Mon·Feb 1, 2016Monday·February 1, 2016

1. 01*

   LHC Benchmark Scenarios for the Real Higgs Singlet Extension of the Standard Model

   Tania Robens🇩🇪 · Tim Stefaniak🇺🇸

   We present benchmark scenarios for searches for an additional Higgs state in the real Higgs singlet extension of the Standard Model in Run 2 of the LHC. The scenarios are selected such that they fulfill all relevant current theoretical and experimental constraints, but can potentially be discovered at the current LHC run. We take into account the results presented in earlier work and update the experimental constraints from relevant LHC Higgs searches and signal rate measurements. The benchmark scenarios are given separately for the low mass and high mass region, i.e. the mass range where the additional Higgs state is lighter or heavier than the discovered Higgs state at around 125 GeV. They have also been presented in the framework of the LHC Higgs Cross Section Working Group.

   hep-phhep-exEPJC(2016)·186 citations
2. 02*

   LHC signals of a BLSSM CP-even Higgs boson

   A. Hammad🇪🇬 · S. Khalil🇪🇬 · S. Moretti🇬🇧

   We study the scope of the Large Hadron Collider in accessing a neutral Higgs boson of the $B-L$ Supersymmetric Standard Model. After assessing the surviving parameter space configurations following the Run 1 data taking, we investigate the possibilities of detecting this object during Run 2. For the model configurations in which the mixing between such a state and the discovered Standard Model-like Higgs boson is non-negligible, there exist several channels enabling its discovery over a mass range spanning from $\approx 140$ to $\approx$ 500 GeV. For a lighter Higgs state, with mass of order 140 GeV, three channels are accessible: $\gamma \gamma$, $Z\gamma$ and $ZZ$, wherein the $Z$ boson decays leptonically. For a heavier Higgs state, with mass above 250 GeV (i.e., twice the mass of the Higgs state discovered in 2012), the hallmark signature is its decay in two such 125 GeV scalars, $h^{\prime }\to hh$, where $hh\to b\bar{b}\gamma \gamma$. In all such cases, significances above discovery can occur for already planned luminosities at the CERN machine.

   hep-phPRD(2016)·22 citations
3. 03*

   $\tau$ dipole moments via radiative leptonic $\tau$ decays

   S. Eidelman🇷🇺 · D. Epifanov🇯🇵 · M. Fael🇨🇭 · L. Mercolli🇺🇸 · M. Passera🇮🇹

   We propose a new method to probe the magnetic and electric dipole moments of the $\tau$ lepton using precise measurements of the differential rates of radiative leptonic $\tau$ decays at high-luminosity $B$ factories. Possible deviations of these moments from the Standard Model values are analyzed in an effective Lagrangian approach, thus providing model-independent results. Analytic expressions for the relevant non-standard contributions to the differential decay rates are presented. Earlier proposals to probe the $\tau$ dipole moments are examined. A detailed feasibility study of our method is performed in the conditions of the Belle and Belle II experiments at the KEKB and Super-KEKB colliders, respectively. This study shows that our approach, applied to the planned full set of Belle II data for radiative leptonic $\tau$ decays, has the potential to improve the present experimental bound on the $\tau$ anomalous magnetic moment. On the contrary, its foreseen sensitivity is not expected to lower the current experimental limit on the $\tau$ electric dipole moment.

   hep-phhep-exJHEP(2016)·73 citations
4. 04*

   Two-photon exchange corrections in elastic electron-proton scattering

   O. Tomalak🇩🇪

   We apply a subtracted dispersion relation (DR) formalism with the aim to improve predictions for the two-photon exchange (TPE) corrections to elastic electron-proton scattering observables at small momentum transfers. We study the formalism on the elastic TPE contribution in comparison with existing data for unpolarized cross sections. We extend the general formalism of TPE to elastic scattering with massive lepton and perform a numerical estimate of the muon-proton scattering at low momentum transfer in view of the upcoming muon-proton scattering experiment (MUSE). We study the influence of the double-virtual Compton scattering (VVCS) subtraction function on the unpolarized lepton-proton scattering cross-section. We show that the resulting TPE correction is negligible in the electron-proton scattering and smaller than planned uncertainties of the MUSE experiment for the subtraction functions evaluated in chiral perturbation theory.

