Mon·Sep 21, 2015Monday·September 21, 2015

1. 01*

   Implications of the Diboson Excess for Neutrinoless Double Beta Decay and Lepton Flavor Violation in TeV Scale Left Right Symmetric Model

   Ram Lal Awasthi🇮🇳 · P. S. Bhupal Dev🇬🇧 · Manimala Mitra🇮🇳

   Inspired by the recent diboson excess observed at the LHC and possible interpretation within a TeV-scale Left-Right symmetric framework, we explore its implications for low-energy experiments searching for lepton number and flavor violation. Assuming a simple Type-II seesaw mechanism for neutrino masses, we show that for the right-handed (RH) gauge boson mass and coupling values required to explain the LHC anomalies, the RH contribution to the lepton number violating process of neutrinoless double beta decay ($0\nu \beta \beta$) is already constrained by current experiments for relatively low-mass (MeV-GeV) RH neutrinos. The future ton-scale $0\nu \beta \beta$ experiments could probe most of the remaining parameter space, irrespective of the neutrino mass hierarchy and uncertainties in the oscillation parameters and nuclear matrix elements. On the other hand, the RH contribution to the lepton flavor violating process of $\mu \to e\gamma$ is constrained for relatively heavier (TeV) RH neutrinos, thus providing a complementary probe of the model. Finally, a measurement of the absolute light neutrino mass scale from future precision cosmology could make this scenario completely testable.

   hep-phastro-ph.COhep-exPRD(2016)·58 citations
2. 02*

   Muon Anomalous Magnetic Moment in SUSY B-L Model with Inverse Seesaw

   Shaaban Khalil🇪🇬 · Cem Salih Un🇹🇷

   Motivated by the tension between the Higgs mass and muon g-2 in minimal supersymmetric standard model (MSSM), we analyze the muon g-2 in supersymmertic B-L extension of the standard model (BLSSM) with inverse seesaw mechanism. In this model, the Higgs mass receives extra important radiative corrections proportional to large neutrino Yukawa coupling. We point out that muon g-2 also gets significant contribution, due to the constructive interferences of light neutralino effects. The light neutralinos are typically the MSSM Bino like and the supersymmetric partner of U(1)_B-L gauge boson (B'-ino). We show that with universal soft supersymmetry breaking terms, the muon g-2 resides within 2 sigma of the measured value, namely ~17 x 10^-10, with Higgs mass equal to 125 GeV .

   hep-phPLB(2016)·35 citations
3. 03*

   Semiclassical Approach to Heterogeneous Vacuum Decay

   Benjamin Grinstein🇺🇸 · Christopher W. Murphy🇮🇹

   We derive the decay rate of an unstable phase of a quantum field theory in the presence of an impurity in the thin-wall approximation. This derivation is based on the how the impurity changes the (flat spacetime) geometry relative to case of pure false vacuum. Two examples are given that show how to estimate some of the additional parameters that enter into this heterogeneous decay rate. This formalism is then applied to the Higgs vacuum of the Standard Model (SM), where baryonic matter acts as an impurity in the electroweak Higgs vacuum. We find that the probability for heterogeneous vacuum decay to occur is suppressed with respect to the homogeneous case. That is to say, the conclusions drawn from the homogeneous case are not modified by the inclusion of baryonic matter in the calculation. On the other hand, we show that Beyond the Standard Model physics with a characteristic scale comparable to the scale that governs the homogeneous decay rate in the SM, can in principle lead to an enhanced decay rate.

   hep-phhep-thJHEP(2015)·18 citations
4. 04*

   General squark flavour mixing: constraints, phenomenology and benchmarks

   Karen De Causmaecker🇧🇪 · Benjamin Fuks🇫🇷 · Björn Herrmann🇫🇷 · Farvah Mahmoudi🇨🇭 · Ben O'Leary🇩🇪 · Werner Porod🇩🇪 · Sezen Sekmen🇰🇷 · Nadja Strobbe🇺🇸

   We present an extensive study of non-minimal flavour violation in the squark sector in the framework of the Minimal Supersymmetric Standard Model. We investigate the effects of multiple non-vanishing flavour-violating elements in the squark mass matrices by means of a Markov Chain Monte Carlo scanning technique and identify parameter combinations that are favoured by both current data and theoretical constraints. We then detail the resulting distributions of the flavour-conserving and flavour-violating model parameters. Based on this analysis, we propose a set of benchmark scenarios relevant for future studies of non-minimal flavour violation in the Minimal Supersymmetric Standard Model.

