Tue·Dec 19, 2017Tuesday·December 19, 2017

1. 01*

   Supersymmetric Theory and Models

   Howard E. Haber🇺🇸 · Laurel Stephenson Haskins🇺🇸

   In these introductory lectures, we review the theoretical tools used in constructing supersymmetric field theories and their application to physical models. We first introduce the technology of two-component spinors, which is convenient for describing spin-$1/2$ fermions. After motivating why a theory of nature may be supersymmetric at the TeV energy scale, we show how supersymmetry (SUSY) arises as an extension of the Poincaré algebra of spacetime symmetries. We then obtain the representations of the SUSY algebra and discuss its simplest realization in the Wess-Zumino model. In order to have a systematic approach for obtaining supersymmetric Lagrangians, we introduce the formalism of superspace and superfields and recover the Wess-Zumino Lagrangian. These methods are then extended to encompass supersymmetric abelian and non-abelian gauge theories coupled to supermatter. Since supersymmetry is not an exact symmetry of nature, it must ultimately be broken. We discuss several mechanisms of SUSY-breaking (both spontaneous and explicit) and briefly survey various proposals for realizing SUSY-breaking in nature. Finally, we construct the the Minimal Supersymmetric extension of the Standard Model (MSSM), and consider the implications for the future of SUSY in particle physics.

   hep-phhep-thin Proceedings of TASI 2016, Rouven Essig…·36 citations
2. 02*

   Calculations with off-shell matrix elements, TMD parton densities and TMD parton showers

   Marcin Bury🇵🇱 · Andreas van Hameren🇵🇱 · Hannes Jung🇩🇪 · Krzysztof Kutak🇵🇱 · Sebastian Sapeta🇵🇱 · Mirko Serino🇵🇱

   A new calculation using off-shell matrix elements with TMD parton densities supplemented with a newly developed initial state TMD parton shower is described. The calculation is based on the KaTie package for an automated calculation of the partonic process in high-energy factorization, making use of TMD parton densities implemented in TMDlib. The partonic events are stored in an LHE file, similar to the conventional LHE files, but now containing the transverse momenta of the initial partons. The LHE files are read in by the CASCADE package for the full TMD parton shower, final state shower and hadronization from PYTHIA where events in HEPMC format are produced. We have determined a full set of TMD parton densities and developed an initial state TMD parton shower, including all flavors following the TMD distribution. As an example of application we have calculated the azimuthal de-correlation of high pt dijets as measured at the LHC and found very good agreement with the measurement when including initial state TMD parton showers together with conventional final state parton showers and hadronization.

   hep-phEPJC(2018)·43 citations
3. 03*

   Synergy and complementarity between neutrino physics and low-energy intensity frontiers

   Ana M. Teixeira🇫🇷

   Massive neutrinos and leptonic mixings have provided the first evidence of flavour violation in the lepton sector, opening a unique gateway to many new phenomena. Among the latter, one finds processes violating lepton number, charged lepton flavours, or even the universality of lepton flavours. These very rare transitions can be studied in high-intensity facilities, and if observed, constitute a clear sign of New Physics. After a brief review of the experimental status of dedicated searches, we comment on the prospects of several well-motivated models of neutrino mass generation to several of the above mentioned observables, also discussing how the interplay of high-intensity observables and neutrino data can shed light on the underlying New Physics model.

   hep-phPoS(2017)·0 citations
4. 04*

   Charmonium interaction in nuclear matter at FAIR

   Partha Pratim Bhaduri🇮🇳 · Michael Deveaux🇩🇪 · Alberica Toia🇩🇪

   We have studied the dissociation of $J/\psi$-mesons in low energy proton-nucleus ($p+A$) collisions in the energy range of the future SIS100 accelerator at Facility for Anti-proton and Ion Research (FAIR). According to the results of our calculations, various scenarios of $J/\psi$ absorption in nuclear matter show very distinct suppression patterns in the kinematic regime to be probed at FAIR. This suggests that the SIS100 energies are particularly suited to shed light on the issue of interaction of $J/\psi$ resonance in nuclear medium.

   hep-phJ.Phys.G(2018)·4 citations
5. 05*

   Chiral Magnetic Effect in the Dirac-Heisenberg-Wigner formalism

   Dániel Berényi🇭🇺 · Péter Lévai🇭🇺

   The emergence of the Chiral Magnetic Effect (CME) and the related anomalous current is investigated using the real time Dirac-Heisenberg-Wigner formalism. This method is widely used for describing strong field physics and QED vacuum tunneling phenomena as well as pair-production in heavy-ion collisions. We extend earlier investigations of the CME in constant fluxtube configuration by considering time dependent fields. In our model we can follow the formation of axial charge separation, formation of axial current and then the emergence of the anomalous electric current. Qualitative results are shown for special field configurations that help interpret the predictions of CME related effects in heavy-ion collisions in the RHIC Beam Energy Scan program.

   hep-phPoS(2017)·0 citations
6. 06*

   $J/\psi$ regeneration in a hadron gas: an update

   L. M. Abreu🇧🇷 · K. P. Khemchandani🇧🇷 · A. Martínez Torres🇧🇷 · F. S. Navarra🇧🇷 · M. Nielsen🇧🇷

   In heavy ion collisions after the quark-gluon plasma there is a hadronic gas phase. Using effective Lagrangians we study the interactions of charmed mesons which lead to $J/\psi$ production and absorption in this gas. We update and extend previous calculations introducing strange meson interactions and also including the interactions mediated by the recently measured exotic charmonium resonances $Z(3900)$ and $Z(4025)$. These resonances open new reaction channels for the $J/\psi$, which could potentially lead to changes in its multiplicity. We compute the $J/\psi$ production cross section in processes such as $D_{(s)}^{(\ast )}+{\bar{D}}^{(\ast )}\to J/\psi +(\pi ,\rho ,K,K^{\ast })$ and also the $J/\psi$ absorption cross section in the corresponding inverse processes. Using the obtained cross sections as input to solve the rate equation, we conclude that the interactions in the hadron gas phase do not significantly affect the $J/\Psi$ abundance. In other words, there is neither a charmonium suppression nor charmonium regeneration from light mesons in the hadronic phase.

   hep-phPRC(2018)·28 citations
7. 07*

   SUSY-like relation in evolution of gluon and quark jet multiplicities

   Bernd A. Kniehl🇩🇪 · Anatoly V. Kotikov🇷🇺

   We show the new relationship [1] between the anomalous dimensions, resummed through next-to-next-to-leading-logarithmic order, in the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations for the first Mellin moments D{q,g}(\mu2) of the quark and gluon fragmentation functions, which correspond to the average hadron multiplicities in jets initiated by quarks and gluons, respectively. This relationship, which is independent of the number of quark flavors, strongly improves previous treatments by allowing for an exact solution of the evolution equations. So far, such relationships have only been known from supersymmetric QCD.

   hep-phPhys.Part.Nucl.(2018)·3 citations
8. 08*

   Bjorken sum rule in QCD with analytic coupling

   C. Ayala🇨🇱 · G. Cvetic🇨🇱 · A.V. Kotikov🇷🇺 · B.G. Shaikhatdenov🇷🇺

   We present details of study of the Bjorken polarized sum rule carried out recently in [1] within the range of energies where the data were collected by JLAB collaboration, 0.05 GeV2 < Q2 < 3 GeV2. Three approaches to QCD with analytic (holomorphic) coupling are considered: Analytic Perturbation Theory (APT), Two-delta analytic QCD, and Three-delta lattice-motivated analytic QCD in the three-loop and four-loop MiniMOM schemes. The new frameworks with respective couplings give results which agree well with the experimental data for 0.5 GeV2 < Q2 < 3GeV2 already when only one higher-twist term is taken into account.