   hep-phnucl-thPoS(2015)·0 citations
5. 05*

   Prospects for studying vacuum polarisation using dipole and synchrotron radiation

   Anton Ilderton🇸🇪 · Mattias Marklund🇸🇪

   The measurement of vacuum polarisation effects, in particular vacuum birefringence, using combined optical and x-ray laser pulses is now actively pursued. Here we briefly examine the feasibility of two alternative setups. The first utilises an alternative target, namely a converging dipole pulse, and the second uses an alternative probe, namely the synchrotron-like emission from highly energetic particles, themselves interacting with a laser pulse. The latter setup has been proposed for experiments at ELI-NP.

   hep-phphysics.opticsJ.Plasma Phys.(2016)·33 citations
6. 06*

   Coxeter groups and the PMNS matrix

   Pritibhajan Byakti🇮🇳 · Palash B. Pal🇮🇳

   We discuss the symmetries of the Lagrangian of the leptonic sector. We consider the case when this symmetry group is a Coxeter group. The number of elements of the PMNS matrix predicted by this group structure would depend on the number of generators of this group. We analyze finite Coxeter groups with 2 to 4 generators and even finite subgroups of infinite Coxeter groups with 4 generators and show which of them can give results that are consistent with experimental data.

   hep-phEPJC(2017)·4 citations
7. 07*

   Two scales in Bose-Einstein correlations

   V.A. Khoze🇬🇧 · A.D. Martin🇬🇧 · M.G. Ryskin🇬🇧 · V.A. Schegelsky🇷🇺

   We argue that the secondaries produced in high energy hadron collisions are emitted by small size sources distributed over a much larger area in impact parameter space occupied by the interaction amplitude. That is, Bose-Einstein correlation of two emitted identical particles should be described by a `two-radii' parametrization ansatz. We discuss the expected energy, charged multiplicity and transverse momentum of the pair (that is, $\sqrt{s},N_{\mathrm{ch}},k_t$) behaviour of both the small and large size components.

   hep-phEPJC(2016)·9 citations
8. 08*

   On the renormalization of operator products: the scalar gluonic case

   Max F. Zoller🇨🇭

   In this paper we study the renormalization of the product of two operators $O_1=-\frac{1}{4}{G}^{\mu \nu }{G}_{\mu \nu }$ in QCD. An insertion of two such operators $O_1(x)O_1(0)$ into a Greens function produces divergent contact terms for $x\to 0$. In the course of the computation of the operator product expansion (OPE) of the correlator of two such operators $i\int {\mathrm{d}}^{4}x{e}^{iqx}T\{O_1(x)O_1(0)\}$ to three-loop order we discovered that divergent contact terms remain not only in the leading Wilson coefficient $C_0$, which is just the VEV of the correlator, but also in the Wilson coefficient $C_1$ in front of $O_1$. As this correlator plays an important role for example in QCD sum rules a full understanding of its renormalization is desireable. This work explains how the divergences encountered in higher orders of an OPE of this correlator should be absorbed in counterterms and derives an additive renormalization constant for $C_1$ from first principles and to all orders in perturnbation theory. The method to derive the renormalization of this operator product is an extension of the ideas of a paper by Spiridonov and can be generalized to other cases.

   hep-phJHEP(2016)·16 citations
9. 09*

   Precise Predictions for the Higgs-Boson Masses in the NMSSM

   Peter Drechsel🇩🇪 · Leonardo Galeta🇪🇸 · Sven Heinemeyer🇪🇸 · Georg Weiglein🇩🇪

   The particle discovered in the Higgs boson searches at the LHC with a mass of about 125 GeV can be identified with one of the neutral Higgs bosons of the Next-to-Minimal Supersymmetric Standard Model (NMSSM). We calculate predictions for the Higgs-boson masses in the NMSSM using the Feynman-diagrammatic approach. The predictions are based on the full NMSSM one-loop corrections supplemented with the dominant and sub-dominant two-loop corrections within the Minimal Supersymmetric Standard Model (MSSM). These include contributions at $\mathcal{O}\left({\alpha }_t{\alpha }_s,{\alpha }_b{\alpha }_s,{\alpha }_t^2,{\alpha }_t{\alpha }_b\right)$, as well as a resummation of leading and subleading logarithms from the top/scalar top sector. Taking these corrections into account in the prediction for the mass of the Higgs boson in the NMSSM that is identified with the observed signal is crucial in order to reach a precision at a similar level as in the MSSM. The quality of the approximation made at the two-loop level is analysed on the basis of the full one-loop result, with a particular focus on the prediction for the Standard Model-like Higgs boson that is associated with the observed signal. The obtained results will be used as a basis for the extension of the code FeynHiggs to the NMSSM.

