Tue·Oct 6, 2015Tuesday·October 6, 2015

1. 01*

   Sterile neutrinos in the light of IceCube

   Manfred Lindner🇩🇪 · Werner Rodejohann🇩🇪 · Xun-Jie Xu🇩🇪

   We determine constraints on parameters of a single eV-scale light neutrino using IceCube-59 data. Particular emphasis is put on the question whether such an analysis can rule out sterile neutrino hints. While important complementary information is provided, the different dependence on the various sterile neutrino mixing angles makes it currently not possible to fully exclude short baseline appearance results or sterile neutrinos in general.

   hep-phastro-ph.HEhep-exJHEP(2016)·37 citations
2. 02*

   Analytical improvements to the Breit-Wigner isobar models

   Adam P. Szczepaniak🇺🇸

   We discuss the derivation and properties of the general representation of partial wave amplitudes in the context of improving the models currently used in analysis of three particle Dalitz distributions.

   hep-phhep-ex3 citations
3. 03*

   Natural Relaxation

   Luca Marzola🇪🇪 · Martti Raidal🇪🇪

   Motivated by natural inflation, we propose a relaxation mechanism consistent with inflationary cosmology that explains the hierarchy between the electroweak scale and Planck scale. This scenario is based on a selection mechanism that identifies the low scale dynamics as the one that is screened from UV physics. The scenario also predicts the near-criticality and metastability of the standard model vacuum state, explaining the Higgs boson mass observed at the LHC. Once Majorana right-handed neutrinos are introduced to provide a viable reheating channel, our framework yields a corresponding mass scale that allows for the seesaw mechanism as well as for standard thermal leptogenesis. We argue that considering singlet scalar dark matter extensions of the proposed scenario could solve the vacuum stability problem and discuss how the cosmological constant problem is possibly addressed.

   hep-phhep-thMod.Phys.Lett.A(2016)·31 citations
4. 04*

   Explaining the Fermi Galactic Centre Excess in the CMSSM

   Andrew J. Williams🇵🇱

   We present an analysis of the compatibility between the Galactic Centre Excess (GCE) and the Constrained MSSM (CMSSM). We perform a global fit to the relevant experimental data including the GCE taking into account the systematic uncertainties. We find that the CMSSM is able to account for the GCE and maintain agreement with the other experimental searches, providing the first example that the GCE can be explained in the framework of universal supersymmetry. We map out the region compatible at 2 sigma and comment on its phenomenology. We find that for the CMSSM to explain the GCE the solution must lie close to the existing limits from LUX, IceCube and the LHC. We show that this provides definite predictions for Run 2 of the LHC, Xenon-1T and future observation with IceCube. Thus there exists the exciting possibility that the CMSSM could be observed in four distinct experimental channels over the next few years, which would be a striking signature for universal supersymmetry.

   hep-phastro-ph.CO8 citations
5. 05*

   Leptogenesis scenarios for natural SUSY with mixed axion-higgsino dark matter

   Kyu Jung Bae🇺🇸 · Howard Baer🇺🇸 · Hasan Serce🇺🇸 · Yi-Fan Zhang🇨🇳

   Supersymmetric models with radiatively-driven electroweak naturalness require light higgsinos of mass ~ 100-300 GeV. Naturalness in the QCD sector is invoked via the Peccei-Quinn (PQ) axion leading to mixed axion-higgsino dark matter. The SUSY DFSZ axion model provides a solution to the SUSY mu problem and the Little Hierarchy \mu << m_{3/2} may emerge as a consequence of a mismatch between PQ and hidden sector mass scales. The traditional gravitino problem is now augmented by the axino and saxion problems, since these latter particles can also contribute to overproduction of WIMPs or dark radiation, or violation of BBN constraints. We compute regions of the T_R vs. m_{3/2} plane allowed by BBN, dark matter and dark radiation constraints for various PQ scale choices f_a. These regions are compared to the values needed for thermal leptogenesis, non-thermal leptogenesis, oscillating sneutrino leptogenesis and Affleck-Dine leptogenesis. The latter three are allowed in wide regions of parameter space for PQ scale f_a~ 10^{10}-10^{12} GeV which is also favored by naturalness: f_a~ \sqrt{\mu M_P/\lambda_\mu }\sim 10^{10}-10^{12} GeV. These f_a values correspond to axion masses somewhat above the projected ADMX search regions.

   hep-phastro-ph.COJCAP(2016)·23 citations
6. 06*

   Direct and indirect constraints on CP-violating Higgs-quark and Higgs-gluon interactions