   hep-phJ.Phys.Conf.Ser.(2017)·12 citations
9. 09*

   Revised and Improved Value of the QED Tenth-Order Electron Anomalous Magnetic Moment

   Tatsumi Aoyama🇯🇵 · Toichiro Kinoshita🇺🇸 · Makiko Nio🇯🇵

   In order to improve the theoretical prediction of the electron anomalous magnetic moment $a_e$ we have carried out a new numerical evaluation of the 389 integrals of Set V, which represent 6,354 Feynman vertex diagrams without lepton loops. During this work, we found that one of the integrals, called $X024$, was given a wrong value in the previous calculation due to an incorrect assignment of integration variables. The correction of this error causes a shift of $-1.25$ to the Set~V contribution, and hence to the tenth-order universal (i.e., mass-independent) term $A_1^{(10)}$. The previous evaluation of all other 388 integrals is free from errors and consistent with the new evaluation. Combining the new and the old (excluding $X024$) calculations statistically, we obtain $7.606(192)(\alpha /\pi {)}^5$ as the best estimate of the Set V contribution. Including the contribution of the diagrams with fermion loops, the improved tenth-order universal term becomes $A_1^{(10)}=6.678(192)$. Adding hadronic and electroweak contributions leads to the theoretical prediction $a_e(\text{theory})=1159652182.032(720)\times 10^{-12}$. From this and the best measurement of $a_e$, we obtain the inverse fine-structure constant ${\alpha }^{-1}(a_e)=137.0359991491(331)$. The theoretical prediction of the muon anomalous magnetic moment is also affected by the update of QED contribution and the new value of $\alpha$, but the shift is much smaller than the theoretical uncertainty.

   hep-phPRD(2018)·301 citations
10. 10*

    Direct CP violation in $K^0\to \pi \pi$: Standard Model Status

    Hector Gisbert🇪🇸 · Antonio Pich🇪🇸

    In 1988 the NA31 experiment presented the first evidence of direct CP violation in the $K^0\to \pi \pi$ decay amplitudes. A clear signal with a $7.2\sigma$ statistical significance was later established with the full data samples from the NA31, E731, NA48 and KTeV experiments, confirming that CP violation is associated with a $\Delta S=1$ quark transition, as predicted by the Standard Model. However, the theoretical prediction for the measured ratio ${\epsilon }^{\prime }/\epsilon$ has been a subject of strong controversy along the years. Although the underlying physics was already clarified in 2001, the recent release of improved lattice data has revived again the theoretical debate. We review the current status, discussing in detail the different ingredients that enter into the calculation of this observable and the reasons why seemingly contradictory predictions were obtained in the past by several groups. An update of the Standard Model prediction is presented and the prospects for future improvements are analysed. Taking into account all known short-distance and long-distance contributions, one obtains $\text{mbox}Re\left({\epsilon }^{\prime }/\epsilon \right)=(15\pm 7)\cdot 10^{-4}$, in good agreement with the experimental measurement.

    hep-phhep-exhep-latRept.Prog.Phys.(2018)·69 citations
11. 11*

    Relativistic corrections to exclusive ${\chi }_{cJ}+\gamma$ production from $e^{+}{e}^{-}$ annihilation

    Nora Brambilla🇩🇪 · Wen Chen🇨🇳 · Yu Jia🇨🇳 · Vladyslav Shtabovenko🇩🇪 · Antonio Vairo🇩🇪

    We calculate in the non-relativistic QCD (NRQCD) factorization framework all leading relativistic corrections to the exclusive production of ${\chi }_{cJ}+\gamma$ in $e^{+}{e}^{-}$ annihilation. In particular, we compute for the first time contributions induced by octet operators with a chromoelectric field. The matching coefficients multiplying production long distance matrix elements (LDMEs) are determined through perturbative matching between QCD and NRQCD at the amplitude level. Technical challenges encountered in the non-relativistic expansion of the QCD amplitudes are discussed in detail. The main source of uncertainty comes from the not so well known LDMEs. Accounting for it, we provide the following estimates for the production cross sections at $\sqrt{s}=10.6\text{ GeV}$: $\sigma (e^{+}{e}^{-}\to {\chi }_{c0}+\gamma )=(1.3\pm 0.4)\text{ fb}$, $\sigma (e^{+}{e}^{-}\to {\chi }_{c1}+\gamma )=(15.4\pm 6.7)\text{ fb}$, and $\sigma (e^{+}{e}^{-}\to {\chi }_{c2}+\gamma )=(4.7\pm 2.6)\text{ fb}$.

    hep-phhep-exnucl-thPRD(2018)·24 citations
12. 12*

    B meson decay anomaly with a non-universal U(1)' extension

    R. Martinez🇨🇴 · F. Ochoa🇨🇴 · J.M. Quimbayo🇨🇴

    We propose an extension of the standard model with an extra U(1)' abelian symmetry, three Higgs doublets and one Higgs singlet, where the new U(1)' charges are flavour non-universal. As a result, the model introduces an enlarger particle spectrum in the TeV scale with large new physics possibilities. The model reproduces the mixing angles and mass structures of the quarks, charged and neutral leptons. We found that the observed anomaly of the $B^{+}\to K^{+}\ell \ell$ decay can be explained due to the existence of couplings with new extra fermions at the TeV scale.

    hep-phPRD(2018)·5 citations
13. 13*

    Phenomenology of Vector-like Fermions in Physics Beyond the Standard Model

    Victor Peralta🇧🇷

    The Standard model of particle physics provides a successful theory to understand the experimental results of the electroweak and strong interactions. However, it does not have a satisfactory explanation for the hierarchy problem. Many extensions of the Standard Model that solve the hierarchy problem result in new particles. We will study the phenomenology of vector-like fermions resulting in theories where the Higgs boson is typically a pseudo-Nambu-Goldstone boson. In these theories we study the case where a heavy fermion will be heavier than a heavy gluon, and then the channel of a heavy fermion decaying into a color octet is considered. We study this phenomenology at high energy colliders, both the LHC as well as future machines.

    hep-ph5 citations
14. 14*

    Investigation of confinement-deconfinement transition via probability distributions

    Kouji Kashiwa🇯🇵 · Akira Ohnishi🇯🇵

    We investigate the confinement-deconfinement transition at finite temperature in terms of the probability distribution of Polyakov-loop complex-phase via the Jensen-Shannon divergence. The Jensen-Shannon divergence quantifies the difference of two probability distributions, namely the target and reference probability distributions. We adopt the complex-phase distributions of the spatially averaged Polyakov loop at $\mu /T=0$ and $\mu /T=i\pi /3$ as the target and reference distributions, respectively. It is shown that the Jensen-Shannon divergence has the inflection point when the target system approaches the Roberge-Weiss endpoint temperature even in the finite-volume system. This means that we can detect the confinement-deconfinement transition from the structural change of probability distributions when we suitably set the reference probability distribution. It is also shown that we can pick up the information of the confinement-deconfinement transition from the quark number density by using the Fourier decomposition; Fourier coefficients have a long tail at around the transition temperature and show a divergent series in calculating the normalized kurtosis.

    hep-phhep-lathep-th9 citations
15. 15*

    Two Gluon Emission from MHV: Two Particle Correlations and the Deviation from Poisson

