Mon·Dec 18, 2017Monday·December 18, 2017

1. 01*

   Hybrid Inflation in Quasi-minimal Supergravity with Monotonic Inflationary Potentia

   C. Panagiotakopoulos🇬🇷

   We show how supersymmetric hybrid inflation with scalar spectral index $n_{\mathrm{s}}\simeq 0.96-0.97$ is realized in the context of quasi-minimal supergravity if we insist that the inflationary potential not exhibit any local minima. We also address the problem of the initial conditions for both monotonic and non-monotonic inflationary potentials.

   hep-phPRD(2018)·0 citations
2. 02*

   Radiative neutrino masses in an abelian extension of the Standard Model

   S. F. Mantilla · R. Martinez · J. Muñoz

   The seesaw mechanism is the preferred methodology to obtain light neutrino masses by the introduction of a Majorana mass matrix. Moreover, radiative corrections can be done in order to improve the predictions of the model. However, when such a Majorana mass has no inverse, radiative corrections turn out as the only mechanism to get massive neutrinos. In this letter, it is shown a nonuniversal abelian extension ${\mathrm{U}(1)}_X$ of the Standard Model in which neutrinos acquire masses completely by radiative corrections through one-loop self-energies involving heavier right-handed neutrinos. Moreover, one right-handed neutrino also gets mass through radiative corrections involving Majorana fermions. Finally, some limit cases are drafted depending on the hierarchy among vacuum expectation values and Majorana masses.

   hep-ph7 citations
3. 03*

   Renormalon free part of an ultrasoft correction to the static QCD potential

   Hiromasa Takaura🇯🇵

   Perturbative calculations of the static QCD potential have the $u=3/2$ renormalon uncertainty. In the multipole expansion performed within pNRQCD, this uncertainty at LO is known to get canceled against the ultrasoft correction at NLO. To investigate the net contribution remaining after this renormalon cancellation, we propose a formulation to separate the ultrasoft correction into renormalon uncertainties and a renormalon independent part. We focus on very short distances ${\Lambda }_{\mathrm{QCD}}r\lesssim 0.1$ and investigate the ultrasoft correction based on its perturbative evaluation in the large-${\beta }_0$ approximation. We also propose a method to examine the local gluon condensate, which appears as the first nonperturbative effect to the static QCD potential, without suffering from the $u=2$ renormalon.

   hep-phPLB(2018)·5 citations
4. 04*

   Constraining Born-Infeld-like Nonlinear Electrodynamics Using Hydrogen's Ionization Energy

   P. Niau Akmansoy🇧🇷 · L. G. Medeiros🇧🇷

   In this work, the hydrogen's ionization energy was used to constrain the free parameter $b$ of three Born-Infeld-like electrodynamics namely Born-Infeld itself, Logarithmic electrodynamics and Exponential electrodynamics. An analytical methodology capable of calculating the hydrogen ground state energy level correction for a generic nonlinear electrodynamics was developed. Using the experimental uncertainty in the ground state energy of the hydrogen atom, the bound $b>5.37\times 10^{20}K\frac{V}{m}$, where $K=2$, $4\sqrt{2}/3$ and $\sqrt{\pi }$ for the Born-Infeld, Logarithmic and Exponential electrodynamics respectively, was established. In the particular case of Born-Infeld electrodynamics, the constraint found for $b$ was compared with other constraints present in the literature.

   hep-phhep-thEPJC(2018)·35 citations
5. 05*

   Theoretical Uncertainties in the Calculation of Supersymmetric Dark Matter Observables

   Paul Bergeron🇺🇸 · Pearl Sandick🇺🇸 · Kuver Sinha🇺🇸

   We estimate the current theoretical uncertainty in supersymmetric dark matter predictions by comparing several state-of-the-art calculations within the minimal supersymmetric standard model (MSSM). We consider standard neutralino dark matter scenarios -- coannihilation, well-tempering, pseudoscalar resonance -- and benchmark models both in the pMSSM framework and in frameworks with Grand Unified Theory (GUT)-scale unification of supersymmetric mass parameters. The pipelines we consider are constructed from the publicly available software packages SOFTSUSY, SPheno, FeynHiggs, SusyHD, micrOMEGAs, and DarkSUSY. We find that the theoretical uncertainty in the relic density as calculated by different pipelines, in general, far exceeds the statistical errors reported by the Planck collaboration. In GUT models, in particular, the relative discrepancies in the results reported by different pipelines can be as much as a few orders of magnitude. We find that these discrepancies are especially pronounced for for cases where the dark matter physics relies critically on calculations related to electroweak symmetry breaking, which we investigate in detail, and for coannihilation models, where there is heightened sensitivity to the sparticle spectrum. The dark matter annihilation cross section today and the scattering cross section with nuclei also suffer appreciable theoretical uncertainties, which, as experiments reach the relevant sensitivities, could lead to uncertainty in conclusions regarding the viability or exclusion of particular models.