   hep-phhep-exJHEP(2015)·31 citations
5. 05*

   QCD Corrections to Pair Production of Type III Seesaw Leptons at Hadron Colliders

   Richard Ruiz🇬🇧

   If kinematically accessible, hadron collider experiments provide an ideal laboratory for the direct production of heavy lepton partners in Seesaw models. In the context of the Type III Seesaw Mechanism, the $\mathcal{O}({\alpha }_s)$ rate and shape corrections are presented for the pair production of hypothetical, heavy $SU(2{)}_L$ triplet leptons in $pp$ collisions at $\sqrt{s}=$ 13, 14, and 100 TeV. The next-to-leading order (NLO) $K$-factors span, approximately, $K^{NLO}=1.1-1.4$ for both charged current and neutral current processes over a triplet mass range $m_T=100\text{GeV}-2\text{TeV}$. Total production cross sections exhibit a ${}_{-6\%}^{+5\%}$ scale dependence at 14 TeV and $\pm 1\%$ at 100 TeV. The NLO differential $K$-factors for heavy lepton kinematics are largely flat, suggesting that naïve scaling by the total $K^{NLO}$ is reasonably justified. The resummed transverse momentum distribution of the dilepton system is presented at leading logarithmic (LL) accuracy. The effects of resummation are large in TeV-scale dilepton systems. Discovery potential to heavy lepton pairs at 14 and 100 TeV is briefly explored: At the High-Luminosity LHC, we estimate a $4.8-6.3\sigma$ discovery potential maximally for $m_T=1.5-1.6\text{TeV}$ after 3000 fb${}^{-1}$. With 300 (3000) fb${}^{-1}$, there is $2\sigma$ sensitivity up to $m_T=1.3-1.4\text{TeV}(1.7-1.8\text{TeV})$ in the individual channels. At 100 TeV and with 10 fb${}^{-1}$, a $5\sigma$ discovery can be achieved for $m_T=1.4-1.6\text{TeV}$. Due to the factorization properties of Drell-Yan-type systems, the fixed order and resummed calculations reduce to convolutions over tree-level quantities.

   hep-phhep-exJHEP(2015)·64 citations
6. 06*

   Linear inflation from quartic potential

   Kristjan Kannike🇪🇪 · Antonio Racioppi🇪🇪 · Martti Raidal🇪🇪

   We show that if the inflaton has a non-minimal coupling to gravity and the Planck scale is dynamically generated, the results of Coleman-Weinberg inflation are confined in between two attractor solutions: quadratic inflation, which is ruled out by the recent measurements, and linear inflation which, instead, is in the experimental allowed region. The minimal scenario has only one free parameter -- the inflaton's non-minimal coupling to gravity -- that determines all physical parameters such as the tensor-to-scalar ratio and the reheating temperature of the Universe. Should the more precise future measurements of inflationary parameters point towards linear inflation, further interest in scale-invariant scenarios would be motivated.

   hep-phastro-ph.COgr-qchep-thJHEP(2016)·78 citations
7. 07*

   Dileptons and Chiral Symmetry Restoration

   P. M. Hohler🇺🇸 · R. Rapp🇺🇸

   We report on recent work relating the medium effects observed in dilepton spectra in heavy-ion collisions to potential signals of chiral symmetry restoration. The key connection remains the approach to spectral function degeneracy between the vector-isovector channel with its chiral partner, the axialvector-isovector channel. Several approaches are discussed to elaborate this connection, namely QCD and Weinberg sum rules with input for chiral order parameters from lattice QCD, and chiral hadronic theory to directly evaluate the medium effects of the axialvector channel and the pertinent pion decay constant as function of temperature. A pattern emerges where the chiral mass splitting between rho and a_1 burns off and is accompanied by a strong broadening of the spectral distributions.