    A. N. Rasoanaivo🇿🇦 · W. A. Horowitz🇿🇦

    We derive the momentum distribution for two soft and collinear gluons emitted from an off-shell quark, modeled by a $q\gamma \to qgg$ scattering process and computed using the maximal helicity violating (MHV) technique. We find the explicit non-Abelian corrections to the independent emission Poisson distribution in QED and demonstrate the efficiency of the MHV technique in perturbative QCD calculations. The gluonic two particle correlation function is highly suggestive of that measured in high-multiplicity $pp$ and $pA$ collisions, with a tight correlation in angle but broad correlation in rapidity. Further, the autocorrelation generated by the non-Abelian correlation can provide a significant non-hydrodynamical source of $v_2$ in these high multiplicity $pp$ and $pA$ collisions. Finally, these two gluon correlations can be used to calibrate Monte Carlo shower codes for a more accurate description of QCD processes in $pp$ collisions.

    hep-phnucl-th2 citations
16. 16*

    Constraining Parton Distribution Functions from Neutral Current Drell-Yan Measurements

    E. Accomando🇬🇧 · J. Fiaschi🇬🇧 · F. Hautmann🇬🇧 · S. Moretti🇬🇧

    We study the cross section \sigma and Forward-Backward asymmetry A_{FB} in the process pp \to \gamma^*,Z \to \ell^+\ell^- (with \ell=e,\mu) for determinations of Parton Distribution Functions (PDFs) of the proton. We show that, once mapped in the invariant mass of the di-lepton final state, M({\ell\ell}), both observables, \sigma and A_{FB}, display a statistical error which is presently competitive with that assigned to the existing PDF sets and which will rapidly become smaller than the latter as the luminosity being accumulated at Run-II of the LHC grows. This statement is applicable to both on-peak and off-peak M({\ell\ell}) regions, both (just) below and above it, thereby offering a means of constraining the quark PDFs over a sizeable (x,Q^2) range.

    hep-phPRD(2018)·36 citations
17. 17*

    Non-perturbative electroweak-scalegenesis on the test bench of dark matter detection

    Jisuke Kubo🇯🇵 · Qidir Maulana Binu Soesanto🇯🇵 · Masatoshi Yamada🇩🇪

    We revisit a recently proposed scale invariant extension of the standard model, in which the scalar bi-linear condensate in a strongly interacting hidden sector dynamically breaks scale symmetry, thereby triggering electroweak symmetry breaking. Relaxing the previously made assumption on $U(N_f)$ flavor symmetry we find that the presence of the would-be dark matter candidate opens a new annihilation process of dark matter at finite temperature, such that the model can satisfy stringent constraints of the future experiments of the dark matter direct detection.

    hep-phhep-thEPJC(2018)·10 citations
18. 18*

    Rare top quark decays at a 100 TeV proton-proton collider: $t\to bWZ$ and $t\to hc$

    Andreas Papaefstathiou🇳🇱 · Gilberto Tetlalmatzi-Xolocotzi🇳🇱

    We investigate extremely rare top quark decays at a future proton-proton collider with centre-of-mass energy of 100 TeV. We focus on two decay modes: radiative decay with a $Z$ boson, $t\to bWZ$, and flavour-changing neutral decay with a Higgs boson, $t\to hc$, the former being kinematically suppressed with a branching ratio of $\mathcal{O}(10^{-6})$, and the latter highly loop-suppresed, with a branching ratio of $\mathcal{O}(10^{-15})$. We find that $t\to bWZ$ will be very challenging to observe in top quark pair production, even within well-motivated beyond-the-Standard Model scenarios. For the mode $t\to hc$ we find a stronger sensitivity than that obtained by any future LHC measurement by at least one order of magnitude.

    hep-phEPJC(2018)·24 citations
19. 19*

    Probing light top partners with CP violation

    Giuliano Panico🇪🇸 · Marc Riembau🇪🇸 · Thibaud Vantalon🇩🇪

    We investigate CP-violating effects induced by light top partners in composite Higgs theories. We find that sizable contributions to the dipole moments of the light SM quarks and leptons are generically generated at the two-loop level through Barr-Zee-type diagrams. The present constraints on the electron and neutron electric dipole moments translate into bounds on top partner masses of order few TeV and are competitive with the reach of LHC direct searches. Interestingly, we find that CP-violation effects are sensitive to the same operators that control top partner single production. Near-future improvements in the determination of the electron dipole moment will extend the reach on top partner masses beyond the 5 - 10 TeV range.

    hep-phJHEP(2018)·25 citations
20. 20*

    Novel Constraints on Mixed Dark-Matter Scenarios of Primordial Black Holes and WIMPs

    Sofiane M. Boucenna🇸🇪 · Florian Kuhnel🇸🇪 · Tommy Ohlsson🇸🇪 · Luca Visinelli🇸🇪

    We derive constraints on mixed dark-matter scenarios consisting of primordial black holes (PBHs) and weakly interacting massive particles (WIMPs). In these scenarios, we expect a density spike of the WIMPs that are gravitationally bound to the PBHs, which results in an enhanced annihilation rate and increased indirect detection prospects. We show that such scenarios provide strong constraints on the allowed fraction of PBHs that constitutes the dark matter, depending on the WIMP mass $m_{\chi }$ and the velocity-averaged annihilation cross-section $⟨\sigma v⟩$. For the standard scenario with $m_{\chi }=100\mathrm{GeV}$ and $⟨\sigma v⟩=3\times 10^{-26}{\mathrm{cm}}^3/\mathrm{s}$, we derive bounds that are stronger than all existing bounds for PBHs with masses $10^{-12}{M}_{\odot }\lesssim M_{\mathrm{BH}}\lesssim 10^4{M}_{\odot }$, where $M_{\odot }$ is the solar mass, and mostly so by several orders of magnitude.

    hep-phastro-ph.COgr-qchep-thJCAP(2018)·92 citations
21. 21*

    Accessing Quark Helicity through Dihadron Studies

    Hrayr H. Matevosyan🇦🇺 · Aram Kotzinian🇦🇲 · Anthony W. Thomas🇦🇺

    We present a new proposal to study the helicity-dependent dihadron fragmentation functions (DiFF), which describe the correlations of the longitudinal polarization of a fragmenting quark with the transverse momenta of the produced hadron pair. Recent experimental searches for this DiFF via azimuthal asymmetries in back-to-back hadron pair production in $e^{+}{e}^{-}$ annihilation by the $\mathtt{BELLE}$ Collaboration did not yield a signal. Here we propose a new way to access this DiFF in $e^{+}{e}^{-}$ annihilation, motivated by the recently recalculated cross section of this reaction, which explains why there was in fact no signal for the $\mathtt{BELLE}$ Collaboration to see. In this new approach the azimuthal asymmetry is weighted by the virtual photon's transverse momentum square multiplying sine and cosine functions of difference of azimuthal angles of relative and total momentum for each pair. The integration over the virtual photon's transverse momentum has the effect of separating the convolution between the helicity-dependent DiFFs in the quark and antiquark jets and results in a nonzero collinear expression containing Fourier moments of helicity-dependent DiFFs. A second new measurement is also proposed for two-hadron production in semi-inclusive deep inelastic scattering, where the asymmetry is weighted in a similar way for a single pair. This results in a collinear factorized form of the asymmetry, which includes the quark helicity parton distribution function and the same helicity-dependent DiFF as in $e^{+}{e}^{-}$ production and will allow us to check the universality of this DiFF.