   hep-phJHEP(2018)·9 citations
6. 06*

   Confidence regions for neutrino oscillation parameters from double-Chooz data

   B. Vargas Perez🇲🇽 · J. García-Ravelo🇲🇽 · Dionisio Tun🇲🇽 · Jorge Garcia Bello🇲🇽 · Jesús Escamilla Roa🇲🇽

   In this work, an independent and detailed statistical analysis of the double-Chooz experiment is performed. To have a thorough understanding of the implications of the double-Chooz data on both oscillation parameters ${\sin }^2(2{\theta }_{13})$ and $\Delta m_{31}^2$, we decided to analyze the data corresponding to the Far detector, with no additional restriction. By doing this, confidence regions and best fit values are obtained for (${\sin }^2(2{\theta }_{13}),\Delta m_{31}^2$). This analysis yields an out-of-order $\Delta m_{31}^2$ minimum, which has already been mentioned in previous works, and it is corrected with the inclusion of additional restrictions. With such restrictions it is obtained that ${\sin }^2(2{\theta }_{13})=0.084_{-0.028}^{+0.030}$ and $\Delta m_{31}^2=2.444_{-0.215}^{+0.187}\times 10^{-3}$ eV${}^2$/c${}^4$. Our analysis allows us to study the effects of the so called "spectral bump" around 5 MeV, it is observed that a variation of this spectral bump may be able to move the $\Delta m_{31}^2$ best fit value, in such a way that $\Delta m_{31}^2$ takes the order of magnitude of the MINOS value. Finally, and with the intention of understanding the effects of the preliminary Near detector data, we performed two different analyses, aiming to eliminate the effects of the energy bump. As a consequence, it is found that unlike the Far Detector analysis, the Near detector data may be able to fully determine both oscillation parameters by itself, resulting in, ${\sin }^2(2{\theta }_{13})=0.095\pm 0.053$ and $\Delta m_{31}^2=2.63_{-1.15}^{+0.98}\times 10^{-3}{\text{eV}}^2/{\text{c}}^4$. The later analyses represent an improvement with respect to previous works, where additional constraints for $\Delta m_{31}^2$ were necessary.

   hep-phPRD(2018)·0 citations
7. 07*

   On the strong effective coupling, glueball and meson ground states

   Gurjav Ganbold🇲🇳

   The phenomena of strong running coupling and hadron mass generating have been studied in the framework of a QCD-inspired relativistic model of quark-gluon interaction with infrared confined propagators. We derived a meson mass equation and revealed a specific new behaviour of the mass-dependent strong coupling ${\hat{\alpha }}_s(M)$ defined in the time-like region. A new infrared freezing point ${\hat{\alpha }}_s(0)=1.03198$ at origin has been found and it did not depend on the confinement scale $\Lambda >0$. Independent and new estimates on the scalar glueball mass, 'radius' and gluon condensate value have been performed. The spectrum of conventional mesons have been calculated by introducing a minimal set of parameters: the masses of constituent quarks and $\Lambda$. The obtained values are in good agreement with the latest experimental data with relative errors less than 1.8 percent. Accurate estimates of the leptonic decay constants of pseudoscalar and vector mesons have been performed.

   hep-ph2 citations
8. 08*

   Study of the rare decays $B_{(}s,d{)}^{\ast }$ arrow $l^{+}{l}^{-}$ in Z' model

   Debika Banerjee🇮🇳 · Priya Maji🇮🇳 · Sukadev Sahoo🇮🇳

   The rare decays $B_{(s,d)}^{\ast }\to l^{+}{l}^{-}$ are important to probe the flavour sector of the standard model and to search new physics beyond the SM. Unlike pseudoscalar B meson, the leptonic decays of vector $B_{(}s,d{)}^{\ast }$ mesons are not chirally supressed which compensates for their short lifetimes, and results significant branching ratios. In this paper, we estimate the branching ratios of $B_{(s,d)}^{\ast }\to l^{+}{l}^{-}$ $(l=e,\mu )$ rare decays in Z' model which is an extension of the SM with an extra U(1)' gauge symmetry. We find that the branching ratios are increased from their corresponding standard model values and vary with the mass of $Z^{\prime }$ boson. Lower is the mass of $Z^{\prime }$ boson, higher is the branching ratio.

