-mass energies $(\sqrt{s_{NN}})$ looks very similar except different coefficients. The phenomenology of the resulting ${\gamma }_{q,s}(\sqrt{s_{NN}})$ describes a rapid decrease at $\sqrt{s_{NN}}\lesssim 7$GeV followed by a faster increase up to $\sim 20$GeV. Then, both ${\gamma }_{q,s}$ become nonsensitive to $\sqrt{s_{NN}}$. Although these differ from ${\gamma }_s(\sqrt{s_{NN}})$ obtained at ${\gamma }_q(\sqrt{s_{NN}})=1$, various particle ratios including ${\mathrm{K}}^{+}/{\pi }^{+}$, ${\mathrm{K}}^{-}/{\pi }^{-}$, $\mathrm{\Lambda }/{\pi }^{-}$, $\bar{\mathrm{\Lambda }}/{\pi }^{-}$, ${\mathrm{\Xi }}^{+}/{\pi }^{+}$, and $\mathrm{\Omega }/{\pi }^{-}$, can well be reproduced, as well. We conclude that ${\gamma }_{q,s}(\sqrt{s_{NN}})$ should be instead determined from fits of various particle yields and ratios but not merely from fits to the particle ratio ${\mathrm{K}}^{+}/{\pi }^{+}$.

   hep-phPhys.Part.Nucl.Lett.(2017)·4 citations
7. 07*

   Role of scalar mesons in the beam asymmetry of $p\bar{p}$ and $\Lambda \bar{\Lambda }$ photoproduction at JLab

   Thomas Gutsche🇩🇪 · Serguei Kuleshov🇨🇱 · Valery E. Lyubovitskij🇩🇪 · Igor T. Obukhovsky🇷🇺

   We suggest a description of the beam asymmetry in $p\bar{p}$ and $\Lambda \bar{\Lambda }$ photoproduction off the proton $\vec{\gamma }+p\to p\bar{p}+p$ and $\vec{\gamma }+p\to \Lambda \bar{\Lambda }+p$, takes into account the contribution of the scalar mesons $f_0(1370)$, $f_0(1500)$, and $f_0(1710)$. These scalars are considered as mixed states of a glueball and nonstrange and strange quarkonia in the framework based on the use of effective hadronic Lagrangians. Present results can be used to guide the possible search for this reaction by the GlueX Collaboration at JLab. Also, we did an estimate of contribution of heavier scalar meson states $f_0(2020)$, $f_0(2100)$, and $f_0(2200)$.

   hep-phPRD(2017)·3 citations
8. 08*

   Vector-like Leptons: Muon g-2 Anomaly, Lepton Flavor Violation, Higgs Decays, and Lepton Non-Universality

   Zijie Poh🇺🇸 · Stuart Raby🇺🇸

   In this paper, we consider the Standard Model (SM) with one family of vector-like (VL) leptons, which couple to all three families of the SM leptons. We study the constraints on this model coming from the heavy charged lepton mass bound, electroweak precision data, the muon anomalous magnetic moment, lepton flavor violation, Higgs decay constraints and a recently measured lepton non-universality observable, $R_{K^{\ast 0}}$. We find that the strongest constraints are coming from the muon $g-2,R_{\mu \mu }=\Gamma (h\to \mu \mu )/\Gamma (h\to \mu \mu {)}_{\text{SM}},R_{\gamma \gamma }$ and $\text{BR}(\mu \to e\gamma )$. Although VL leptons couple to all three families of the SM leptons, the ratio of electron-VL to muon-VL coupling is constrained to be $⟨{\lambda }_e/{\lambda }_{\mu }⟩\lesssim 10^{-4}$. We also find that our model cannot fit the observed value of $R_{K^{\ast 0}}$.

   hep-phPRD(2017)·75 citations
9. 09*

   Three Loop Massive Operator Matrix Elements and Asymptotic Wilson Coefficients with Two Different Masses