    hep-phhep-exnucl-thPRL(2018)·20 citations
22. 22*

    On the ${\rho }^o$-meson production in the inclusive proton-proton collision

    A.I. Machavariani🇷🇺

    The production of the ${\rho }^o$- meson in the inclusive proton-proton scattering $p_A+p_B\to {\rho }^o+X$ is studied using extension of parton model according to generalized vector meson dominance model (GVMD) in region of small $Q^2=m_{{\rho }^o}^2$ and ${\rho }^o$-meson transverse momentum $\le 1-2GeV/c$. The realistic description of the experimental cross sections of $p_A+p_B\to {\rho }^o+X$ for $4.9\le \sqrt{s}\le 65GeV$ is achieved using an isotropic distribution of the ${\rho }^o$-meson. The resulting density matrix allows one to select values of the quark masses, which lead to the isotropic distribution of the emitted meson. It is demonstrated that the same cross sections of the reaction $p_A+p_B\to {\rho }^o+X$ for the isotropic distribution of the ${\rho }^o$-meson can be obtained with different sets of the quark masses and corresponding coupling constants of the quark-meson vertex functions.

    hep-ph2 citations
23. 23*

    $A_4$ Flavour Model for Dirac Neutrinos: Type I and Inverse Seesaw

    Debasish Borah🇮🇳 · Biswajit Karmakar🇮🇳

    We propose two different seesaw models namely, type I and inverse seesaw to realise light Dirac neutrinos within the framework of $A_4$ discrete flavour symmetry. The additional fields and their transformations under the flavour symmetries are chosen in such a way that naturally predicts the hierarchies of different elements of the seesaw mass matrices in these two types of seesaw mechanisms. For generic choices of flavon alignments, both the models predict normal hierarchical light neutrino masses with the atmospheric mixing angle in the lower octant. Apart from predicting interesting correlations between different neutrino parameters as well as between neutrino and model parameters, the model also predicts the leptonic Dirac CP phase to lie in a specific range -$\pi /3$ to $\pi /3$. While the type I seesaw model predicts smaller values of absolute neutrino mass, the inverse seesaw predictions for the absolute neutrino masses can saturate the cosmological upper bound on sum of absolute neutrino masses for certain choices of model parameters.

    hep-phPLB(2018)·86 citations
24. 24*

    The electromagnetic form factors of $\Lambda$ hyperon in $e^{+}{e}^{-}\to \bar{\Lambda }\Lambda$

    Yongliang Yang🇨🇳 · Zhun Lu🇨🇳

    We study the electromagnetic form factors of $\Lambda$ hyperon in the timelike region using the recent experimental data in the exclusive production of $\bar{\Lambda }\Lambda$ pair in electron-position annihilation. We present a pQCD inspired parametrization of $G_E(s)$ and $G_M(s)$ with only two parameters, and we consider a suppression mechanism of the electric form factor $G_E(s)$ compared to the magnetic form factor $G_M(s)$. The parameters are determined through fitting our parametrization to the effective form factor data in the reaction $e^{+}{e}^{-}\to \bar{\Lambda }\Lambda$. Except the threshold region, our parametrization can reproduce satisfactorily the known behavior of the existing data from the BarBar, DM2 and BESIII Collaborations. We also predict the double spin polarization observables $A_{xx}$, $A_{yy}$ and $A_{zz}$ in $e^{+}{e}^{-}\to \bar{\Lambda }\Lambda$.

    hep-phMod.Phys.Lett.A(2018)·13 citations
25. 25*

    CNO Neutrino Grand Prix: The race to solve the solar metallicity problem

    David G. Cerdeno🇬🇧 · Jonathan H. Davis🇬🇧 · Malcolm Fairbairn🇬🇧 · Aaron C. Vincent🇬🇧

    Several next-generation experiments aim to make the first measurement of the neutrino flux from the Carbon-Nitrogen-Oxygen (CNO) solar fusion cycle. We calculate how much time these experiments will need to run for in order to measure this flux with enough precision to tell us the metal content of the Sun's core, and thereby help to solve the solar metallicity problem. For experiments looking at neutrino-electron scattering, we find that SNO+ will measure this CNO neutrino flux with enough precision after five years in its pure scintillator mode, provided its ${}^{210}$Bi background is measured to 1% accuracy. By comparison, a 100~ton liquid argon experiment such as Argo will take ten years in Gran Sasso lab, or five years in SNOLAB or Jinping. Borexino could obtain this precision in ten years, but this projection is very sensitive to background assumptions. For experiments looking at neutrino-nucleus scattering, the best prospects are obtained for low-threshold solid state detectors (employing either germanium or silicon). These would require new technologies to lower the experimental threshold close to detection of single electron-hole pairs, and exposures beyond those projected for next-generation dark matter detectors.

    hep-phastro-ph.SRhep-exphysics.ins-detJCAP(2018)·31 citations
26. 26*

    Axion Inflation, Proton Decay and Leptogenesis in $SU(5)\times U(1{)}_{PQ}$

    Sofiane M. Boucenna🇸🇪 · Qaisar Shafi🇺🇸

    We implement inflation in a non-supersymmetric SU(5) model based on a non-minimal coupling of the axion field to gravity. The isocurvature fluctuations are adequately suppressed, axions comprise the dark matter, proton lifetime estimates are of order 8e34-3e35 years, and the observed baryon asymmetry arises via non-thermal leptogenesis. The presence of low scale colored scalars ensures unification of the Standard Model gauge couplings and also helps in stabilizing the electroweak vacuum.

    hep-phastro-ph.COPRD(2018)·33 citations
27. 27*

    Mass shift of charmonium states in $\bar{p}A$ collision

    Gy. Wolf🇭🇺 · G. Balassa🇭🇺 · P. Kovács🇭🇺 · M. Zétényi🇭🇺 · S.H. Lee🇰🇷

    The masses of the low lying charmonium states, namely, the $J/\Psi$, $\Psi (3686)$, and $\Psi (3770)$ are shifted downwards due to the second order Stark effect. In $\bar{p}+\text{Au}$ collisions at $6-10$ GeV we study their in\,-\,medium propagation. The time evolution of the spectral functions of these charmonium states is studied with a Boltzmann\,-\,Uehling\,-\,Uhlenbeck (BUU) type transport model. We show that their in\,-\,medium mass shift can be observed in the dilepton spectrum. Therefore, by observing the dileptonic decay channel of these low lying charmonium states, especially for $\Psi (3686)$, we can gain information about the magnitude of the gluon condensate in nuclear matter. This measurement could be performed at the upcoming PANDA experiment at FAIR.

    hep-phPLB(2018)·15 citations
28. 28*

    On Profiles of Boson Stars with Self-Interactions

    Felix Kling🇺🇸 · Arvind Rajaraman🇺🇸

    Under the influence of gravity, light scalar fields can form bound compact objects called boson stars. We use the technique of matching asymptotic expansions to obtain the profile for boson stars where the constituent particles have self-interactions. We obtain parametric representations of these profiles as a function of the self-interactions, including the case of very strong self-interactions. We show that our methods agree with solutions obtained by purely numerical methods. Significant distortions are found as compared to the noninteracting case.

    hep-phastro-ph.GAgr-qcPRD(2018)·39 citations
29. 29*

    Two-loop amplitudes for processes $gg\to Hg,qg\to Hq$ and $q\bar{q}\to Hg$ at large Higgs transverse momentum

    Kirill Kudashkin🇩🇪 · Kirill Melnikov🇩🇪 · Christopher Wever🇩🇪

    We compute the two-loop QCD corrections to amplitudes for processes $gg\to Hg,qg\to Hq$ and $q\bar{q}\to Hg$ in the limit when the Higgs transverse momentum is larger than the top quark mass, $p_{\perp }\gg m_t$. These amplitudes are important ingredients for understanding higher-order QCD effects on Higgs transverse momentum distribution at large $p_{\perp }$.