   hep-phInt.J.Mod.Phys.A(2017)·9 citations
9. 09*

   Predictions on three-particle azimuthal correlations in proton-proton collisions

   Şener Özönder🇹🇷

   The ridge signal, which is long-ranged in rapidity, in the di-hadron correlations in high-multiplicity p-p and p-A collisions opened up a whole new research area in high-energy QCD. Although the ridge had been observed in A-A collisions and interpreted as a result of the radial flow of quark-gluon plasma, it had not appeared until recently in the data of small collision systems such as p-p and p-A, nor had it been predicted theoretically or seen in the event generators. There are two competing approaches that attempt to explain the systematics of the di-hadron ridge signal; hydrodynamics and gluon saturation physics (color glass condensate/glasma). In this work, we present predictions for the transverse momentum and rapidity dependence of the three-particle correlation function within the gluon saturation physics. Tri-hadron correlations can be measured, and the data can possibly rule out one of the two alternative approaches.

   hep-phnucl-thTurk.J.Phys.(2018)·7 citations
10. 10*

    What can we learn on supernova neutrino spectra with water Cherenkov detectors?

    Andrea Gallo Rosso🇮🇹 · Francesco Vissani🇮🇹 · Maria Cristina Volpe🇫🇷

    We investigate the precision with which the supernova neutrino spectra can be reconstructed in water Cherenkov detectors, in particular the large scale Hyper-Kamiokande and Super-Kamiokande. To this aim, we consider quasi-thermal neutrino spectra modified by the Mikheev-Smirnov-Wolfenstein effect for the case of normal ordering. We perform three 9 degrees of freedom likelihood analyses including first inverse-beta decay only, then the combination of inverse beta decay and elastic scattering on electrons and finally a third analysis that also includes neutral scattering neutrino-oxygen events. A tenth parameter is added in the analyses to account for the theoretical uncertainty on the neutral current neutrino-oxygen cross section. By assuming a 100\% efficiency in Hyper-Kamiokande, we show that one can reconstruct the electron antineutrino average energy and pinching parameter with an accuracy of $\sim 2\%$ and $\sim 7\%$ percent respectively, while the antineutrino integrated luminosity can be pinned down at $\sim 3\%$ percent level. As for the muon and tau neutrinos, the average energy and the integrated luminosity can be measured with $\sim 7\%$ precision. These results represent a significant improvement with respect Super-Kamiokande, particularly for the pinching parameter defining the electron antineutrino spectra. As for electron neutrinos, the determination of the emission parameters requires the addition of supplementary detection channels.

    hep-phastro-ph.HEJCAP(2018)·49 citations
11. 11*

    Asymptotics of the contour of the stationary phase and efficient evaluation of the Mellin-Barnes integral for the F_3 structure function

    A.V. Sidorov🇷🇺 · V.I. Lashkevich🇧🇾 · O.P. Solovtsova🇷🇺

    A new approximation is proposed for the contour of the stationary phase of the Mellin--Barnes integrals in the case of its finite asymptotic behavior as $\mathrm{Re}z\to -\infty$. The efficiency of application of the proposed contour and the quadratic approximation to the contour of the stationary phase is compared by the example of the inverse Mellin transform for the structure function $F_3$. It is shown that, although for a small number of terms $N$ in quadrature formulas used to calculate integrals along these contours, the quadratic contour is more efficient, but for $N>20$ the asymptotic stationary phase integration contour gives better accuracy. The case of the $Q^2$-dependence of the $F_3$ structure function is also considered.