   Y.-T. Chien🇺🇸 · V. Cirigliano🇺🇸 · W. Dekens🇳🇱 · J. de Vries🇩🇪 · E. Mereghetti🇺🇸

   We investigate direct and indirect constraints on the complete set of anomalous CP-violating Higgs couplings to quarks and gluons originating from dimension-6 operators, by studying their signatures at the LHC and in electric dipole moments (EDMs). We show that existing uncertainties in hadronic and nuclear matrix elements have a significant impact on the interpretation of EDM experiments, and we quantify the improvements needed to fully exploit the power of EDM searches. Currently, the best bounds on the anomalous CP-violating Higgs interactions come from a combination of EDM measurements and the data from LHC Run 1. We argue that Higgs production cross section and branching ratios measurements at the LHC Run 2 will not improve the constraints significantly. On the other hand, the bounds on the couplings scale roughly linearly with EDM limits, so that future theoretical and experimental EDM developments can have a major impact in pinning down interactions of the Higgs.

   hep-phhep-latnucl-exnucl-thJHEP(2016)·122 citations
7. 07*

   Non-perturbative QCD effects in forward scattering at LHC

   C.A.S. Bahia🇧🇷 · M. Broilo🇧🇷 · E.G.S. Luna🇧🇷

   We study infrared contributions to semihard parton-parton interactions by considering an effective charge whose finite infrared behavior is constrained by a dynamical mass scale. Using an eikonal QCD-based model in order to connect this semihard parton-level dynamics to the hadron-hadron scattering, we obtain predictions for the proton-proton ($pp$) and antiproton-proton ($\bar{p}p$) total cross sections, ${\sigma }_{tot}^{pp,\bar{p}p}$, and the ratios of the real to imaginary part of the forward scattering amplitude, ${\rho }^{pp,\bar{p}p}$. We discuss the theoretical aspects of this formalism and consider the phenomenological implications of a class of energy-dependent form factors in the high-energy behavior of the forward amplitude. We introduce integral dispersion relations specially tailored to relate the real and imaginary parts of eikonals with energy-dependent form factors. Our results, obtained using a group of updated sets of parton distribution functions (PDFs), are consistent with the recent data from the TOTEM, AUGER and Telescope Array experiments.

   hep-phhep-exPRD(2015)·22 citations
8. 08*

   Electroweak Vacuum Stability and the Seesaw Mechanism Revisited

   John Ng🇨🇦 · Alejandro de la Puente🇨🇦

   We study the electroweak vacuum stability in Type I seesaw models for 3 generations of neutrinos in scenarios where the right-handed neutrinos have explicit bare mass terms in the Lagrangian and where these are dynamically generated through the mechanism of spontaneous symmetry breaking. To best highlight the difference of the two cases we concentrate on the absolute stability of the scalar potential. We observe that for the first scenario, the scale at which the scalar potential becomes unstable is lower from that within the Standard Model. In addition the Yukawa couplings ${\mathbf{Y}}_{\nu }$ are constrained such that $\text{Tr}[{\mathbf{Y}}_{\nu }^{†}{\mathbf{Y}}_{\nu }]\lesssim 10^{-3}$. In the second scenario the electroweak stability can be improved in a large region of parameter space. However, we found that the scalar used to break the lepton number symmetry cannot be too light and have a large coupling to right-handed neutrinos in order for the seesaw mechanism to be a valid mechanism for neutrino mass generation. In this case we have $\text{Tr}[{\mathbf{Y}}_{\nu }^{†}{\mathbf{Y}}_{\nu }]\lesssim 0.01$.

   hep-phEPJC(2016)·24 citations
9. 09*

   Uncovering the Matter-Neutrino Resonance

   D. Vaananen🇺🇸 · G. C. McLaughlin🇺🇸

   Matter Neutrino Resonances (MNRs) can drastically modify neutrino flavor evolution in astrophysical environments and may significantly impact nucleosynthesis. Here we further investigate the underlying physics of MNR type flavor transitions. We provide generalized resonance conditions and make analytical predictions for the behavior of the system. We discuss the adiabatic evolution of these transitions, considering both Symmetric and Standard scenarios. Symmetric MNR transitions differ from Standard MNR transitions in that both neutrinos and antineutrinos can completely transform to other flavors simultaneously. We provide an example of the simplest system in which such transitions can occur with a neutrino and an antineutrino having a single energy and emission angle. We further apply linearized stability analysis to predict the location of self-induced nutation type (or bipolar) oscillations due to neutrino-neutrino interactions in the regions where MNR is ineffective. In all cases, we compare our analytical predictions to numerical calculations.