    hep-phJHEP(2018)·43 citations
30. 30*

    Consequences of minimal seesaw with complex $\mu \tau$ antisymmetry of neutrinos

    Rome Samanta🇮🇳 · Probir Roy🇮🇳 · Ambar Ghosal🇮🇳

    We propose a complex extension of $\mu \tau$ permutation antisymmetry in the neutrino Majorana matrix $M_{\nu }$. The latter can be realized for the Lagrangian by appropriate CP transformations on the neutrino fields. The resultant form of $M_{\nu }$ is shown to be simply related to that with a complex (CP) extension of $\mu \tau$ permutation symmetry, with identical phenomenological consequences, though their group theoretic origins are quite different. We investigate those consequences in detail for the minimal seesaw induced by two strongly hierarchical right-chiral neutrinos $N_1$ and $N_2$ with the result that the Dirac phase is maximal while the two Majorana phases are either 0 or $\pi$. We further provide an uptodate discussion of the $\beta \beta 0\nu$ process vis-a-vis ongoing and forthcoming experiments. Finally, a thorough treatment is given of baryogenesis via leptogenesis in this scenario, primarily with the assumption that the lepton asymmetry produced by the decays of $N_1$ only matters here with the asymmetry produced by $N_2$ being washed out. Tight upper and lower bounds on the mass of $N_1$ are obtained from the constraint of obtaining the correct observed range of the baryon asymmetry parameter and the role played by $N_2$ is elucidated thereafter. The mildly hierarchical right-chiral neutrino case (including the quasidegenerate possibility) is discussed in an Appendix.

    hep-phJHEP(2018)·26 citations
31. 31*

    Generation of the relic neutrino asymmetry in a hot plasma of the early Universe

    Victor B. Semikoz (1)🇷🇺 · Maxim Dvornikov (1 and 2) ((1) IZMIRAN, (2) Tomsk State University)🇷🇺

    The neutrino asymmetry in the early universe plasma, $n_{\nu }-n_{\bar{\nu }}$, is calculated both before and after the electroweak phase transition (EWPT). In the Standard Model before EWPT, the leptogenesis is well known to be driven by the abelian anomaly in a massless hypercharge field. The generation of the neutrino asymmetry in the Higgs phase after EWPT, in its turn, has not been considered previously because of the absence of any quantum anomaly in an external electromagnetic field for such electroneutral particles as neutrino, unlike the Adler-Bell-Jackiw anomaly for charged left and right polarized massless electrons in the same electromagnetic field. Using the neutrino Boltzmann equation, modified by the Berry curvature term in the momentum space, we establish the violation of the macroscopic neutrino current in plasma after EWPT and exactly reproduce the nonconservation of the lepton current in the symmetric phase before EWPT arising in quantum field theory due to the nonzero lepton hypercharge and corresponding triangle anomaly in an external hypercharge field. In the last case, the non-conservation of the lepton current is derived through the kinetic approach without a computation of corresponding Feynman diagrams. Then the new kinetic equation is applied for the calculation of the neutrino asymmetry accounting for the Berry curvature and the electroweak interaction with background fermions in the Higgs phase. Such an interaction generates a neutrino asymmetry through the electroweak coupling of neutrino currents with electromagnetic fields in plasma, which is $\sim G_{\mathrm{F}}^2$. It turns out that this effect is especially efficient for maximally helical magnetic fields.

    hep-phastro-ph.COInt.J.Mod.Phys.D(2018)·2 citations
32. 32*

    One constraint to kill them all?

    Luca Di Luzio🇬🇧 · Matthew Kirk🇬🇧 · Alexander Lenz🇬🇧

    Many new physics models that explain the intriguing anomalies in the $b$-quark flavour sector are severely constrained by $B_s$-mixing, for which the Standard Model prediction and experiment agreed well until recently. The most recent FLAG average of lattice results for the non-perturbative matrix elements points, however, in the direction of a small discrepancy in this observable. Using up-to-date inputs from standard sources such as PDG, FLAG and one of the two leading CKM fitting groups to determine $\Delta M_s^{\mathrm{SM}}$, we find a severe reduction of the allowed parameter space of $Z^{\prime }$ and leptoquark models explaining the $B$-anomalies. Remarkably, in the former case the upper bound on the $Z^{\prime }$ mass approaches dangerously close to the energy scales already probed by the LHC. We finally identify some model building directions in order to alleviate the tension with $B_s$-mixing.

    hep-phPRD(2018)·146 citations
33. 33*

    Magnetic field generation in dense gas of massive electrons with anomalous magnetic moments electroweakly interacting with background matter

    Maxim Dvornikov (IZMIRAN, Tomsk State University)🇷🇺

    We describe the generation of the electric current flowing along the external magnetic field in the system of massive charged fermions, possessing anomalous magnetic moments and electroweakly interacting with background matter. This current is shown to result in the instability of the magnetic field leading to its growth. Some astrophysical applications are discussed.

    hep-phastro-ph.HEParticle Physics at the Silver Jubilee of…·0 citations
34. 34*

    Seeking Heavy Higgs Bosons through Cascade Decays

    Baradhwaj Coleppa🇮🇳 · Benjamin Fuks🇫🇷 · P. Poulose🇮🇳 · Shibananda Sahoo🇮🇳

    We investigate the LHC discovery prospects for a heavy Higgs boson decaying into the Standard Model Higgs boson and additional weak bosons. We consider a generic model-independent new physics configuration where this decay proceeds via a cascade involving other intermediate scalar bosons and focus on an LHC final-state signature comprised either of four b-jets and two charged leptons or of four charged leptons and two b-jets. We design two analyses of the corresponding signals, and demonstrate that a 5{\sigma} discovery at the 14 TeV LHC is possible for various combinations of the parent and daughter Higgs-boson masses. We moreover find that the Standard Model backgrounds can be sufficiently rejected to guarantee the reconstrution of the parent Higgs boson mass. We apply our analyses to the Type-II Two-Higgs-Doublet Model and identify the regions of the parameter space to which the LHC is sensitive.

    hep-phPRD(2018)·5 citations
35. 35*

    A no-go theorem for non-standard explanations of the $\tau \to K_S\pi {\nu }_{\tau }$ CP asymmetry

    Vincenzo Cirigliano🇺🇸 · Andreas Crivellin🇨🇭 · Martin Hoferichter🇺🇸

    The CP asymmetry in $\tau \to K_S\pi {\nu }_{\tau }$, as measured by the BaBar collaboration, differs from the Standard Model prediction by $2.8\sigma$. Most non-standard interactions do not allow for the required strong phase needed to produce a non-vanishing CP asymmetry, leaving only new tensor interactions as a possible mechanism. We demonstrate that, contrary to previous assumptions in the literature, the crucial interference between vector and tensor phases is suppressed by at least two orders of magnitude due to Watson's final-state-interaction theorem. Furthermore, we find that the strength of the relevant CP-violating tensor interaction is strongly constrained by bounds from the neutron electric dipole moment and $D$-$\bar{D}$ mixing. These observations together imply that it is extremely difficult to explain the current $\tau \to K_S\pi {\nu }_{\tau }$ measurement in terms of physics beyond the Standard Model originating in the ultraviolet.

    hep-phhep-exnucl-thPRL(2018)·80 citations
36. 36*

    Universal Properties of Pseudoscalar Mediators

    Martin Bauer🇩🇪 · Martin Klassen🇩🇪 · Valentin Tenorth🇩🇪

    We discuss universal signals of consistent models of pseudoscalar mediators for collider searches for Dark Matter. Keeping only the degrees of freedom that can not be decoupled due to consistency conditions, we present a universality class of simplified models with pseudoscalar mediators and renormalizable couplings to Standard Model fields. We compute stability and perturbativity constraints, constraints from electroweak precision measurements, collider searches for new heavy particles as well as constraints from relic density measurements and indirect detection experiments searching for signals of Dark Matter annihilation into photons. We find that the mono-$Z$ final state is the strongest, universal signal of this class of models, with additional signatures present in the different ultraviolet completions that can be used to distinguish between them.