    hep-phPRD(2018)·3 citations
12. 12*

    A study of the excited radial vector meson $\rho$

    Milena Piotrowska🇵🇱 · Francesco Giacosa🇩🇪

    We study the strong and radiative decays of the radial excitation of the $\rho$ meson, with quantum numbers $n$ ${}^{2S+1}{L}_J=2$ ${}^3{S}_1,$ $I=1$, and denoted as ${\rho }_E$, by making use of an effective model. We test different masses: $1.45$ GeV, corresponding to well known assignment ${\rho }_E\equiv \rho (1450)$ state; $1.25$ GeV for the assignment ${\rho }_E\equiv \rho (1250)$ (a resonance whose existence has not yet been confirmed), and $1.35$ GeV, which lies just in the middle between them in order to study the dependence of the results on the mass. The decay widths for different decay processes and two branching ratios of the radially excited meson ${\rho }_E$ were determined and compared to the experimental data reported in the Particle Data Group.

    hep-phPoS(2018)·3 citations
13. 13*

    Fully differential NLO predictions for rare and radiative lepton decays

    Y. Ulrich🇨🇭

    We present a general purpose, parton-level Monte Carlo program for the calculation of the radiative ($L\to \nu \bar{\nu }l+\gamma$) and rare ($L\to \nu \bar{\nu }{l}^{\prime }+l^{+}{l}^{-}$) muon and tau decays at NLO in the effective Fermi theory. In the case of muon, these processes are irreducible Standard Model backgrounds to searches for lepton flavour violation at the PSI experiments MEG and Mu3e as they become indistinguishable from the corresponding signals when the neutrinos carry little energy. Furthermore, we argue that fully differential NLO corrections are very important for the analysis of measurements aiming at the percent level or better. This is especally true if very stringent phase-space cuts are applied. To illustrate this, we use a tension between BaBar's recent measurement of the radiative tau decay and the Standard Model prediction as an example of such an analysis. Finally, we present the branching ratios of the rare tau decay $\tau \to \nu \bar{\nu }{l}^{\prime }{l}^{+}{l}^{-}$ at NLO. We generally find that QED corrections of $\mathcal{O}(10\%)$ are very well possible.

    hep-phhep-exPoS(2018)·5 citations
14. 14*

    $Z_c(3900)/Z_c(3885)$ as a virtual state from $\pi J/\psi -{\bar{D}}^{\ast }D$ interaction

    Jun He🇨🇳 · Dian-Yong Chen🇨🇳

    In this work, we study the $J/\psi \pi$ and ${\bar{D}}^{\ast }D$ invariant mass spectra of the $Y(4260)$ decay to find out the origin of the $Z_c(3900)$ and $Z_c(3885)$ structures. The $J/\psi \pi -{\bar{D}}^{\ast }D$ interaction is studied in a coupled-channel quasipotential Bethe-Saltpeter equation approach, and embedded to the $Y(4260)$ decay process to reproduce both $J/\psi {\pi }^{-}$ and $D^{\ast -}{D}^0$ invariant mass spectra observed at BESIII simultaneously. It is found out that a virtual state at energy about 3870 MeV is produced from the interaction when both invariant mass spectra are comparable with the experiment. The results support that both $Z_c(3900)$ and $Z_c(3885)$ have the same origin, that is, a virtual state from $J/\psi \pi -{\bar{D}}^{\ast }D$ interaction, in which the ${\bar{D}}^{\ast }D$ interaction is more important and the coupling between ${\bar{D}}^{\ast }D$ and $J/\psi \pi$ channels plays a minor role.

    hep-phnucl-thEPJC(2018)·43 citations
15. 15*

    The magnetic moment of the $Z_c(3900)$ as an axialvector tetraquark state with QCD sum rules

    Zhi-Gang Wang🇨🇳

    In this article, we assign the $Z_c^{\pm }(3900)$ to be the diquark-antidiquark type axialvector tetraquark state, study its magnetic moment with the QCD sum rules in the external weak electromagnetic field by carrying out the operator product expansion up to the vacuum condensates of dimension 8. We pay special attention to matching the hadron side with the QCD side of the correlation function to obtain solid duality, the routine can be applied to study other electromagnetic properties of the exotic particles.

    hep-phEPJC(2018)·22 citations
16. 16*

    The exact tree-level calculation of the dark photon production in high-energy electron scattering at the CERN SPS