   hep-phastro-ph.HEnucl-thPRD(2016)·35 citations
10. 10*

    Phase transition in multi-scalar-singlet extensions of the Standard Model

    A. Tofighi🇮🇷 · O. N. Ghodsi🇮🇷 · M. Saeedhoseini🇮🇷

    We propose a generalization of the Standard Model (SM) by adding two real gaugesinglets S1, S2. The field S1 will improve the strength of the electroweak phase transition (EWPT). Imposing a Z2 symmetry on the field S2 makes this field a possible candidate for dark matter. Both singlets interact with other observable fields through Higgs boson. They are allowed to interact with each other as well. We find that by introducing two different scalar fields, the model is less vulnerable to experimental constraints. In this paper, we consider the effects of a heavy scalar(M1 > MH) on the electroweak phase transition. And we present configurations that produce a strong first order EWPT.

    hep-phPLB(2015)·7 citations
11. 11*

    Higgs Triplet Model with Classically Conformal Invariance

    Hiroshi Okada🇰🇷 · Yuta Orikasa🇰🇷 · Kei Yagyu🇬🇧

    We discuss an extension of the minimal Higgs triplet model with a classically conformal invariance and with a gauged $U(1{)}_{B-L}$ symmetry. In our scenario, tiny masses of neutrinos are generated by a hybrid contribution from the type-I and type-II seesaw mechanisms. The shape of the Higgs potential at low energies is determined by solving one-loop renormalization group equations for all the scalar quartic couplings with a set of initial values of parameters at the Planck scale. We find a successful set of the parameters in which the $U(1{)}_{B-L}$ symmetry is radiatively broken via the Coleman-Weinberg mechanism at the $\mathcal{O}$(10) TeV scale, and the electroweak symmetry breaking is also triggered by the $U(1{)}_{B-L}$ breaking. Under this configuration, we can predict various low energy observables such as the mass spectrum of extra Higgs bosons, and the mixing angles. Furthermore, using these predicted mass parameters, we obtain upper limits on Yukawa couplings among an isospin triplet Higgs field and lepton doublets from lepton flavor violation data.

    hep-ph17 citations
12. 12*

    Radiative decays of the neutral $Z_c(3900)$

    Dian-Yong Chen🇨🇳 · Yu-Bing Dong🇨🇳

    We study the radiative decays of the $Z_c(3900{)}^0$ in a hadronic molecule picture, where the $Z_c(3900)$ is treated as a $D{\bar{D}}^{\ast }+c.c$ hadronic molecule. The partial widths of $\Gamma (Z_c(3900{)}^0\to \gamma {\eta }_c(2S))$ and $\Gamma (Z_c(3900{)}^0\to \gamma {\chi }_{c0})$ are predicted to be of order 10 keV and the cross sections for $\sigma (e^{+}{e}^{-}\to {\pi }^0{Z}_c(3900)\to {\pi }^0\gamma {\eta }_c(2S))$ and $\sigma (e^{+}{e}^{-}\to {\pi }^0{Z}_c(3900)\to {\pi }^0\gamma {\chi }_{c0})$ are of order 0.1 pb at 4.23 GeV, which may be accessible for the BESIII and forthcoming BelleII.

    hep-phPRD(2016)·48 citations
13. 13*

    The nature of near-threshold XYZ states

    Martin Cleven🇨🇳 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Qian Wang🇩🇪 · Qiang Zhao🇨🇳

    We demonstrate that the recently observed $X$, $Y$, $Z$ states cannot be purely from kinematic effect. Especially the narrow near-threshold structures in elastic channels call for nearby poles of the $S$-matrix which are qualified as states. We propose a way to distinguish cusp effects from genuine states and demonstrate that (not all of) the recently observed $X$, $Y$, $Z$ states cannot be purely from kinematic effects. Especially, we show that the narrow near-threshold structures in elastic channels call for nearby poles of the $S$-matrix, since the normal kinematic cusp effect cannot produce that narrow structures in the elastic channels in contrast to genuine $S$-matrix poles. In addition, it is also discussed how spectra can be used to distinguish different scenarios proposed for the structure of those poles, such as hadro-quarkonia, tetraquarks and hadronic molecules. The basic tool employed is heavy quark spin symmetry.

    hep-phhep-exnucl-exnucl-thJPS Conf.Proc.(2016)·6 citations
14. 14*

    Neutron-antineutron oscillation and parity and CP symmetries

    Kazuo Fujikawa🇯🇵 · Anca Tureanu🇫🇮

    It is shown that the neutron-antineutron oscillation per se does not necessarily imply CP violation in an effective local Lorentz invariant description of the neutron which preserves CPT, contrary to a recent analysis in the literature. A CP- and baryon number-violating term can be transformed into a CP conserving one, thus rendering the CP violation spurious and unusable in the analysis of baryogenesis, for example. It is also shown that the neutron-antineutron oscillation in a $\Delta B=2$, Lorentz and CPT invariant interaction can occur only when parity is violated, irrespective of the CP properties; when parity is conserved, it is the ordinary quantum transition from neutron to antineutron which takes place. Those statements are proven by explicitly analyzing all the possible combinations with P, C and CP violation or their conservation. Moreover, a suitable combination of P=odd and P=even $\Delta B=2$ interactions in the present model is shown to give rise to the CP preserving mass term for the right-handed neutrino if one replaces the neutron by the neutrino, reinforcing the conclusion.