    hep-phJHEP(2018)·40 citations
37. 37*

    Detection of Light Dark Matter With Optical Phonons in Polar Materials

    Simon Knapen🇺🇸 · Tongyan Lin🇺🇸 · Matt Pyle🇺🇸 · Kathryn M. Zurek🇺🇸

    We show that polar materials are excellent targets for direct detection of sub-GeV dark matter due to the presence of gapped optical phonons as well as acoustic phonons with high sound speed. We take the example of Gallium Arsenide (GaAs), which has the properties needed for experimental realization, and where many results can be estimated analytically. We find GaAs has excellent reach to dark photon absorption, can completely cover the freeze-in benchmark for scattering via an ultralight dark photon, and is competitive with other proposals to detect sub-MeV dark matter scattering off nuclei.

    hep-phastro-ph.COhep-exPLB(2018)·242 citations
38. 38*

    Let there be light from a second light Higgs doublet

    Ulrich Haisch🇬🇧 · Augustinas Malinauskas🇬🇧

    In this article, we demonstrate that the unexpected peak at around $95\mathrm{GeV}$ as seen recently by CMS in the di-photon final state can be explained within the type-I~two-Higgs-doublet model by means of a moderately-to-strongly fermiophobic CP-even Higgs $H$. Depending on the Higgs mass spectrum, the production of such~a~$H$ arises dominantly from vector boson fusion or through a cascade in either $pp\to t\bar{t}$ with $\stackrel{(-)}{t}\to H^{\pm }\stackrel{(-)}{b}\to W^{\pm \ast }H\stackrel{(-)}{b}$ or $pp\to A$ with $A\to W^{\mp }{H}^{\pm }\to W^{\mp }{W}^{\pm }H$ or via $pp\to W^{\pm \ast }\to H^{\pm }H$. In this context, we also discuss other Higgs anomalies such as the LEP excess in Higgsstrahlung and the observation of enhanced rates in $t\bar{t}h$ at both the Tevatron and the LHC, showing that parameters capable of explaining the CMS di-photon signal can address the latter deviations as well. The Higgs spectra that we explore comprise masses between $80\mathrm{GeV}$ and $350\mathrm{GeV}$. While at present all constraints from direct and indirect searches for spin-0 resonances can be shown to be satisfied for such light Higgses, future LHC data will be able to probe the parameter space that leads to a simultaneous explanation of the discussed anomalies.

    hep-phhep-exJHEP(2018)·79 citations
39. 39*

    Semileptonic decays and $|V_{xb}|$ determinations

    Giulia Ricciardi🇮🇹

    We briefly summarize up-to-date results on the determination of the parameters of the Cabibbo-Kobayashi-Maskawa matrix $|V_{cb}|$ and $|V_{ub}|$, which play an important role in the unitarity triangle and in testing the Standard Model, and recent results on semileptonic $B$ meson decays involving a $\tau$ lepton.

    hep-phEPJ Web Conf.(2018)·5 citations
40. 40*

    CGC/saturation approach: soft interaction at the LHC energies

    E. Gotsman (Tel Aviv U.)🇮🇱 · E. Levin (Tel Aviv U./UTFSM)🇮🇱 · I.Potashnikova (UTFSM)🇨🇱

    In this paper we demonstrate that our model which is based on the CGC/saturation approach, is able to describe the soft interaction collisions including the new TOTEM prelimenary data at 13 TeV. We believe that this strengthens the argument that the CGC/saturation approach is the only viable candidate for an effective theory for high energy QCD.

    hep-phPLB(2018)·13 citations
41. 41*

    Chiral Light Front Perturbation Theory and the Flavor Dependence of the Light-Quark Nucleon Sea

    Mary Alberg🇺🇸 · Gerald A. Miller🇺🇸

    The light-quark flavor dependence of the proton sea has been of great interest for many years because of its close connection with non-perturbative effects. One hypothesis is that this dependence arises from the pion cloud of the proton. We apply light cone perturbation theory and experimental constraints to a chiral Lagrangian to compute the relevant Fock-space components of the nucleon wave function with well-defined uncertainties. Existing experimental information regarding the light flavor sea is studied, and predictions for future experimental results are provided. Future experiments have the ability to rule out this hypothesis and have profound implications for understanding the nucleon-nucleon force.

    ↳ nucl-thhep-phnucl-exPRC(2019)·27 citations
42. 42*

    New magnetic field instability and magnetar bursts

    Maxim Dvornikov (IZMIRAN, Tomsk State University)🇷🇺

    We consider the system of massive electrons, possessing nonzero anomalous magnetic moments, which electroweakly interact with background neutrons under the influence of an external magnetic field. The Dirac equation for such electrons is exactly solved. Basing on the obtained solution, we find that a nonzero electric current of these electrons can flow along the magnetic field. Accounting for the new current in the Maxwell equations, we demonstrate that a magnetic field in this system appears to be unstable. Then we consider a particular case of a degenerate electron gas, which may well exist in a neutron star, and show that a seed magnetic field can be amplified by more than one order of magnitude. Finally we discuss the application of our results for the explanation of the electromagnetic radiation emitted by magnetars.

    ↳ astro-ph.HEhep-phProceedings of the 52nd Rencontres de Mor…·0 citations
43. 43*

    An exact solution to the Bertsch problem and the non-universality of the Unitary Fermi Gas

    E. Ruiz Arriola🇪🇸 · S. Szpigel🇧🇷 · V. S. Timoteo🇧🇷

    We analyze the universality of the Unitary Fermi Gas in its ground state from a Wilsonian renormalization point of view and compute the effective range dependence of the Bertsch parameter $\xi$ exactly. To this end we construct an effective block-diagonal two-body separable interaction with the Fermi momentum as a cut-off which reduces the calculation to the mean field level. The interaction is separable in momentum space and is determined by Tabakin's inverse scattering formula. For a vanishing effective range we get $\xi =\frac{176}{9\pi }-\frac{17}{3}=0.56$. By using phase-equivalent similarity transformations we can show that there is a class of exact solutions with any value in the range $0.56\ge \xi \ge -1/3$.

    ↳ cond-mat.quant-gashep-phnucl-th2 citations
44. 44*

    A new scheme for color confinement and violation of the non-Abelian Bianchi identities

    Tsuneo Suzuki🇯🇵 · Katsuya Ishiguro🇯🇵 · Vitaly Bornyakov🇷🇺

    A new scheme for color confinement in QCD due to violation of the non-Abelian Bianchi identities proposed earlier is revised. The violation of the non-Abelian Bianchi identities (VNABI) $J_{\mu }$ is equal to Abelian-like monopole currents $k_{\mu }$ defined by the violation of the Abelian-like Bianchi identities. VNABI satisfies ${\partial }_{\mu }{J}_{\mu }=0$. There are $N^2-1$ conserved magnetic charges in $SU(N)$ QCD. The charge of each component of VNABI is assumed to satisfy the Dirac quantization condition. %%%%% Each color component of the non-Abelian electric field $E^a$ is squeezed by the corresponding color component of the solenoidal current $J_{\mu }^a$. Then only the color singlets alone can survive as a physical state and non-Abelian color confinement is realized. Numerical studies are done in the framework of $SU(2)$ lattice gauge theory. We adopt an Abelian-like definition of monopole following DeGrand-Toussaint as a lattice version of VNABI. To reduce severe lattice artifacts, we introduce various techniques of smoothing the thermalized vacuum such as the maximal center gauge (MCG) fixing. We measure the density $\rho (a(\beta ),n)=\sqrt{(k_n^1{)}^2+(k_n^2{)}^2+(k_n^3{)}^2}/(4\sqrt{4}V{b}^3)$, where $k_n^a$ is an $n$ blocked monopole in the color direction $a$ and $b=na(\beta )$ is the blocked lattice spacing. Beautiful scaling behaviors are seen when we plot $\rho (a(\beta ),n)$ versus $b=na(\beta )$. A single universal curve $\rho (b)$ is found from $n=1\sim 12$, which suggests that $\rho (a(\beta ),n)$ is a function of $b=na(\beta )$ alone. The universal curve seems independent of a gauge fixing procedure used to smooth the lattice vacuum when the scaling is obtained. The scaling shows that the lattice definition of VNABI has the continuum limit.