   hep-phnucl-thNucl.Part.Phys.Proc.(2016)·5 citations
8. 08*

   Flavor violating signatures of neutral Higgs bosons at the LHeC

   J. Hernandez-Sanchez🇲🇽 · S. P. Das🇲🇽 · S. Moretti🇬🇧 · A. Rosado🇲🇽 · R. Xoxocotzi🇲🇽

   We analyze the prospect for observing the lightest and heaviest CP-even neutral Higgs bosons ($\varphi =h,H$) in their decays to flavor violating $b\bar{s}$ (with charge conjugate) final states at the future Large Hadron electron Collider (LHeC), in the framework of the Two Higgs Doublet Model type III (2HDM-III) assuming a four-zero texture in the Yukawa matrices and a general Higgs potential. We consider the charge current production processes $e^{-}p\to {\nu }_e\varphi q_f$ ($\varphi =h,H$), with the flavor violating decays of the Higgs bosons. We consider scenarios of the model which are consistent with current experimental data from flavor and Higgs physics. We also consider the most relevant Standard Model (SM) backgrounds. We find that the lightest (SM-like) CP-even Higgs boson $h$ and the heaviest one $H$ (with mass up to 150 GeV) would have 1--2 $\Sigma$ and 1 $\Sigma$ significances, respectively, with 100 fb${}^{-1}$ of data. At the end of the LHeC running, the significances would be increased by ten times and the detection of both Higgs bosons ($h,H$) would be guaranteed.

   hep-phhep-exPoS(2015)·4 citations
9. 09*

   Prompt photon production in double-Pomeron-exchange events at the LHC

   A.K. Kohara🇧🇷 · C. Marquet🇫🇷

   Within the resolved Pomeron model of hard diffractive scattering, we compute prompt photon production in double-Pomeron-exchange events in proton-proton collisions. Using specific kinematical constraints chosen according to the acceptances of the forward proton detectors of experiments at the Large Hadron Collider, we provide estimates for inclusive and isolated photon production. This is done using the JetPhox program. We find that next-to-leading order corrections to the hard process are important and must be included in order to correctly constrain the quark and gluon content of the Pomeron from such processes at the LHC.

   hep-phPLB(2016)·11 citations
10. 10*

    Asymmetric dark matter and effective number of neutrinos

    Teruyuki Kitabayashi🇯🇵 · Yoshihiro Kurosawa🇯🇵

    We study the effect of the MeV-scale asymmetric dark matter annihilation on the effective number of neutrinos $N_{\mathrm{eff}}$ at the epoch of the big bang nucleosynthesis. If the asymmetric dark matter $\chi$ couples more strongly to the neutrinos $\nu$ than to the photons $\gamma$ and electrons $e^{-}$, ${\Gamma }_{\chi \gamma ,\chi e}\ll {\Gamma }_{\chi \nu }$, or ${\Gamma }_{\chi \gamma ,\chi e}\gg {\Gamma }_{\chi \nu }$, the lower mass limit on the asymmetric dark matter is about $18$ MeV for $N_{\mathrm{eff}}\simeq 3.0$.

    hep-phPRD(2016)·5 citations
11. 11*

    Charmful two-body anti-triplet $b$-baryon decays

    Y.K. Hsiao🇨🇳 · P.Y. Lin🇹🇼 · C.C. Lih🇹🇼 · C.Q. Geng🇨🇳

    We study the charmful decays of the two-body ${\mathcal{B}}_b\to {\mathcal{B}}_n{M}_c$ decays, where ${\mathcal{B}}_b$ represents the anti-triplet of $({\Lambda }_b,{\Xi }_b^0,{\Xi }_b^{-})$, ${\mathcal{B}}_n$ stands for the baryon octet and $M_c$ denotes as the charmed meson of $D_{(s)}^{(\ast )}$, ${\eta }_c$ and $J/\psi$. Explicitly, we predict that $\mathcal{B}({\Lambda }_b\to D_s^{-}p)=(1.8\pm 0.3)\times 10^{-5}$, which is within the measured upper bound of $\mathcal{B}({\Lambda }_b\to D_s^{-}p)<4.8(5.3)\times 10^{-4}$ at 90\%\,(95\%) C.L., and reproduce $\mathcal{B}({\Lambda }_b\to J/\psi \Lambda )=(3.3\pm 2.0)\times 10^{-4}$ and $\mathcal{B}({\Xi }_b^{-}\to J/\psi {\Xi }^{-})=(5.1\pm 3.2)\times 10^{-4}$ in agreement with the data. Moreover, we find that $\mathcal{B}({\Lambda }_b\to \Lambda {\eta }_c)=(1.5\pm 0.9)\times 10^{-4}$, $\mathcal{B}({\Xi }_b^{-}\to {\Xi }^{-}{\eta }_c)=(2.4\pm 1.5)\times 10^{-4}$ and $\mathcal{B}({\Xi }_b^0\to {\Xi }^0{\eta }_c,{\Xi }^{0}J/\psi )=(2.3\pm 1.4,4.9\pm 3.0)\times 10^{-4}$, which are accessible to the experiments at the LHCb.

