Wed·Aug 23, 2017Wednesday·August 23, 2017

1. 01*

   LSP baryogenesis and neutron-antineutron oscillations from R-parity violation

   Lorenzo Calibbi🇨🇳 · Eung Jin Chun🇰🇷 · Chang Sub Shin🇰🇷

   R-parity and baryon number violating operators can be allowed in the Supersymmetric Standard Model and thus lead to interesting baryon number violating processes such as neutron-antineutron oscillations and baryogenesis of the Universe via the decay of the lightest supersymmetric particle (LSP). Adopting the LSP baryogenesis mechanism realized by the late decay of the axino, we identify a single coupling lambda''_313 as a common origin for the matter-antimatter asymmetry of the Universe as well as potentially observable neutron-antineutron oscillation rates. From this, rather strong constraints on the supersymmetry breaking masses and the axion decay constant are obtained. The favoured parameter space of lambda''_313 ~ 0.1 and sub-TeV masses for the relevant sparticles is readily accessible by the current and future LHC searches.

   hep-phJHEP(2017)·10 citations
2. 02*

   Very low scale Coleman-Weinberg inflation with non-minimal coupling

   Kunio Kaneta🇰🇷 · Osamu Seto🇯🇵 · Ryo Takahashi🇯🇵

   We study viable small-field Coleman-Weinberg (CW) inflation models with the help of non-minimal coupling to gravity. The simplest small-field CW inflation model (with a low-scale potential minimum) is incompatible with the cosmological constraint on the scalar spectral index. However, there are possibilities to make the model realistic. First, we revisit the CW inflation model supplemented with a linear potential term. We next consider the CW inflation model with a logarithmic non-minimal coupling and illustrate that the model can open a new viable parameter space that includes the model with a linear potential term. We also show parameter spaces where the Hubble scale during the inflation can be as small as $10^{-4}$ GeV, $1$ GeV, $10^4$ GeV, and $10^8$ GeV for the number of $e$-folds of $40,45,50$, and $55$, respectively, with other cosmological constraints being satisfied.

   hep-phastro-ph.COhep-thPRD(2018)·15 citations
3. 03*

   On possibility of time reversal symmetry violation in neutrino elastic scattering on polarized electron target

   W. Sobków (1)🇵🇱 · A. Błaut (1) ((1) Institute of Theoretical Physics, University of Wrocław)🇵🇱

   In this paper, we indicate a possibility of utilizing the elastic scattering of the Dirac low energy ($\sim 1$ MeV) electron neutrinos (${\nu }_e$'s) on the polarized electron target (PET) in testing the time reversal symmetry violation (TRSV). We consider a scenario in which the incoming ${\nu }_e$ beam is the superposition of left chiral (LC) and right chiral (RC) states. LC ${\nu }_e$'s interact mainly by the standard $V-A$, while RC ones are only detected by the exotic $V+A$ and $S_R,P_R,T_R$ interactions. One assumes that the spin polarization vector of the initial ${\nu }_e$'s is turned aside from the ${\nu }_e$ momentum, and due to this the non-vanishing transversal component of the ${\nu }_e$ spin polarization appears. We compute the differential cross section as a function of the recoil electron azimuthal angle and scattered electron energy, and show how the interference terms between standard $V-A$ and exotic $S_R,P_R,T_R$ couplings depend on the various angular correlations among the transversal ${\nu }_e$ spin polarization, the polarization of the electron target, the incoming neutrino momentum and the outgoing electron momentum in the limit of relativistic ${\nu }_e$. We illustrate how the maximal value of recoil electrons azimuthal asymmetry and the asymmetry axis location of outgoing electrons depend on the azimuthal angle of the transversal component of the ${\nu }_e$ spin polarization, both for the time reversal symmetry conservation (TRSC) and TRSV. Next, we display that the electron energy spectrum and polar angle distribution of the recoil electrons are also sensitive to the interference terms between $V-A$ and $S_R,P_R,T_R$ couplings, proportional to the T-even and T-odd angular correlations. Our model-independent analysis is carried out for the flavor ${\nu }_e$'s.