   hep-phEPJC(2017)·41 citations
10. 10*

    mr: a C++ library for the matching and running of the Standard Model parameters

    Bernd A. Kniehl🇩🇪 · Andrey F. Pikelner🇩🇪 · Oleg L. Veretin🇩🇪

    We present the C++ program library mr that allows us to reliably calculate the values of the running parameters in the Standard Model at high energy scales. The initial conditions are obtained by relating the running parameters in the $\overline{\mathrm{MS}}$ renormalization scheme to observables at lower energies with full two-loop precision. The evolution is then performed in accordance with the renormalization group equations with full three-loop precision. Pure QCD corrections to the matching and running are included through four loops. We also provide a Mathematica interface for this program library.

    hep-phhep-exhep-thComput.Phys.Commun.(2016)·51 citations
11. 11*

    Probing top quark neutral couplings in the Standard Model Effective Field Theory at NLO QCD

    Olga Bessidskaia Bylund🇸🇪 · Fabio Maltoni🇧🇪 · Ioannis Tsinikos🇧🇪 · Eleni Vryonidou🇧🇪 · Cen Zhang🇺🇸

    Top quark pair production in association with a $Z$-boson or a photon at the LHC directly probes neutral top-quark couplings. We present predictions for these two processes in the Standard Model (SM) Effective Field Theory (EFT) at next-to-leading (NLO) order in QCD. We include the full set of CP-even dimension-six operators that enter the top-quark interactions with the SM gauge bosons. For comparison, we also present predictions in the SMEFT for top loop-induced $HZ$ production at the LHC and for $t\bar{t}$ production at the ILC at NLO in QCD. Results for total cross sections and differential distributions are obtained and uncertainties coming from missing higher orders in the strong coupling and in the EFT expansions are discussed. NLO results matched to the parton shower are available, allowing for event generation to be directly employed in an experimental analyses. Our framework provides a solid basis for the interpretation of current and future measurements in the SMEFT, with improved accuracy and precision.

    hep-phJHEP(2016)·208 citations
12. 12*

    Conductivity bounds in probe brane models

    Tatsuhiko N. Ikeda🇺🇸 · Andrew Lucas🇺🇸 · Yuichiro Nakai🇺🇸

    We discuss upper and lower bounds on the electrical conductivity of finite temperature strongly coupled quantum field theories, holographically dual to probe brane models, within linear response. In a probe limit where disorder is introduced entirely through an inhomogeneous background charge density, we find simple lower and upper bounds on the electrical conductivity in arbitrary dimensions. In field theories in two spatial dimensions, we show that both bounds persist even when disorder is included in the bulk metric. We discuss the challenges with finding sharp lower bounds on conductivity in three or more spatial dimensions when the metric is inhomogeneous.

    ↳ hep-thcond-mat.stat-mechcond-mat.str-elhep-phJHEP(2016)·15 citations
13. 13*

    Parameterized Machine Learning for High-Energy Physics

    Pierre Baldi🇺🇸 · Kyle Cranmer🇺🇸 · Taylor Faucett🇺🇸 · Peter Sadowski🇺🇸 · Daniel Whiteson🇺🇸

    We investigate a new structure for machine learning classifiers applied to problems in high-energy physics by expanding the inputs to include not only measured features but also physics parameters. The physics parameters represent a smoothly varying learning task, and the resulting parameterized classifier can smoothly interpolate between them and replace sets of classifiers trained at individual values. This simplifies the training process and gives improved performance at intermediate values, even for complex problems requiring deep learning. Applications include tools parameterized in terms of theoretical model parameters, such as the mass of a particle, which allow for a single network to provide improved discrimination across a range of masses. This concept is simple to implement and allows for optimized interpolatable results.