   J. Ablinger🇦🇹 · J. Blümlein🇩🇪 · A. De Freitas🇩🇪 · A. Hasselhuhn🇦🇹 · C. Schneider🇦🇹 · F. Wißbrock🇩🇪

   Starting at 3-loop order, the massive Wilson coefficients for deep-inelastic scattering and the massive operator matrix elements describing the variable flavor number scheme receive contributions of Feynman diagrams carrying quark lines with two different masses. In the case of the charm and bottom quarks, the usual decoupling of one heavy mass at a time no longer holds, since the ratio of the respective masses, $\eta =m_c^2/m_b^2\sim 1/10$, is not small enough. Therefore, the usual variable flavor number scheme (VFNS) has to be generalized. The renormalization procedure in the two--mass case is different from the single mass case derived in \cite{Bierenbaum:2009mv}. We present the moments $N=2,4$ and $6$ for all contributing operator matrix elements, expanding in the ratio $\eta$. We calculate the analytic results for general values of the Mellin variable $N$ in the flavor non-singlet case, as well as for transversity and the matrix element $A_{gq}^{(3)}$. We also calculate the two-mass scalar integrals of all topologies contributing to the gluonic operator matrix element $A_{gg}$. As it turns out, the expansion in $\eta$ is usually inapplicable for general values of $N$. We therefore derive the result for general values of the mass ratio. From the single pole terms we derive, now in a two-mass calculation, the corresponding contributions to the 3-loop anomalous dimensions. We introduce a new general class of iterated integrals and study their relations and present special values. The corresponding functions are implemented in computer-algebraic form.

   hep-phhep-exhep-thNPB(2017)·70 citations
10. 10*

    Neutrino Mass, Dark Matter and Baryon Asymmetry without Lepton Number Violation

    Shinya Kanemura (Osaka U.)🇯🇵 · Kodai Sakurai (U. of Toyama)🇯🇵 · Hiroaki Sugiyama (Toyama Prefectural U.)🇯🇵

    We propose a model to explain tiny masses of neutrinos with the lepton number conservation, where neither too heavy particles beyond the TeV-scale nor tiny coupling constants are required. Assignments of conserving lepton numbers to new fields result in an unbroken $Z_2$ symmetry that stabilizes the dark matter candidate (the lightest $Z_2$-odd particle). In this model, $Z_2$-odd particles play an important role to generate the mass of neutrinos. The scalar dark matter in our model can satisfy constraints on the dark matter abundance and those from direct searches. It is also shown that the strong first-order phase transition, which is required for the electroweak baryogenesis, can be realized in our model. In addition, the scalar potential can in principle contain CP-violating phases, which can also be utilized for the baryogenesis. Therefore, three problems in the standard model, namely absence of neutrino masses, the dark matter candidate, and the mechanism to generate baryon asymmetry of the Universe, may be simultaneously resolved at the TeV-scale. Phenomenology of this model is also discussed briefly.

    hep-phPRD(2017)·7 citations
11. 11*

    Magnetic monopole mass bounds from heavy ion collisions and neutron stars

    Oliver Gould🇬🇧 · Arttu Rajantie🇬🇧

    Magnetic monopoles, if they exist, would be produced amply in strong magnetic fields and high temperatures via the thermal Schwinger process. Such circumstances arise in heavy ion collisions and in neutron stars, both of which imply lower bounds on the mass of possible magnetic monopoles. In showing this, we construct the cross section for pair production of magnetic monopoles in heavy ion collisions, which indicates that they are particularly promising for experimental searches such as MoEDAL.

    hep-phastro-ph.HEhep-thnucl-thPRL(2017)·84 citations
12. 12*

    Analysis of the ${\Lambda }_c(2860)$, ${\Lambda }_c(2880)$, ${\Xi }_c(3055)$ and ${\Xi }_c(3080)$ as D-wave baryon states with QCD sum rules