    hep-ph15 citations
15. 15*

    Deduction of $M(Sigmapi)$ for $Lambda(1405)$ with mixed $T_{Sigmapileftarrow{K}^{-}p}and{T}_{SigmapileftarrowSigmapi}$ from Hemingway's data

    Maryam Hassanvand🇯🇵 · Yoshinori Akaishi🇯🇵 · Toshimitsu Yamazaki🇯🇵

    We formulated the $Lambda(1405)$ (abbreviated as $Lambd{a}^{\ast }$) $rightarrow(Sigmapi{)}^0$ invariant-mass spectra produced in the $K^{-}+prightarrowSigm{a}^{+}(1660)+p{i}^{-}$, followed by $Sigm{a}^{+}(1660)rightarrowLambda(1405)+p{i}^{+}rightarrowSigmapi+p{i}^{+}$, processes at $p(K^{-})=4.2$ GeV/$c$, in which both the incident channel for a quasi-bound $K^{-}p$ state and its decay process to $(Sigmapi{)}^0$ were taken into account realistically. We calculated $M(Sigmapi)$ spectral shapes using mixed transition matrices, $T_{21}=T_{Sigmapileftarrow{K}^{-}p}$ and $T_{22}=T_{SigmapileftarrowSigmapi}$, for various theoretical models involving $Lambd{a}^{\ast }$. The asymmetric spectra were compared to old experimental data of Hemingway, and it was found that the mixing of the two channels, written as $(1-f),T_{21}+f,T_{22}$, gave a better result than considering the individual channels, yielding $f=0.376_{-0.019}^{+0.021}$, $M(Lambd{a}^{\ast })=1406.6_{-3.3}^{+3.4}$ MeV/$c^2$ and $Gamma=70pm2$ MeV, nearly consistent with the 2014 PDG values.

    hep-phnucl-thPRC(2015)·1 citation
16. 16*

    Photoproduction of $a_2(1320)$ in a Regge model

    Xiao-Yun Wang🇨🇳 · Alexey Guskov🇷🇺

    In this work, the photoproduction of $a_2(1320)$ off a proton target is investigated within an effective Lagrangian approach and the Regge model. The theoretical result indicates that the shapes of {the} total and differential cross sections of the $\gamma p\to a_2^{+}n$ reaction within the Feynman (isobar) model are much different from that of the Reggeized treatment. The obtained cross section is compared with the existing experimental results at low energies. The $a_2(1320)$ production cross section at high energies can be tested by the COMPASS experiment, which can provide important information for clarifying the role of the Reggeized treatment at that energy range.

    hep-phPRD(2016)·7 citations
17. 17*

    Photoproduction of the Scalar Meson $f_0(500)$

    Je-Hee Lee🇰🇷 · Hui-Young Ryu🇰🇷 · Byung-Geel Yu🇰🇷 · Hyun-Chul Kim🇰🇷

    In the present talk, we report a recent investigation on photoproduction of the $\gamma N\to f_0(500)N$ within a framework of the effective Lagrangian. We include the nucleon resonances with pin $1/2$ in the $s$ channel. The coupling constants have been etermined by assuming that the decay process $N^{\ast }\to (\pi \pi {)}_{I=0,J=0}N$ can be regarded as $N^{\ast }\to f_0(500)N$. We discuss the numerical results for the total cross sections and possible extension of the present work.

    hep-phhep-exnucl-exnucl-thJPS Conf.Proc.(2016)·0 citations
18. 18*

    Unquenched quark-model calculation of excited $\rho$ resonances and P-wave $\pi \pi$ phase shifts

    Susana Coito🇨🇳 · George Rupp🇵🇹 · Eef van Beveren🇵🇹

    The $\rho (770)$ vector resonance, its radial recurrences, and the corresponding P-wave $\pi \pi$ phase shifts are investigated in an unquenched quark model with all classes of relevant decay channels included, viz. pseudoscalar-pseudoscalar, vector-pseudoscalar, vector-vector, vector-scalar, axialvector-pseudoscalar, and axialvector-vector, totalling 26 channels. Two of the few model parameters are fixed at previously used values, whereas the other three are adjusted to the $\rho (770)$ resonance and the lower P-wave $\pi \pi$ phases. Preliminary results indicate the model's capacity to reproduce these phases as well as the $\rho$ mass and width. However, at higher energies the phase shifts tend to rise too sharply. A possible remedy is an extension of the model so as to handle resonances in the final states for most of the included decay channels. Work in progress.