    hep-phhep-exPRD(2015)·25 citations
12. 12*

    One-Loop Right-Handed Neutrino Threshold Corrections for Two-Loop Running in Supersymmetric Type I Seesaw Models

    Stefan Antusch🇨🇭 · Eros Cazzato🇨🇭

    The renormalization group (RG) running of the neutrino mass operator is required for comparing the predictions of neutrino models at high energy with the experimental data at low energies. In the type I seesaw scenario with n_G right-handed neutrinos, the RG running is also performed in the effective theories above and between the thresholds given by the masses of the right-handed neutrinos. At these thresholds, the effective theories are matched. When calculating the two-loop RG running, the matching has to be performed at the one-loop level. In this work, we calculate the one-loop matching formulae in the MSSM extended by n_G right-handed neutrinos using supergraph techniques. Moreover we present a general formula for one-loop matching of superpotential operators which can readily be applied to any supersymmetric theory where chiral superfields are integrated out.

    hep-phJHEP(2015)·6 citations
13. 13*

    LHC signatures of a Z' mediator between dark matter and the SU(3) sector

    Otilia Ducu🇷🇴 · Lucien Heurtier🇫🇷 · Julien Maurer🇷🇴

    In this paper, we study the experimental signatures of a gluophilic $Z^{\prime }$ at the LHC, in particular through the analysis of three jets or four tops events. The $Z^{\prime }$ couples to gluons through dimension six operators and the parameter space is constrained with experimental searches released at 7 and 8 $\mathrm{TeV}$ by CMS along these two different channels. Existing constraints coming from the study of dark matter where the $Z^{\prime }$ represents a possible mediator between the latter and the Standard Model are also included for comparison. Prospects at $\sqrt{s}=13$ TeV allow us to evaluate for which values of the parameter space a gluophilic $Z^{\prime }$ could be discovered during the next run of the LHC. In particular, we show that the analysis of the three jets invariant mass could provide a clear signal ($>5\sigma$) for masses of the $Z^{\prime }$ above 300 $\mathrm{GeV}$. Four tops events bring in addition further discovery potential for heavy $Z^{\prime }$ (above $\sim 2\mathrm{TeV}$). A combination of both signals in four top channels and three jets analyses during the next run of the LHC could thus provide a clear signal of the presence of a heavy gluophilic $Z^{\prime }$.

    hep-phhep-exJHEP(2016)·30 citations
14. 14*

    Reference calculations for subthreshold $\Xi$ production

    Boris Tomasik🇸🇰 · Evgeni E Kolomeitsev🇸🇰

    We present a minimal statistical model designed for the description of rare-hadron multiplicities in nucleus-nucleus collisions at energies below the threshold of the particle production in binary elementary collisions. Differences to more conventional canonical statistical model are explained. The minimal statistical model is applied to the description of multiplicity ratios involving $\Xi$ hyperons, which are measured by the HADES collaboration at GSI-SIS. It is argued that the HADES data cannot be reproduced by the model based on the statistical equilibrium and the strangeness conservation. The data remain underpredicted even when in-medium potentials acting on hadrons are taken into account. This hints to non-equilibrium production of the $\Xi$ hyperons and their continuous freeze-out.