   hep-phEPJC(2018)·4 citations
4. 04*

   Constraints on parameter space of BLMSSM from particle mass

   Hui Li🇨🇳 · Jian-Bin Chen🇨🇳 · Li-Li Xing🇨🇳

   To explaine the matter-antimatter asymmetry, a supersymmetric extention of the standard model is proposed where baryon and lepton numbers are local gauged(BLMSSM), and exotic superfields are introduced when gauge group is enlarged to $SU(3{)}_C\otimes SU(2{)}_L\otimes U(1{)}_Y\otimes U(1{)}_B\otimes U(1{)}_L$. As signals of new physics have not been observed on Large Hadron Collider, the parameter space relevant to the masses of new particles is stringently constrainted. By diagonalizing the mass squared matrices for neutral scalar sectors and the mass matrices for exotic quarks, we plot the masses of new particles varying with different parameters with some assumptions, so the constraints on model parameter is obtained with different lower limit on particle mass.

   hep-phMod.Phys.Lett.A(2018)·1 citation
5. 05*

   Non-perturbative reheating and Nnaturalness

   Edward Hardy🇬🇧

   We study models in which reheating happens only through non-perturbative processes. The energy transferred can be exponentially suppressed unless the inflaton is coupled to a particle with a parametrically small mass. Additionally, in some models a light scalar with a negative mass squared parameter leads to much more efficient reheating than one with a positive mass squared of the same magnitude. If a theory contains many sectors similar to the Standard Model coupled to the inflaton via their Higgses, such dynamics can realise the Nnaturalness solution to the hierarchy problem. A sector containing a light Higgs with a non-zero vacuum expectation value is dominantly reheated and there is little energy transferred to the other sectors, consistent with cosmological constraints. The inflaton must decouple from other particles and have a flat potential at large field values, in which case the visible sector UV cutoff can be raised to 10 TeV in a simple model.

   hep-phJHEP(2017)·1 citation
6. 06*

   Dipole factorization for DIS at NLO: Combining the $q\bar{q}$ and $q\bar{q}g$ contributions

   Guillaume Beuf🇮🇹

   The NLO corrections to the DIS structure functions $F_2$ and $F_L$ (or equivalently the photon-target cross sections ${\sigma }_T^{{\gamma }^{\ast }}$ and ${\sigma }_L^{{\gamma }^{\ast }}$) at low $x_{Bj}$ are obtained, as a generalization of the dipole factorization formula. For the first time, the contributions of both the $q\bar{q}$ and the $q\bar{q}g$ Fock states in the photon are directly calculated, using earlier results for the $q\bar{q}$ light-front wave-functions at one loop inside a dressed virtual photon. Both the $q\bar{q}$ and the $q\bar{q}g$ contributions have UV divergences, which are shown to cancel each other, using conventional dimensional regularization as UV regulator. Finally, the resummation of high-energy logarithms on top of the NLO results for ${\sigma }_T^{{\gamma }^{\ast }}$ and ${\sigma }_L^{{\gamma }^{\ast }}$ is discussed.

   hep-phPRD(2017)·123 citations
7. 07*

   Exploring supersymmetry with machine learning

   Jie Ren🇨🇳 · Lei Wu🇨🇳 · Jin Min Yang🇨🇳 · Jun Zhao🇨🇳

   Investigation of well-motivated parameter space in the theories of Beyond the Standard Model (BSM) plays an important role in new physics discoveries. However, a large-scale exploration of models with multi-parameter or equivalent solutions with a finite separation, such as supersymmetric models, is typically a time-consuming and challenging task. In this paper, we propose a self-exploration method, named Machine Learning Scan (MLS), to achieve an efficient test of models. As a proof-of-concept, we apply MLS to investigate the subspace of MSSM and CMSSM and find that such a method can reduce the computational cost and may be helpful for accelerating the exploration of supersymmetry.

   hep-phNPB(2019)·65 citations
8. 08*

   Recent developments on parton-to-photon fragmentation functions

   Tom Kaufmann🇩🇪 · Asmita Mukherjee🇮🇳 · Werner Vogelsang🇩🇪

   We report on some recent developments concerning parton-to-photon fragmentation functions. We briefly summarize the main theoretical concepts on which the currently available extractions of these fragmentation functions rely: evolution and the vector meson dominance model. We present comparisons of the available sets. We argue that the single-inclusive photon production process $pp\to \gamma X$ possesses only little sensitivity to the fragmentation contribution. Instead, the semi-inclusive process $pp\to (\text{jet}\gamma )X$, for which the photon is observed inside a fully reconstructed jet and is part of the jet, is shown to offer much potential for providing valuable new information.

   hep-phhep-exCERN Proc.(2018)·7 citations
9. 09*

   Thermodynamic and transport properties in Au + Au collisions at RHIC energies from the clustering of color strings