    hep-phBled Workshops Phys.(2015)·3 citations
19. 19*

    Prospects of discovering new physics in rare charm decays

    Svjetlana Fajfer🇸🇮 · Nejc Košnik🇸🇮

    The LHCb bounds on the branching ratio of rare decay $D^0\to {\mu }^{+}{\mu }^{-}$ and the constraints on the branching ratio of $D^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$ in the nonresonant regions enable us to improve constraints on new physics contributions. Using the effective Lagrangian approach we determine sizes of the Wilson coefficients allowed by the existing LHCb bounds on rare charm decays. Then we discuss contributions to rare charm meson decay observables in several models of new physics: a model with an additional spin-1 weak triplet, leptoquark models, Two Higgs doublets model of type III, and a $Z^{\prime }$ model. Here we complement the discussion by $D^0-{\bar{D}}^0$ oscillations data. Among considered models, only leptoquarks can significantly modify Wilson coefficients. Assuming that the differential decay width for $D^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$ receives NP contribution, while the differential decay width for $D^{+}\to {\pi }^{+}{e}^{+}{e}^{-}$ is Standard Model-like, we find that lepton flavor universality can be violated and might be observed at high dilepton invariant mass.

    hep-phEPJC(2015)·100 citations
20. 20*

    Peculiar seasoning in the neutrino day-night asymmetry: where and when to look for spices?

    Oleg G. Kharlanov🇷🇺 · Andrey E. Lobanov🇷🇺

    We analyze the peculiar seasonal effects in the day-night asymmetry of solar neutrinos, namely those connected with the neutrino nighttime flux anomaly near the winter solstice. We show that, for certain placements of the neutrino detector, such effects may be within the reach of next-generation detectors.

    hep-phParticle Physics at the Year of Centenary…·0 citations
21. 21*

    Prospects for new physics searches at the LHC in the forward proton mode

    Sylvain Fichet🇧🇷

    The installation of forward proton detectors at the LHC will provide the possibility to observe central exclusive processes, opening a novel window on physics beyond the Standard Model. We review recent developments on the discovery potential from central exclusive light-by-light scattering. The search for this process is expected to provide bounds on a wide range of particles, and turns out to be complementary from new physics searches in inclusive channels.

    hep-phActa Phys.Polon.Supp.(2015)·10 citations
22. 22*

    Light-Front Holography and Superconformal Quantum Mechanics: A New Approach to Hadron Structure and Color Confinement

    S. J. Brodsky🇺🇸 · A. Deur🇺🇸 · G. F. de Teramond🇨🇷 · H. G. Dosch🇩🇪

    A primary question in hadron physics is how the mass scale for hadrons consisting of light quarks, such as the proton, emerges from the QCD Lagrangian even in the limit of zero quark mass. If one requires the effective action which underlies the QCD Lagrangian to remain conformally invariant and extends the formalism of de Alfaro, Fubini and Furlan to light-front Hamiltonian theory, then a unique, color-confining potential with a mass parameter $\kappa$ emerges. The actual value of the parameter $\kappa$ is not set by the model - only ratios of hadron masses and other hadronic mass scales are predicted. The result is a nonperturbative, relativistic light-front quantum mechanical wave equation, the Light-Front Schrödinger Equation which incorporates color confinement and other essential spectroscopic and dynamical features of hadron physics, including a massless pion for zero quark mass and linear Regge trajectories with the identical slope in the radial quantum number $n$ and orbital angular momentum $L$. The same light-front equations for mesons with spin $J$ also can be derived from the holographic mapping to QCD (3+1) at fixed light-front time from the soft-wall model modification of AdS${}_5$ space with a specific dilaton profile. Light-front holography thus provides a precise relation between the bound-state amplitudes in the fifth dimension of AdS space and the boost-invariant light-front wavefunctions describing the internal structure of hadrons in physical space-time. One can also extend the analysis to baryons using superconformal algebra - $2\times 2$ supersymmetric representations of the conformal group. The resulting fermionic LF bound-state equations predict striking similarities between the meson and baryon spectra. In fact, the holographic QCD light-front Hamiltonians for the states on the meson and baryon trajectories are identical if one shifts the internal angular...

    hep-phInt.J.Mod.Phys.Conf.Ser.(2015)·20 citations
23. 23*

    Minimal Models for Axion and Neutrino

    Y. H. Ahn🇰🇷 · Eung Jin Chun🇰🇷

    The PQ mechanism resolving the strong CP problem and the seesaw mechanism explaining the smallness of neutrino masses may be related in a way that the PQ symmetry breaking scale and the seesaw scale arise from a common origin. Depending on how the PQ symmetry and the seesaw mechanism are realized, one has different predictions on the color and electromagnetic anomalies which could be tested in the future axion dark matter search experiments. Motivated by this, we construct various PQ seesaw models which are minimally extended from the (non-) supersymmetric Standard Model and thus set up different benchmark points on the axion-photon-photon coupling in comparison with the standard KSVZ and DFSZ models.