    S. N. Gninenko🇷🇺 · D. V. Kirpichnikov🇷🇺 · M. M. Kirsanov🇷🇺 · N. V. Krasnikov🇷🇺

    Dark photon ($A^{\prime }$) that couples to the standard model fermions via the kinetic mixing with photons and serves as a mediator of dark matter production could be observed in the high-energy electron scattering $e^{-}+Z\to e^{-}+Z+A^{\prime }$ off nuclei followed by the $A^{\prime }\to invisible$ decay. We have performed the exact, tree-level calculations of the $A^{\prime }$ production cross sections and implemented them in the program for the full simulation of such events in the experiment NA64 at the CERN SPS. Using simulations results, we study the missing energy signature for the bremsstrahlung $A^{\prime }\to$ invisible decay that permits the determination of the $\gamma -A^{\prime }$ mixing strength in a wide, from sub-MeV to sub-GeV, $A^{\prime }$ mass range. We refine and expand our earlier studies of this signature for discovering $A^{\prime }$ by including corrections to the previously used calculations based on the improved Weizsaker-Williams approximation, which turn out to be significant. We compare our cross sections values with the results from other calculations and find a good agreement between them. The possibility of future measurements with high-energy electron beams and the sensitivity to $A^{\prime }$ are briefly discussed.

    hep-phPLB(2018)·82 citations
17. 17*

    NLO QCD Predictions for $Wb\bar{b}$ Production in Association with up to Three Light Jets at the LHC

    F. R. Anger🇩🇪 · F. Febres Cordero🇩🇪 · H. Ita🇩🇪 · V. Sotnikov🇩🇪

    In this article we present the next-to-leading order QCD predictions for $Wb\bar{b}+n$-jet ($n=0,1,2,3$) production at the Large Hadron Collider with $\sqrt{s}=13$ TeV. We work in the four-flavor number scheme with a non-vanishing bottom-quark mass and include all subprocesses at leading electroweak order as well as all heavy-fermion-loop effects. We show the impact of QCD corrections for total as well as differential cross sections and make an assessment of theoretical uncertainties of $Wb\bar{b}$ production viewed as an irreducible background to $H(\to b\bar{b})W$ studies. For the calculations we have employed an upgraded version of the BlackHat library which can handle massive fermions in combination with SHERPA. Our results can be explored through publicly available $n$-tuple sets.

    hep-phhep-exPRD(2018)·30 citations
18. 18*

    Radiative Seesaw Model and DAMPE Excess from Leptophilic Gauge Symmetry

    Zhi-Long Han🇨🇳 · Weijian Wang🇨🇳 · Ran Ding🇨🇳

    In the light of the $e^{+}+e^{-}$ excess observed by DAMPE experiment, we propose an anomaly-free radiative seesaw model with an alternative leptophilic $U(1{)}_X$ gauge symmetry. In the model, only right-handed leptons are charged under $U(1{)}_X$ symmetry. The tiny Dirac neutrino masses are generated at one-loop level and charged leptons acquire masses though the type-I seesaw-like mechanism with heavy intermediate fermions. In order to cancel the anomaly, irrational $U(1{)}_X$ charge numbers are assigned to some new particles. After the spontaneous breaking of $U(1{)}_X$ symmetry, the dark $Z_2$ symmetry could appear as a residual symmetry such that the stability of inert particles with irrational charge numbers are guaranteed, naturally leading to stable DM candidates. We show that the Dirac fermion DM contained in the model can explain the DAMPE excess. Meanwhile, experimental constraints from DM relic density, direct detection, LEP and anomalous magnetic moments are satisfied.

    hep-phEPJC(2018)·22 citations
19. 19*

    Numerical evaluation of two-loop integrals with pySecDec

    S. Borowka🇨🇭 · G. Heinrich🇩🇪 · S. Jahn🇩🇪 · S.P. Jones🇩🇪 · M. Kerner🇩🇪 · J. Schlenk🇬🇧

    We describe the program pySecDec, which factorises endpoint singularities from multi-dimensional parameter integrals and can serve to calculate integrals occurring in higher order perturbative calculations numerically. We focus on the new features and on frequently asked questions about the usage of the program.

    hep-phActa Phys.Polon.Supp.(2018)·6 citations
20. 20*

    Fragmentation Uncertainties in Hadronic Observables for Top-quark Mass Measurements