   Pragati Sahoo🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Sudipan De🇮🇳 · Raghunath Sahoo🇮🇳 · Rolf P. Scharenberg🇺🇸 · Brijesh K. Srivastava🇺🇸

   In this work, we have extracted the initial tempearture from the transverse momentum spectra of charged particles in $Au+Au$ collisions using STAR data at RHIC energies from $\sqrt{s_{NN}}$ = 7.7 to 200 GeV. The initial energy density ($\epsilon$), shear viscosity to entropy density ratio ($\eta /s$), trace anomaly ($\Delta$), the squared speed of sound ($C_s^2$), entropy density, and bulk viscosity to entropy density ratio ($\zeta /s$) are obtained and compared with the lattice QCD calculations for (2+1) flavor. The initial temperatures obtained are compared with various hadronization and chemical freeze-out temperatures. The analysis of the data shows that the deconfinement to confinement transition possibly takes place between $\sqrt{s_{NN}}$ = 11.5 and 19.6 GeV.

   hep-phhep-exhep-latnucl-ex+1Mod.Phys.Lett.A(2019)·30 citations
10. 10*

    Analytic Boosted Boson Discrimination at the Large Hadron Collider

    Andrew J. Larkoski🇺🇸 · Ian Moult🇺🇸 · Duff Neill🇺🇸

    Jet substructure is playing a central role at the Large Hadron Collider (LHC) probing the Standard Model in extreme regions of phase space and providing innovative ways to search for new physics. Analytic calculations of experimentally successful observables are a primary catalyst driving developments in jet substructure, allowing for a deeper understanding of observables and for the exploitation of increasingly subtle features of jets. In this paper we present a field theoretic framework enabling systematically improvable calculations of groomed multi-prong substructure observables, which builds on recent developments in multi-scale effective theories. We use this framework to compute for the first time the full spectrum for groomed tagging observables at the LHC, carefully treating both perturbative and non-perturbative contributions in all regions. Our analysis enables a precision understanding which we hope will improve the reach and sophistication of jet substructure techniques at the LHC.

    hep-phnucl-th40 citations
11. 11*

    Self-interacting Spin-2 Dark Matter

    Xiaoyong Chu🇦🇹 · Camilo Garcia-Cely🇧🇪

    Recent developments in bigravity allow one to construct consistent theories of interacting spin-2 particles that are free of ghosts. In this framework, we propose an elementary spin-2 dark matter candidate with a mass well below the TeV scale. We show that, in a certain regime where the interactions induced by the spin-2 fields do not lead to large departures from the predictions of general relativity, such a light dark matter particle typically self-interacts and undergoes self-annihilations via 3-to-2 processes. We discuss its production mechanisms and also identify the regions of the parameter space where self-interactions can alleviate the discrepancies at small scales between the predictions of the collisionless dark matter paradigm and cosmological N-body simulations.

    hep-phgr-qcPRD(2017)·44 citations
12. 12*

    Nonperturbative quantization à la Heisenberg and thermodynamics of monopole configurations

    Vladimir Dzhunushaliev · Vladimir Folomeev · Hernando Quevedo

    For field theories in which no small parameter is available, we propose a definition of nonperturbative quantum states in terms of the complete set of Green functions, based upon the utilization of Heisenberg's quantization procedure. We apply this method to obtain the energy spectra of a quantum monopole and of a flux tube. The partition function and thermodynamic quantities for one quantum monopole are evaluated numerically. A dilute gas of noninteracting quantum monopoles is considered, for which the partition function and thermodynamic quantities are evaluated as well. All the obtained statistical and thermodynamic functions contain quantum corrections associated with the internal structure of the quantum monopole.

    ↳ hep-thhep-ph1 citation
13. 13*

    Scale-Dependent Galaxy Bias from Massive Particles with Spin during Inflation

    Azadeh Moradinezhad Dizgah🇺🇸 · Cora Dvorkin🇺🇸

    The presence of additional particles during inflation leads to non-Gaussianity in late-time correlators of primordial curvature perturbations. The shape and amplitude of this signal depend on the mass and spin of the extra particles. Constraints on this distinct form of primordial non-Gaussianity, therefore, provide a wealth of information on the particle content during inflation. We investigate the potential of upcoming galaxy surveys in constraining such a signature through its impact on the observed galaxy power spectrum. Primordial non-Gaussianity of various shapes induces a scale-dependent bias on tracers of large-scale structure, such as galaxies. Using this signature we obtain constraints on massive particles during inflation, which can have non-zero spins. In particular, we show that the prospects for constraining particles with spins 0 and 1 are promising, while constraining particles with spin 2 from power spectrum alone seems challenging. We show that the multi-tracer technique can significantly improve the constraints from the power spectrum by at least an order of magnitude. Furthermore, we analyze the effect of non-linearities due to gravitational evolution on the forecasted constraints on the masses of the extra particles and the amplitudes of the imprinted non-Gaussian signal. We find that gravitational evolution affects the constraints by less than a factor of 2.