    ↳ nucl-thhep-phJ.Phys.Conf.Ser.(2016)·0 citations
15. 15*

    New Results from the Studies of the $N(1440)1/2^{+}$, $N(1520)3/2^{-}$, and $\Delta (1620)1/2^{-}$ Resonances in Exclusive $ep\to e^{\prime }{p}^{\prime }{\pi }^{+}{\pi }^{-}$ Electroproduction with the CLAS Detector

    V.I.Mokeev🇺🇸 · V.D.Burkert🇺🇸 · D.S.Carman🇺🇸 · L.Elouadrhiri🇺🇸 · G.V.Fedotov🇺🇸 · E.N.Golovatch🇷🇺 · R.W.Gothe🇺🇸 · K.Hicks🇺🇸 · B.S.Ishkhanov🇷🇺 · E.L.Isupov🇷🇺 · Iu.Skorodumina🇺🇸

    The transition helicity amplitudes from the proton ground state to the $N(1440)1/2^{+}$, $N(1520)3/2^{-}$, and $\Delta (1620)1/2^{-}$ resonances (${\gamma }_{v}p{N}^{\ast }$ electrocouplings) were determined from the analysis of nine independent one-fold differential ${\pi }^{+}{\pi }^{-}p$ electroproduction cross sections off a proton target, taken with CLAS at photon virtualities 0.5 GeV${}^2$ $<Q^2<$ 1.5 GeV${}^2$. The phenomenological reaction model employed for separation of the resonant and non-resonant contributions to this exclusive channel was further developed. The $N(1440)1/2^{+}$, $N(1520)3/2^{-}$, and $\Delta (1620)1/2^{-}$ electrocouplings were obtained from the resonant amplitudes of charged double-pion electroproduction off the proton in the aforementioned area of photon virtualities for the first time. Consistent results on ${\gamma }_{v}p{N}^{\ast }$ electrocouplings available from independent analyses of several $W$-intervals with different non-resonant contributions offer clear evidence for the reliable extraction of these fundamental quantities. These studies also improved the knowledge on hadronic branching ratios for the $N(1440)1/2^{+}$, $N(1520)3/2^{-}$, and $\Delta (1620)1/2^{-}$ decays to the $\pi \Delta$ and $\rho N$ final states. These new results provide a substantial impact on the QCD-based approaches that describe the $N^{\ast }$ structure and demonstrate the capability to explore fundamental ingredients of the non-perturbative strong interaction that are behind the excited nucleon state formation.

    ↳ nucl-exhep-phPRC(2016)·117 citations
16. 16*

    Scalar field correlator in de Sitter space at next-to-leading order in a 1/N expansion

    Florian Gautier🇩🇪 · Julien Serreau🇫🇷

    We study the dynamics of light quantum scalar fields in de Sitter space on superhorizon scales. We compute the self-energy of an O(N) symmetric theory at next-to-leading order in a 1/N expansion in the regime of superhorizon momenta, and we obtain an exact analytical solution of the corresponding Dyson-Schwinger equations for the two-point correlator. This amounts to resumming the infinite series of nonlocal self-energy insertions, which typically generate spurious infrared and/or secular divergences. The potentially large de Sitter logarithms resum into well-behaved power laws from which we extract the field strength and mass renormalization. The nonperturbative 1/N expansion allows us to discuss the case of vanishing and negative tree-level square mass, which both correspond to strongly coupled effective theories in the infrared.

    ↳ hep-thgr-qchep-phnucl-thPRD(2015)·63 citations
17. 17*

    Evaluation of the strength of electron-proton scattering data for determining the proton charge radius

    M. Horbatsch🇨🇦 · E.A. Hessels🇨🇦

    Precisely measured electron-proton elastic scattering cross sections [Phys. Rev. Lett. {\bf 105}, 242002 (2010)] are reanalyzed to evaluate their strength for determining the rms charge radius ($R_{\mathrm{E}}$) of the proton. More than half of the cross sections at lowest $Q^2$ are fit using two single-parameter form-factor models, with the first based on a dipole parametrization, and the second on a linear fit to a conformal-mapping variable. These low-$Q^2$ fits extrapolate the slope of the form factor to $Q^2$=0 and determine $R_{\mathrm{E}}$ values of approximately 0.84 and 0.89~fm, respectively. Fits spanning all $Q^2$, in which the single constants are replaced with cubic splines at larger $Q^2$, lead to similar results for $R_{\mathrm{E}}$. We conclude that the scattering data is consistent with $R_{\mathrm{E}}$ ranging from at least 0.84 to 0.89~fm, and therefore cannot resolve the discrepancy between determinations of $R_{\mathrm{E}}$ made using muonic and electronic hydrogen-atom spectroscopy.

    ↳ nucl-exhep-phphysics.atom-phPRC(2016)·52 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.