    Gennaro Corcella🇮🇹 · Roberto Franceschini🇮🇹 · Doojin Kim🇨🇭

    We study the Monte Carlo uncertainties due to modeling of hadronization and showering in the extraction of the top-quark mass from observables that use exclusive hadronic final states in top decays, such as $t\to \text{anything+J/}\psi$ or $t\to \text{anything}+(B\to \text{charged tracks})$, where $B$ is a $B$-hadron. To this end, we investigate the sensitivity of the top-quark mass, determined by means of a few observables already proposed in the literature as well as some new proposals, to the relevant parameters of event generators, such as HERWIG 6 and PYTHIA 8. We find that constraining those parameters at $\mathcal{O}(1\%-10\%)$ is required to avoid a Monte Carlo uncertainty on $m_t$ greater than 500 MeV. For the sake of achieving the needed accuracy on such parameters, we examine the sensitivity of the top-quark mass measured from spectral features, such as peaks, endpoints and distributions of $E_B$, $m_{B\ell }$, and some $m_{T2}$-like variables. We find that restricting oneself to regions sufficiently close to the endpoints enables one to substantially decrease the dependence on the Monte Carlo parameters, but at the price of inflating significantly the statistical uncertainties. To ameliorate this situation we study how well the data on top-quark production and decay at the LHC can be utilized to constrain the showering and hadronization variables. We find that a global exploration of several calibration observables, sensitive to the Monte Carlo parameters but very mildly to $m_t$, can offer useful constraints on the parameters, as long as such quantities are measured with a 1% precision.

    hep-phhep-exNPB(2018)·34 citations
21. 21*

    Bottom-quark Forward-Backward Asymmetry, Dark Matter and the LHC

    Da Liu🇺🇸 · Jia Liu🇺🇸 · Carlos E.M. Wagner🇺🇸 · Xiao-Ping Wang🇺🇸

    The LEP experiment at CERN provided accurate measurements of the $Z$ neutral gauge boson properties. Although all measurements agree well with the SM predictions, the forward backward asymmetry of the bottom-quark remains almost 3$\sigma$ away from the SM value. We proposed that this anomaly may be explained by the existence of a new $U(1{)}_D$ gauge boson, which couples with opposite charges to the right-handed components of the bottom and charm quarks. Cancellation of gauge anomalies demands the presence of a vector-like singlet charged lepton as well as a neutral Dirac (or Majorana) particle that provides a Dark Matter candidate. Constraints from precision measurements imply that the mass of the new gauge boson should be around $115$~GeV. We discuss the experimental constraints on this scenario, including the existence of a di-jet resonance excess at an invariant mass similar to the mass of this new gauge boson, observed in boosted topologies at the CMS experiment.

    hep-phPRD(2018)·19 citations
22. 22*

    A Flavorful Factoring of the Strong CP Problem

    Prateek Agrawal🇺🇸 · Kiel Howe🇺🇸

    Motivated by the intimate connection between the strong CP problem and the flavor structure of the Standard Model, we present a flavor model that revives and extends the classic $m_u=0$ solution to the strong CP problem. QCD is embedded into a $SU(3{)}_1\times SU(3{)}_2\times SU(3{)}_3$ gauge group, with each generation of quarks charged under the respective $SU(3)$. The non-zero value of the up-quark Yukawa coupling (along with the strange quark and bottom-quark Yukawas) is generated by contributions from small instantons at a new scale $M\gg {\Lambda }_{QCD}$. The Higgsing of $SU(3{)}^3\to SU(3{)}_c$ allows dimension-5 operators that generate the Standard Model flavor structure and can be completed in a simple renormalizable theory. The smallness of the third generation mixing angles can naturally emerge in this picture, and is connected to the smallness of threshold corrections to $\bar{\theta }$. Remarkably, $\bar{\theta }$ is essentially fixed by the measured quark masses and mixings, and is estimated to be close to the current experimental bound and well within reach of the next generation of neutron and proton EDM experiments.

    hep-phJHEP(2018)·78 citations
23. 23*

    Quasi-fixed points from scalar sequestering and the little hierarchy problem in supersymmetry

    Stephen P. Martin🇺🇸

    In supersymmetric models with scalar sequestering, superconformal strong dynamics in the hidden sector suppresses the low-energy couplings of mass dimension two, compared to the squares of the dimension one parameters. Taking into account restrictions on the anomalous dimensions in superconformal theories, I point out that the interplay between the hidden and visible sector renormalizations gives rise to quasi-fixed point running for the supersymmetric Standard Model squared mass parameters, rather than driving them to 0. The extent to which this dynamics can ameliorate the little hierarchy problem in supersymmetry is studied. Models of this type in which the gaugino masses do not unify are arguably more natural, and are certainly more likely to be accessible, eventually, to the Large Hadron Collider.