    Zhi-Gang Wang🇨🇳

    In this article, we tentatively assign the ${\Lambda }_c(2860)$, ${\Lambda }_c(2880)$, ${\Xi }_c(3055)$ and ${\Xi }_c(3080)$ to be the D-wave baryon states with the spin-parity $J^P={\frac{3}{2}}^{+}$, ${\frac{5}{2}}^{+}$, ${\frac{3}{2}}^{+}$ and ${\frac{5}{2}}^{+}$, respectively, and study their masses and pole residues with the QCD sum rules in a systematic way by constructing three-types interpolating currents with the quantum numbers $(L_{\rho },L_{\lambda })=(0,2)$, $(2,0)$ and $(1,1)$, respectively. The present predictions favor assigning the ${\Lambda }_c(2860)$, ${\Lambda }_c(2880)$, ${\Xi }_c(3055)$ and ${\Xi }_c(3080)$ to be the D-wave baryon states with the quantum numbers $(L_{\rho },L_{\lambda })=(0,2)$ and $J^P={\frac{3}{2}}^{+}$, ${\frac{5}{2}}^{+}$, ${\frac{3}{2}}^{+}$ and ${\frac{5}{2}}^{+}$, respectively. While the predictions for the masses of the $(L_{\rho },L_{\lambda })=(2,0)$ and $(1,1)$ D-wave ${\Lambda }_c$ and ${\Xi }_c$ states can be confronted to the experimental data in the future.

    hep-phNPB(2018)·37 citations
13. 13*

    The electromagnetic chirp of a compact binary black hole: a phase template for the gravitational wave inspiral

    Zoltán Haiman (Columbia University and NYU)🇺🇸

    The gravitational waves (GWs) from a binary black hole (BBH) with masses between 10^4 and 10^7 Msun can be detected with the Laser Interferometer Space Antenna (LISA) once their orbital frequency exceeds 10^-4 - 10^-5 Hz. The binary separation at this stage is approximately a=100 R_g (gravitational radius), and the orbital speed is of order v/c=0.1. We argue that at this stage, the binary will be producing bright electromagnetic (EM) radiation via gas bound to the individual BHs. Both BHs will have their own photospheres in X-ray and possibly also in optical bands. Relativistic Doppler modulations and lensing effects will inevitably imprint periodic variability in the EM light-curve, tracking the phase of the orbital motion, and serving as a template for the GW inspiral waveform. Advanced localization of the source by LISA weeks to months prior to merger will enable a measurement of this EM chirp by wide-field X-ray or optical instruments. A comparison of the phases of the GW and EM chirp signals will help break degeneracies between system parameters, and probe a fractional difference difference Delta v in the propagation speed of photons and gravitons as low as Delta v/c = O(10^-17).

    ↳ astro-ph.HEgr-qchep-phPRD(2017)·79 citations
14. 14*

    Sgoldstino-less inflation and low energy SUSY breaking

    Riccardo Argurio🇧🇪 · Dries Coone🇧🇪 · Lucien Heurtier🇧🇪 · Alberto Mariotti🇧🇪

    We assess the range of validity of sgoldstino-less inflation in a scenario of low energy supersymmetry breaking. We first analyze the consistency conditions that an effective theory of the inflaton and goldstino superfields should satisfy in order to be faithfully described by a sgoldstino-less model. Enlarging the scope of previous studies, we investigate the case where the effective field theory cut-off, and hence also the sgoldstino mass, are inflaton-dependent. We then introduce a UV complete model where one can realize successfully sgoldstino-less inflation and gauge mediation of supersymmetry breaking, combining the alpha-attractor mechanism and a weakly coupled model of spontaneous breaking of supersymmetry. In this class of models we find that, given current limits on superpartner masses, the gravitino mass has a lower bound of the order of the MeV, i.e. we cannot reach very low supersymmetry breaking scales. On the plus side, we recognize that in this framework, one can derive the complete superpartner spectrum as well as compute inflation observables, the reheating temperature, and address the gravitino overabundance problem. We then show that further constraints come from collider results and inflation observables. Their non trivial interplay seems a staple feature of phenomenological studies of supersymmetric inflationary models.

    ↳ hep-thastro-ph.COhep-phJCAP(2017)·19 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.