    ↳ hep-lathep-phhep-thPRD(2018)·15 citations
45. 45*

    Status of the Theoretical Calculation of Nuclear Electric Dipole Moment

    Nodoka Yamanaka🇫🇷

    The electric dipole moment is a very sensitive probe of CP violation beyond the standard model. Light nuclei are particularly interesting since the CP violation may be enhanced by nuclear many-body effects. In this proceeding, we present the current status of the theoretical evaluations of the electric dipole moment of light nuclei in the ab initio approach and in the cluster model. We add the preliminary result of the evaluation of the electric dipole moment of ${}^7$Li which is treated in a cluster model with a triton.

    ↳ nucl-thhep-exhep-phnucl-exJPS Conf.Proc.(2018)·2 citations
46. 46*

    Quantum implications of a scale invariant regularisation

    D. M. Ghilencea🇷🇴

    We study scale invariance at the quantum level (three loops) in a perturbative approach. For a scale-invariant classical theory the scalar potential is computed at three-loop level while keeping manifest this symmetry. Spontaneous scale symmetry breaking is transmitted at quantum level to the visible sector (of $\varphi$) by the associated Goldstone mode (dilaton $\sigma$) which enables a scale-invariant regularisation and whose vev $⟨\sigma ⟩$ generates the subtraction scale ($\mu$). While the hidden ($\sigma$) and visible sector ($\varphi$) are classically decoupled in $d=4$ due to an enhanced Poincaré symmetry, they interact through (a series of) evanescent couplings $\propto {ϵ}^k$, ($k\ge 1$), dictated by the scale invariance of the action in $d=4-2ϵ$. At the quantum level these couplings generate new corrections to the potential, such as scale-invariant non-polynomial effective operators ${\varphi }^{2n+4}/{\sigma }^{2n}$ and also log-like terms ($\propto {\ln }^k\sigma$) restoring the scale-invariance of known quantum corrections. The former are comparable in size to "standard" loop corrections and important for values of $\varphi$ close to $⟨\sigma ⟩$. For $n=1,2$ the beta functions of their coefficient are computed at three-loops. In the infrared (IR) limit the dilaton fluctuations decouple, the effective operators are suppressed by large $⟨\sigma ⟩$ and the effective potential becomes that of a renormalizable theory with explicit scale symmetry breaking by the "usual" DR scheme (of $\mu =$constant).

    ↳ hep-thhep-phPRD(2018)·25 citations
47. 47*

    Associated production of top quarks with the Higgs boson at $\sqrt{s}=13$ TeV

    Georgios Konstantinos Krintiras (On behalf of the CMS Collaboration)🇧🇪

    The top quark, being the heaviest elementary fermion known in the Standard model, has the largest coupling to the Higgs boson. The associated production of top quarks with the Higgs boson, either in pairs (t$\bar{\mathrm{t}}$H) or singly (tH), provides direct experimental access to the top-Higgs coupling $y_{\mathrm{t}}$. The t$\bar{\mathrm{t}}$H (tH) production mode, while proceeding at a rate of about 100 (1000) times smaller than gluon fusion, bears a highly distinctive experimental signature, which includes leptons and/or jets from the decay of the two (single) top quarks. The latest results of ttH searches at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of up to $35.9{\mathrm{fb}}^{-1}$ as collected from CMS are shown and tantalizing evidence is found for measuring this crucial process with sufficient precision. However, higher precision data set is needed in order to confirm or disprove the previous observed excess. Initial searches for tH production mode at a center-of-mass energy of 13 TeV achieve comparable sensitivity to that of the Run 1 analysis.

    ↳ hep-exhep-phPoS(2018)·0 citations
48. 48*

    Constraining QCD multijet background in the $\text{t}$-channel single-top quark production at $\sqrt{s}=13TeV$

    Georgios Konstantinos Krintiras (On behalf of the CMS Collaboration)🇧🇪

    Precision measurement of the cross section for single top production is an important test of the Standard Model (SM). The purity of the collected data in single top events is limited by the understanding of the shape and yield of background contributions. Besides electroweak and $\mathrm{t}\bar{\mathrm{t}}$ processes, QCD multijet events constitute a non-negligible background for the considered signal bq${}^{\prime }\to$ tq ($\text{t}$-channel) process. The data-driven technique for constraining QCD contribution, employed in the measurement of the $\text{t}$-channel single top-quark cross section using the very first LHC proton-proton collisions at $\sqrt{s}=13TeV$ with the CMS detector, is described. The dataset corresponds to an integrated luminosity of $\mathcal{L}=42p{b}^{-1}$.

    ↳ hep-exhep-phPoS(2016)·0 citations
49. 49*

    No axion-like particles from core-collapse supernovae?

    Ignazio Bombaci · Giorgio Galanti🇮🇹 · Marco Roncadelli🇮🇹

    A strong bound on the properties of axion-like particles (ALPs) has been set by assuming that ALPs are emitted by the protoneutron star just before the core-bounce in Galactic core-collapse supernovae, and that these ALPs subsequently convert to $\gamma$-ray photons which ought to be detected by a $\gamma$-ray mission. This argument has been applied to supernova 1987A to derive the bound on the ALP-photon coupling $g_{a\gamma \gamma }\lesssim 5.3\cdot 10^{-12}{\mathrm{GeV}}^{-1}$ for an ALP mass $m_a\lesssim 4.4\cdot 10^{-10}\mathrm{eV}$, and can be applied to the next Galactic supernova to derive the even stronger bound $g_{a\gamma \gamma }\lesssim 2\cdot 10^{-13}{\mathrm{GeV}}^{-1}$ for an ALP mass $m_a\lesssim 10^{-9}\mathrm{eV}$. We carefully analyze the considered ALP production mechanism and find that it is oversimplified to an unacceptable extent. By taking into account the minimal ingredients required by a realistic analysis, we conclude that the previous results are doomed to failure. As a consequence, all papers quoting the above bound should be properly revised. Yet, since we are unable to rule out the possibility that protoneutron stars emit ALPs, in case a core-collapse supernova explodes in the Galaxy the $\gamma$-ray satellite missions active at that time should look for photons possibly coming from the supernova.