    hep-phPRD(2018)·6 citations
24. 24*

    Orbifold family unification using vectorlike representation on six dimensions

    Yuhei Goto🇯🇵 · Yoshiharu Kawamura🇯🇵

    In orbifold family unification on the basis of $SU(N)$ gauge theory on the six-dimensional space-time $M^4\times T^2/Z_m$ ($m=2,3,4,6$), enormous numbers of models with three families of the standard model matter multiplets are derived from a massless Dirac fermion with a vectorlike representation $[N,3]+[N,N-3]$ of $SU(N)$ ($N=8,9$). They contain models with three or more than three neutrino singlets and without any non-Abelian continuous flavor gauge symmetries. The relationship between flavor numbers from a fermion with $[N,N-k]$ and those from a fermion with $[N,k]$ are studied from the viewpoint of charge conjugation.

    hep-phhep-thPRD(2018)·8 citations
25. 25*

    Photon-photon scattering at the high-intensity frontier

    Holger Gies🇩🇪 · Felix Karbstein🇩🇪 · Christian Kohlfürst🇩🇪 · Nico Seegert🇩🇪

    The tremendous progress in high-intensity laser technology and the establishment of dedicated high-field laboratories in recent years have paved the way towards a first observation of quantum vacuum nonlinearities at the high-intensity frontier. We advocate a particularly prospective scenario, where three synchronized high-intensity laser pulses are brought into collision, giving rise to signal photons, whose frequency and propagation direction differ from the driving laser pulses, thus providing various means to achieve an excellent signal to background separation. Based on the theoretical concept of vacuum emission, we employ an efficient numerical algorithm which allows us to model the collision of focused high-intensity laser pulses in unprecedented detail. We provide accurate predictions for the numbers of signal photons accessible in experiment. Our study paves the way for a first verification of quantum vacuum nonlinearity in a well-controlled laboratory experiment at one of the many high-intensity laser facilities currently coming online.

    hep-phhep-thphysics.opticsphysics.plasm-ph+1PRD(2018)·63 citations
26. 26*

    The three-pion decays of the $a_1(1260)$

    Xu Zhang🇨🇳 · Ju-Jun Xie🇨🇳

    We investigate the decay of $a_1^{+}(1260)\to {\pi }^{+}{\pi }^{+}{\pi }^{-}$ with the assumption that the $a_1(1260)$ is dynamically generated from the coupled channel $\rho \pi$ and $\bar{K}{K}^{\ast }$ interactions. In addition to the tree level diagrams that proceed via $a_1^{+}(1260)\to {\rho }^0{\pi }^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}$, we take into account also the final state interactions of $\pi \pi \to \pi \pi$ and $K\bar{K}\to \pi \pi$. We calculate the invariant ${\pi }^{+}{\pi }^{-}$ mass distribution and also the total decay width of $a_1^{+}(1260)\to {\pi }^{+}{\pi }^{+}{\pi }^{-}$ as a function of the mass of $a_1(1260)$. The calculated total decay width of $a_1(1260)$ is significantly different from other model calculations and tied to the dynamical nature of the $a_1(1260)$ resonance. The future experimental observations could test of model calculations and would provide vary valuable information on the relevance of the $\rho \pi$ component in the $a_1(1260)$ wave function.

    ↳ nucl-thhep-phnucl-exCommun.Theor.Phys.(2018)·12 citations
27. 27*

    Onset of $\eta$ nuclear binding

    Nir Barnea🇮🇱 · Betzalel Bazak🇮🇱 · Eliahu Friedman🇮🇱 · Avraham Gal🇮🇱 · Aleš Cieplý🇨🇿 · Jiří Mareš🇨🇿 · Martin Schäfer🇨🇿

    Recent studies of $\eta$ nuclear quasibound states by the Jerusalem-Prague Collaboration are reviewed, focusing on stochastic variational method self consistent calculations of $\eta$ few-nucleon systems. These calculations suggest that a minimum value Re$a_{\eta N}\approx 1$ fm (0.7 fm) is needed to bind $\eta {}^3$He ($\eta {}^4$He).

    ↳ nucl-thhep-phnucl-exEPJ Web Conf.(2018)·2 citations
28. 28*

    Cosmic Neutrinos

    Ofelia Pisanti🇮🇹

    Neutrinos are key astronomical messengers, because they are undeflected by magnetic field and unattenuated by electromagnetic interaction. After the first detection of extraterrestrial neutrinos in the TeV-PeV region by Neutrino Telescopes we are entering a new epoch where neutrino astronomy becomes possible. In this paper I briefly review the main issues concerning cosmological neutrinos and their experimental observation.