    ↳ astro-ph.COhep-phhep-thJCAP(2018)·67 citations
14. 14*

    A statistical analysis of two-dimensional patterns and its application to astrometry

    Petr Zavada🇨🇿 · Karel Píška🇨🇿

    Here we develop a general statistical procedure for the analysis of finite two-dimensional (2D) patterns inspired by the analysis of heavy-ion data. The method is used in the study of publicly available data obtained by the Gaia-ESA mission. We prove that the procedure can be sensitive to the limits of accuracy of measurement, and can also clearly identify the real physical effects on the large background of random distributions. As an example, the method confirms the presence of binary and ternary star systems in the studied data. At the same time, the possibility of the statistical detection of the gravitational microlensing effect is discussed.

    ↳ astro-ph.IMhep-phJ.Phys.Conf.Ser.(2017)·2 citations
15. 15*

    Analyzing {\gamma}-rays of the Galactic Center with Deep Learning

    Sascha Caron🇳🇱 · Germán A. Gómez-Vargas🇨🇱 · Luc Hendriks🇳🇱 · Roberto Ruiz de Austri🇪🇸

    We present a new method to interpret the $\gamma$-ray data of our inner Galaxy as measured by the Fermi Large Area Telescope (Fermi LAT). We train and test convolutional neural networks with simulated Fermi-LAT images based on models tuned to real data. We use this method to investigate the origin of an excess emission of GeV $\gamma$-rays seen in previous studies. Interpretations of this excess include $\gamma$ rays created by the annihilation of dark matter particles and $\gamma$ rays originating from a collection of unresolved point sources, such as millisecond pulsars. Our new method allows precise measurements of the contribution and properties of an unresolved population of $\gamma$-ray point sources in the interstellar diffuse emission model.

    ↳ astro-ph.HEhep-phJCAP(2018)·44 citations
16. 16*

    Flat Monodromies and a Moduli Space Size Conjecture

    Arthur Hebecker🇩🇪 · Philipp Henkenjohann🇩🇪 · Lukas T. Witkowski🇫🇷

    We investigate how super-Planckian axions can arise when type IIB 3-form flux is used to restrict a two-axion field space to a one-dimensional winding trajectory. If one does not attempt to address notoriously complicated issues like Kahler moduli stabilization, SUSY-breaking and inflation, this can be done very explicitly. We show that the presence of flux generates flat monodromies in the moduli space which we therefore call 'Monodromic Moduli Space'. While we do indeed find long axionic trajectories, these are non-geodesic. Moreover, the length of geodesics remains highly constrained, in spite of the (finite) monodromy group introduced by the flux. We attempt to formulate this in terms of a 'Moduli Space Size Conjecture'. Interesting mathematical structures arise in that the relevant spaces turn out to be fundamental domains of congruence subgroups of the modular group. In addition, new perspectives on inflation in string theory emerge.

    ↳ hep-thhep-phJHEP(2017)·79 citations
17. 17*

    Black Holes and High Energy Physics: From Astrophysics to Large Extra Dimensions

    Michael Florian Wondrak🇩🇪 · Marcus Bleicher🇩🇪 · Piero Nicolini🇩🇪

    Up to now, Einstein's general theory of relativity has passed all experimental tests. But yet we know that it is not a fundamental theory and that it is incompatible with quantum theory. While several extended and improved gravitational theories on classical and quantum level are nowadays available, it is a great challenge to find experimental setups to check their signatures. We discuss recent developments in direct observation of black holes comprising gravitational waves from black hole mergers, radio interferometry images of black hole shadows, and Hawking radiation of black holes in particle accelerators. These investigations cover the full black hole mass range from microscopic to stellar and supermassive black holes. We comment on the associated strong-field tests of Einstein's general theory of relativity and implications for quantum gravity. Special emphasis lies upon the physics of large extra dimensions and black hole evaporation, the existence of a minimal black hole mass, and the cross sections of higher-dimensional black holes. We complete this short review with the latest experimental constraints at the Large Hadron Collider.

    ↳ gr-qchep-phhep-th4 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.