    ↳ hep-excs.LGhep-phEPJC(2016)·309 citations
14. 14*

    Double Chooz and a History of Reactor Theta13 Experiments

    F. Suekane🇯🇵 · T.J.C. Bezerra (for the Double Chooz Collaboration)🇫🇷

    This is a contribution paper from the Double Chooz experiment to the special issue of NPB on neutrino oscillations. The physics and a history of the reactor theta13 experiments, as well as Double Chooz experiment and its neutrino oscillation analyses are reviewed.

    ↳ hep-exhep-phNPB(2016)·9 citations
15. 15*

    Lorentz Constraints on Massive Three-Point Amplitudes

    Eduardo Conde🇰🇷 · Andrea Marzolla🇧🇪

    Using the helicity-spinor language we explore the non-perturbative constraints that Lorentz symmetry imposes on three-point amplitudes where the asymptotic states can be massive. As it is well known, in the case of only massless states the three-point amplitude is fixed up to a coupling constant by these constraints plus some physical requirements. We find that a similar statement can be made when some of the particles have mass. We derive the generic functional form of the three-point amplitude by virtue of Lorentz symmetry, which displays several functional structures accompanied by arbitrary constants. These constants can be related to the coupling constants of the theory, but in an unambiguous fashion only in the case of one massive particle. Constraints on these constants are obtained by imposing that in the UV limit the massive amplitude matches the massless one. In particular, there is a certain Lorentz frame, which corresponds to projecting all the massive momenta along the same null momentum, where the three-point massive amplitude is fully fixed, and has a universal form.

    ↳ hep-thhep-phJHEP(2016)·80 citations
16. 16*

    Predictions for $\sqrt{s_{NN}}=5.02$ TeV Pb+Pb Collisions from a Multi-Phase Transport Model

    Guo-Liang Ma🇨🇳 · Zi-Wei Lin🇺🇸

    We present predictions from the string melting version of a multi-phase transport model on various observables in Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV. We use the same version of the model as an earlier study that reasonably reproduced dN/dy, $p_{\mathrm{T}}$-spectra and elliptic flow of charged pions and kaons at low-$p_{\mathrm{T}}$ for central and semi-central heavy ion collisions at 200 GeV and 2.76 TeV. While we compare with the already-available centrality dependence data on charged particle $dN/d\eta$ at mid-pseudorapidity in Pb+Pb collisions at 5.02 TeV, we make predictions on identified particle dN/dy, $p_{\mathrm{T}}$-spectra, azimuthal anisotropies $v_n(n=2,3,4)$, and factorization ratios $r_n({\eta }^a,{\eta }^b)(n=2,3)$ for longitudinal correlations.

    ↳ nucl-thhep-phnucl-exPRC(2016)·106 citations
17. 17*

    Geometric dark energy traversable wormholes constrained by astrophysical observations

    Deng Wang🇨🇳 · Xin-He Meng🇨🇳

    In this letter, we introduce the astrophysical observations into the wormhole research, which is not meant to general parameters constraints for the dark energy models, in order to understand more about in which stage of the universe evolutions wormholes may exist through the investigation of the evolution behavior of the cosmic equation of state parameter. As a concrete instance, we investigate the Ricci dark energy (RDE) traversable wormholes constrained by astrophysical data-sets. Particularly, we can discover from Fig. \ref{fig5} of the present work, when the effective equation of state parameter ${\omega }_X<-1$, namely, the Null Energy conditions (NEC) is violated clearly, the wormholes will appear (open). Subsequently, six specific solutions of static and spherically symmetric traversable wormhole supported by the RDE are obtained. Except for the case of constant redshift function, in which the solution is not only asymptotically flat but also traversable, the remaining five solutions are all not asymptotically flat, therefore, the exotic matter from the RDE fluids is spatially distributed in the vicinity of the throat. Furthermore, we analyze the physical characteristics and properties of the RDE traversable wormholes. It is worth noting that, through the astrophysical observations, we get constraints on the parameters of RDE model, explore the type of exotic RDE fluids in different stages of the universe changing, limit the number of available models for wormhole research, reduce the number of the wormholes corresponding to different parameters for RDE model and provide a more apparent picture for wormhole investigations from the new perspective of observational cosmology background

    ↳ gr-qcastro-ph.COhep-phhep-th+23 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.