    ↳ astro-ph.COhep-phPoS(2017)·1 citation
29. 29*

    New experimental limits on neutron - mirror neutron oscillations in the presence of mirror magnetic field

    Z. Berezhiani🇮🇹 · R. Biondi🇮🇹 · P. Geltenbort🇫🇷 · I. A. Krasnoshchekova🇷🇺 · V. E. Varlamov🇷🇺 · A. V. Vassiljev🇷🇺 · O. M. Zherebtsov🇷🇺

    Present probes do not exclude that the neutron ($n$) oscillation into mirror neutron ($n^{\prime }$), a sterile state exactly degenerate in mass with the neutron, can be a very fast process, in fact faster than the neutron decay itself. This process is sensitive to the magnetic field. Namely, if the mirror magnetic field ${\vec{B}}^{\prime }$ exists at the Earth, $n-n^{\prime }$ oscillation probability can be suppressed or resonantly amplified by the applied magnetic field $\vec{B}$, depending on its strength and on the angle $\beta$ between $\vec{B}$ and ${\vec{B}}^{\prime }$. We present the results of ultra-cold neutron storage measurements aiming to check the anomalies observed in previous experiments which could be a signal for $n-n^{\prime }$ oscillation in the presence of mirror magnetic field $B^{\prime }\sim 0.1$~G. Analyzing the experimental data on neutron loses, we obtain a new lower limit on $n-n^{\prime }$ oscillation time ${\tau }_{n{n}^{\prime }}>17$ s (95 % C.L.) for any $B^{\prime }$ between 0.08 and 0.17 G, and ${\tau }_{n{n}^{\prime }}/\sqrt{\cos \beta }>27$s (95 % C.L.) for any $B^{\prime }$ in the interval ($0.06÷0.25$) G.

    ↳ hep-exhep-phEPJC(2018)·64 citations
30. 30*

    ${\Lambda }_c\to N$ form factors from lattice QCD and phenomenology of ${\Lambda }_c\to n{\ell }^{+}{\nu }_{\ell }$ and ${\Lambda }_c\to p{\mu }^{+}{\mu }^{-}$ decays

    Stefan Meinel🇺🇸

    A lattice QCD determination of the ${\Lambda }_c\to N$ vector, axial vector, and tensor form factors is reported. The calculation was performed with $2+1$ flavors of domain wall fermions at lattice spacings of $a\approx 0.11\mathrm{fm},0.085\mathrm{fm}$ and pion masses in the range $230\mathrm{MeV}\lesssim m_{\pi }\lesssim 350$ MeV. The form factors are extrapolated to the continuum limit and the physical pion mass using modified $z$ expansions. The rates of the charged-current decays ${\Lambda }_c\to n{e}^{+}{\nu }_e$ and ${\Lambda }_c\to n{\mu }^{+}{\nu }_{\mu }$ are predicted to be $\left(0.405\pm 0.016_{\mathrm{stat}}\pm 0.020_{\mathrm{syst}}\right)|V_{cd}{|}^2{\mathrm{ps}}^{-1}$ and $\left(0.396\pm 0.016_{\mathrm{stat}}\pm 0.020_{\mathrm{syst}}\right)|V_{cd}{|}^2{\mathrm{ps}}^{-1}$, respectively. The phenomenology of the rare charm decay ${\Lambda }_c\to p{\mu }^{+}{\mu }^{-}$ is also studied. The differential branching fraction, the fraction of longitudinally polarized dimuons, and the forward-backward asymmetry are calculated in the Standard Model and in an illustrative new-physics scenario.

    ↳ hep-lathep-exhep-phPRD(2018)·95 citations
31. 31*

    Multi moment cancellation of participant fluctuations

    Viktor Begun🇵🇱 · Maja Mackowiak-Pawlowska🇵🇱

    We summarize the new method for the correction of participant fluctuations in high energy nucleus-nucleus collisions. It allows to estimate a fluctuation baseline in comparison to a useful signal. In particular cases of a weak signal compared to baseline, it allows to cancel the baseline contribution from participants.

    ↳ nucl-thhep-exhep-phnucl-exPoS(2018)·1 citation

* 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.