    ↳ astro-ph.HEhep-ph8 citations
50. 50*

    Electromagnetic Radiation in a Semi-Compact Space

    Satoshi Iso🇯🇵 · Noriaki Kitazawa🇯🇵 · Sumito Yokoo🇯🇵

    In this note, we investigate the electromagnetic radiation emitted from a revolving point charge in a compact space. If the point charge is circulating with an angular frequency ${\omega }_0$ on the $(x,y)$-plane at $z=0$ with boundary conditions, $x\sim x+2\pi R$ and $y\sim y+2\pi R$, it emits radiation into the $z$-direction of $z$ in $[-\infty ,+\infty ]$. We find that the radiation shows discontinuities as a function of ${\omega }_{0}R$ at which a new propagating mode with a different Fourier component appears. For a small radius limit ${\omega }_{0}R\ll 1$, all the Fourier modes except the zero mode on $(x,y)$-plane are killed, but an effect of squeezing the electric field totally enhances the radiation. In the large volume limit ${\omega }_{0}R\to \infty$, the energy flux of the radiation reduces to the expected Larmor formula.

    ↳ hep-thhep-phPLA(2018)·1 citation
51. 51*

    Possible ${\eta }^{\prime }d$ bound state and its $s$-channel formation in the $\gamma d\to \eta d$ reaction

    Takayasu Sekihara (JAEA, Ibaraki)🇯🇵 · Hiroyuki Fujioka (Kyoto U.)🇯🇵 · Takatsugu Ishikawa (ELPH, Tohoku Univ.)🇯🇵

    We theoretically investigate a possibility of an ${\eta }^{\prime }d$ bound state and its formation in the $\gamma d\to \eta d$ reaction. First, in the fixed center approximation to the Faddeev equations we obtain an ${\eta }^{\prime }d$ bound state with a binding energy of 25 MeV and width of 19 MeV, where we take the ${\eta }^{\prime }N$ interaction with a coupling to the $\eta N$ channel from the linear $\sigma$ model. Then, in order to investigate the feasibility from an experimental point of view, we calculate the cross section of the $\gamma d\to \eta d$ reaction at the photon energy in the laboratory frame around 1.2 GeV. As a result, we find a clear peak structure with the strength $\sim$ 0.2 nb/sr, corresponding to a signal of the ${\eta }^{\prime }d$ bound state in case of backward $\eta$ emission. This structure will be prominent because a background contribution coming from single-step $\eta$ emission off a bound nucleon is highly suppressed. In addition, the signal can be seen even in case of forward $\eta$ emission as a bump or dip, depending on the relative phase between the bound-state formation and the single-step background.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2018)·5 citations
52. 52*

    Why {\em Explicit} Strangeness Is Not Relevant In Compact Stars

    Mannque Rho🇫🇷

    Drawing largely from my work with co--workers, I present arguments that strangeness does not play an {\it explicit} role in compact-star matter. They are based on the skyrmion description of dense matter combined with Wilsoninan renormalization group approach to kaon nuclear interactions. The key idea is that quark degrees of freedom, carrying strangeness, can be traded in by topology for hadron degrees of freedom.

    ↳ nucl-thastro-ph.HEhep-ph1 citation
53. 53*

    Origin and dynamics of the Primordial Magnetic field in a parity violating plasma

    Arun Kumar Pandey

    In this thesis, we have studied the generation and evolution of the magnetic field in the early Universe. We investigated the generation of magnetic fields in the presence of chiral symmetry and gravitational anomaly. We have used modified kinetic theory by Berry curvature and derived expressions for magnetic and vortical conductivities. We have also shown that there are two length scales: kinetic and viscous, which is one of the important results. In the latter part of the thesis, we have shown the effect of second-order viscous effects on the modes of the magnetic fields.

    ↳ astro-ph.COastro-ph.GAhep-phphysics.plasm-ph4 citations
54. 54*

    Search for a light radion at HL-LHC and ILC250

    Francois Richard🇫🇷

    With the data collected by LHC at 13 TeV, the CMS collaboration has searched for low mass resonances decaying into two photons. This has resulted in the observation of 3 sd excess around 95 GeV, reminiscent of an indication obtained at LEP2 by combining the Higgs boson searches of the four LEP experiments. These observations, marginally significant, motivate the present study which shows how HL-LHC and ILC250 could search for a radion, the lightest new particle predicted within the Randall Sundrum (RS) model. ILC operating at a centre of mass energy of 250 GeV and with an integrated luminosity surpassing LEP2 by three orders of magnitude, could become the ideal machine to study a light radion and to observe, with very high accuracy, how it mixes with the Higgs boson and modifies the various couplings.

    ↳ hep-exhep-ph34 citations
55. 55*

    Experimental overview of spectroscopy from heavy hadron decays

    Ignacio Bediaga🇧🇷 · Patricia C Magalhães🇧🇷

    We present and discuss some experimental approaches involving spectroscopy from heavy meson decays going to light mesons. In particular we emphasis the scalar resonance $f_0(980)$, which have different well determined parameter of mass and width obtained from $J/\psi$ and D decays. We will also show how the CP violation observed in charmless three body decay can be used as tool to understand hadron hadron interaction at low mass region

    ↳ hep-exhep-phPoS(2018)·1 citation
56. 56*

    LIGO Lo(g)Normal MACHO: Primordial Black Holes survive SN lensing constraints

    Juan Garcia-Bellido🇪🇸 · Sebastien Clesse🇧🇪 · Pierre Fleury🇨🇭

    It has been claimed in Ref.[arXiv:1712.02240] that massive primordial black holes (PBH) cannot constitute all of the dark matter (DM), because their gravitational-lensing imprint on the Hubble diagram of type Ia supernovae (SN) would be incompatible with present observations. In this paper, we critically review those constraints and find several caveats on the analysis. First of all, the constraints on the fraction $\alpha$ of PBH in matter seem to be driven by a very restrictive choice of priors on the cosmological parameters. In particular, the degeneracy between ${\Omega }_{\mathrm{M}}$ and $\alpha$ is ignored and thus, by fixing ${\Omega }_{\mathrm{M}}$, transferred the constraining power of SN magnitudes to $\alpha$. Furthermore, by considering more realistic physical sizes for the type-Ia supernovae, we find an effect on the SN lensing magnification distribution that leads to significantly looser constraints. Moreover, considering a wide mass spectrum of PBH, such as a lognormal distribution, further softens the constraints from SN lensing. Finally, we find that the fraction of PBH that could constitute DM today is bounded by $f_{\mathrm{PBH}}<1.09(1.38)$, for JLA (Union 2.1) catalogs, and thus it is perfectly compatible with an all-PBH dark matter scenario in the LIGO band.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phPhys.Dark Univ.(2018)·85 citations
57. 57*

    Quantum Corrections to the Gravitational Backreaction

    Iberê Kuntz🇬🇧

    Effective Field Theory techniques are used to study the leading order quantum corrections to the gravitational wave backreaction. The effective stress-energy tensor is calculated and it is shown that it has a non-vanishing trace that contributes to the cosmological constant. By comparing the result obtained with LIGO's data, the first bound on the amplitude of the massive mode is found: $ϵ<1.4\times 10^{-33}$.

    ↳ gr-qchep-phhep-thEPJC(2018)·22 citations
58. 58*

    Decoherence of Gravitational Wave Oscillations in Bigravity

    Kevin Max🇮🇹 · Moritz Platscher🇩🇪 · Juri Smirnov🇮🇹

    Following up on our recent study, we consider the regime of graviton masses and gravitational wave propagation distances at which decoherence of the wave packets plays a major role for phenomenology. This regime is of particular interest, as it can lead to very striking phenomena of echo events in the gravitational waves coming from coalescence events. The power of the experimental search in this case lies in the fact that it becomes sensitive to a large range of graviton masses, while not relying on a specific production mechanism. We are thus able to place new relevant limits on the parameter space of the graviton mixing angle.

    ↳ gr-qcastro-ph.COhep-phPRD(2018)·27 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.