    hep-phPLB(2016)·22 citations
24. 24*

    Simple mass matrices of neutrinos and quarks consistent with observed mixings and masses

    Hiroyuki Nishiura🇯🇵 · Takeshi Fukuyama🇯🇵

    We propose a simple phenomenological model of quarks-leptons mass matrices having fundamentally universal symmetry structure. These mass matrices consist of democratic and semi-democratic mass matrix terms commonly to the neutrino and the quark sectors and have only eight free parameters. We show that this mass matrix model well reproduces all the observed values of the MNS lepton and the CKM quark mixing angles, the neutrino mass squared difference ratio, and quark mass ratios, with an excellent agreement. The model also predicts ${\delta }_{CP}^{\ell }=-94^{\circ }$ for the leptonic $CP$ violating phase and $⟨m⟩\simeq 0.0073$ eV for the effective Majorana neutrino mass.

    hep-phPLB(2016)·6 citations
25. 25*

    Threshold Resummation for Polarized High-$p_T$ Hadron Production at COMPASS

    Claudia Uebler🇩🇪 · Andreas Schäfer🇩🇪 · Werner Vogelsang🇩🇪

    We study the cross section for the photoproduction process $\gamma N\to hX$ where the incident photon and nucleon are longitudinally polarized and a hadron $h$ is observed at high transverse momentum. Specifically, we address the "direct" part of the cross section, for which the photon interacts in a pointlike way. For this contribution we perform an all-order resummation of logarithmic threshold corrections generated by soft or collinear gluon emission to next-to-leading logarithmic accuracy. We present phenomenological results relevant for the COMPASS experiment and compare to recent COMPASS data.

    hep-phPRD(2015)·9 citations
26. 26*

    General $\epsilon$-representation for scalar one-loop Feynman integrals

    Johannes Bluemlein🇩🇪 · Khiem Hong Phan🇩🇪 · Tord Riemann🇩🇪

    A systematic study of the scalar one-loop two-, three-, and four-point Feynman integrals is performed. We consider all cases of mass assignment and external invariants and derive closed expressions in arbitrary space-time dimension in terms of higher transcendental functions. The integrals play a role as building blocks in general higher-loop or multi-leg processes. We also perform numerical checks of the calculations using AMBRE/MB and LoopTools/FF.

    hep-phNucl.Part.Phys.Proc.(2016)·5 citations
27. 27*

    Spectrum of heavy baryons in the quark model

    Tetsuya Yoshida🇯🇵 · Emiko Hiyama🇯🇵 · Atsushi Hosaka🇯🇵 · Makoto Oka🇯🇵 · Katsunori Sadato🇯🇵

    Single- and double- heavy baryons are studied in the constituent quark model. The model Hamiltonian is chosen as a standard one with two exceptions : (1) The color-Coulomb term depend on quark masses, and (2) an antisymmetric $LS$ force is introduced. Model parameters are fixed by the strange baryon spectra, $\Lambda$ and $\Sigma$ baryons. The masses of the observed charmed and bottomed baryons are, then, fairly well reproduced. Our focus is on the low-lying negative-parity states, in which the heavy baryons show specific excitation modes reflecting the mass differences of heavy and light quarks. By changing quark masses from the SU(3) limit to the strange quark mass, further to the charm and bottom quark masses, we demonstrate that the spectra change from the SU(3) symmetry patterns to the heavy quark symmetry ones.

    hep-phnucl-thPRD(2015)·283 citations
28. 28*

    From dimensional regularization to NLO computations in four dimensions

    German F. R. Sborlini🇦🇷 · Roger Hernandez-Pinto🇪🇸 · German Rodrigo🇪🇸

    Loop-tree duality (LTD) allows to express virtual contributions in terms of phase-space integrals, thus leading to a direct mapping with real radiation terms. We review the basis of the method and describe its application to regularize Feynman integrals. Performing an integrand-level combination of real and virtual terms, we show how to recover physical results by simply taking the four-dimensional limit of $d$-dimensional expressions. Moreover, this method provides a natural physical interpretation of infrared singularities, their origin and the way that they cancel in the complete computation.

    hep-phhep-thPoS(2015)·18 citations
29. 29*

    Effective Majorana Mass and Neutrinoless Double Beta Decay

    Giovanni Benato🇨🇭

    The probability distribution for the effective Majorana mass as a function of the lightest neutrino mass in the standard three neutrino scheme is computed via a random sampling from the distributions of the involved mixing angles and squared mass diffences. A flat distribution in the [0,2pi] range for the Majorana phases is assumed, and the dependence of small values of the effective mass on the Majorana phases is highlighted. The study is then extended with the addition of the cosmological bound on the sum of the neutrino masses. Finally, the prospects for neutrinoless double beta decay search with 76Ge, 130Te and 136Xe are discussed, as well as those for the measurement of the electron neutrino mass.

    hep-phEPJC(2015)·58 citations
30. 30*

    Low-mass right-handed gauge bosons from minimal grand unified theories

    Biswonath Sahoo. M. K. Parida (CETMS, Siksha 'O' Anusandhan University)

    Prediction of low-mass $W_R$ and $Z_R$ gauge bosons in popular grand unified theories has been the subject of considerable attention over the last three decades. In this work we show that when gravity induced corrections due to dim.5 operator are included the minimal symmetry breaking chain of $SO(10)$ and $E_6$ GUTs can yield $W_R^{\pm }$ and $Z_R$ bosons with masses in the range $(3-10)$ TeV which are accessible to experimental tests at the Large Hordan Collider. The RH neutrinos turn out to be heavy pseudo-Dirac fermions. The model can fit all fermion masses and manifest in rich structure of lepton flavor violation while proton life time is predicted to be much longer than the accessible limit of Super-Kamiokande or planned Hyper-Kamiokande collaborations.

    hep-phNucl.Part.Phys.Proc.(2016)·5 citations
31. 31*

    An MCMC study of general squark flavour mixing in the MSSM

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

    We present an extensive study of non-minimally flavour violating (NMFV) terms in the Lagrangian of the Minimal Supersymmetric Standard Model (MSSM). We impose a variety of theoretical and experimental constraints and perform a detailed scan of the parameter space by means of a Markov Chain Monte-Carlo (MCMC) setup. This represents the first study of several non-zero flavour-violating elements within the MSSM. We present the results of the MCMC scan with a special focus on the flavour-violating parameters. Based on these results, we define benchmark scenarios for future studies of NMFV effects at the LHC.

    hep-phPoS(2015)·0 citations
32. 32*

    Entropy production in chemically non-equilibrium quark-gluon plasma created in central Pb+Pb collisions at LHC energies

    V. Vovchenko🇩🇪 · M.I. Gorenstein🇺🇦 · L.M. Satarov🇩🇪 · I.N. Mishustin🇩🇪 · L.P. Csernai🇳🇴 · I. Kisel🇩🇪 · H. Stoecker🇩🇪

    We study the possibility that partonic matter produced at early stage of ultrarelativistic heavy-ion collisions is out of chemical equilibrium. It is assumed that initially this matter is mostly composed of gluons, but quarks and antiquarks are produced at later times. The dynamical evolution of partonic system is described by the Bjorken-like ideal hydrodynamics with a time dependent quark fugacity. The results of this model are compared with those obtained by assuming the complete chemical equilibrium of partons already at the initial stage. It is shown that in a chemically non-equilibrium scenario the entropy gradually increases, and about 25% of the total final entropy is generated during the hydrodynamic evolution of deconfined matter. We argue that the (anti)quark suppression included in this approach may be responsible for reduced (anti)baryon to meson ratios observed in heavy-ion collisions at LHC energies.

    hep-phnucl-thPRC(2016)·15 citations
33. 33*

    Vacuum Expectation Value Profiles of the Bulk Scalar Field in the Generalized Randall-Sundrum Model

    A. Tofighi🇮🇷 · M. Moazzen🇮🇷 · A. Farokhtabar🇮🇷

    In the generalized Randall-Sundrum warped brane-world model the cosmological constant induced on the visible brane can be positive or negative. In this paper we investigate profiles of vacuum expectation value of the bulk scalar field under general Dirichlet andNeumann boundary conditions in the generalized warped brane-worldmodel.We showthat the VEVprofiles generally depend on the value of the brane cosmological constant. We find that the VEV profiles of the bulk scalar field for a visible brane with negative cosmological constant and positive tension are quite distinct fromthose of Randall-Sundrum model. In addition we show that the VEV profiles for a visible brane with large positive cosmological constant are also different from those of the Randall- Sundrum model.We also verify that Goldberger andWise mechanism can work under nonzero Dirichlet boundary conditions in the generalized Randall-Sundrum model.

    ↳ gr-qchep-phhep-thAdv.High Energy Phys.(2015)·0 citations
34. 34*

    3D Structure and Nuclear Targets

    R. Dupré🇫🇷 · S. Scopetta🇮🇹

    Recent experimental and theoretical ideas are laying the ground for a new era in the knowledge of the parton structure of nuclei. We report on two promising directions beyond inclusive deep inelastic scattering experiments, aimed at, among other goals, unveiling the three dimensional structure of the bound nucleon. The 3D structure in coordinate space can be accessed through deep exclusive processes, whose non-perturbative content is parametrized in terms of generalized parton distributions. In this way the distribution of partons in the transverse plane will be obtained, providing a pictorial view of the realization of the European Muon Collaboration effect. In particular, we show how, through the generalized parton distribution framework, non nucleonic degrees of freedom in nuclei can be unveiled. Analogously, the momentum space 3D structure can be accessed by studying transverse momentum dependent parton distributions in semi-inclusive deep inelastic scattering processes. The status of measurements is also summarized, in particular novel coincidence measurements at high luminosity facilities, such as Jefferson Laboratory. Finally the prospects for the next years at future facilities, such as the 12~GeV Jefferson Laboratory and the Electron Ion Collider, are presented.

    ↳ nucl-exhep-exhep-phnucl-thEPJA(2016)·35 citations
35. 35*

    An effective method to accurately calculate the phase space factors for ${\beta }^{-}{\beta }^{-}$ decay

    Andrei Neacsu🇺🇸 · Mihai Horoi🇺🇸

    Accurate calculations of the electron phase space factors are necessary for reliable predictions of double-beta decay rates, and for the analysis of the associated electron angular and energy distributions. We present an effective method to calculate these phase space factors that takes into account the distorted Coulomb field of the daughter nucleus, yet allows one to easily calculate the phase space factors with good accuracy relative to the most exact methods available in the recent literature.

    ↳ nucl-thhep-phAdv.High Energy Phys.(2016)·29 citations
36. 36*

    Gravitational waves from dark matter collapse in a star

    Yasunari Kurita🇯🇵 · Hiroyuki Nakano🇯🇵

    We investigate the collapse of clusters of weakly interacting massive particles (WIMPs) in the core of a Sun-like star and the possible formation of mini-black holes and the emission of gravitational waves. When the number of WIMPs is small, thermal pressure balances the WIMP cluster's self gravity. If the number of WIMPs is larger than a critical number, thermal pressure cannot balance gravity and the cluster contracts. If WIMPs are collisionless and bosonic, the cluster collapses directly to form a mini-black hole. For fermionic WIMPs, the cluster contracts until it is sustained by Fermi pressure, forming a small compact object. If the fermionic WIMP mass is smaller than $4\times 10^2$ GeV, the radius of the compact object is larger than its Schwarzschild radius and Fermi pressure temporally sustains its self gravity, halting the formation of a black hole. If the fermionic WIMP mass is larger than $4\times 10^2$ GeV, the radius is smaller than its Schwarzschild radius and the compact object becomes a mini-black hole. If the WIMP mass is 1 TeV, the size of the black hole will be approximately 2.5 cm and ultra high frequency gravitational waves will be emitted during black hole formation. The central frequency $f_c$ of ringdown gravitational waves emitted from the black hole will be approximately 2 GHz. To detect the ringdown gravitational waves, the detector's noise must be below $\sqrt{S_h(f_c)}\approx 10^{-30}/\sqrt{\mathrm{Hz}}$.

    ↳ gr-qcastro-ph.SRhep-phPRD(2016)·24 citations
37. 37*

    Three particles in a finite volume

    Akaki Rusetsky (Bonn U., HISKP)🇩🇪

    The volume-dependence of a shallow three-particle bound state in the cubic box with a size $L$ is studied. It is shown that, in the unitary limit, the energy-level shift from the infinite-volume position is given by $\Delta E=c({\kappa }^2/m)(\kappa L{)}^{-3/2}|A{|}^2\exp (-2\kappa L/\sqrt{3})$, where $\kappa$ is the bound-state momentum and $|A{|}^2$ denotes the three-body analog of the asymptotic normalization constant, which encodes the information about the short-range interactions in the three-body system.

    ↳ hep-lathep-phPoS(2016)·0 citations
38. 38*

    On the upper limits for dipole anisotropies in cosmic-ray positrons

    J. Berdugo · J. Casaus · C. Mana · M.A. Velasco

    The excess of cosmic-ray positrons in the energy range from 10 GeV to few hundred GeV reported by PAMELA and AMS experiments is not consistent with a pure secondary origin and requires the introduction of a source term. The presence of anisotropies in the positron arrival directions would be a distinctive signature of their origin. Current measurements are consistent with isotropy and limits to a dipole anisotropy have been established. In this note, we review the mathematical basis of this analysis and provide a general bound to the dipole upper limits achievable from a given sample of events. The published experimental limits are confronted with this bound.

    ↳ astro-ph.IMastro-ph.HEhep-ph1 citation
39. 39*

    Can Schwarzschild Black Holes Be Accelerators of Spinning Massive Particles?

    Cristóbal Armaza🇨🇱 · Máximo Bañados🇨🇱 · Benjamin Koch🇨🇱

    It is known that the center-of-mass energy of the collision of two massive particles following geodesics around a black hole presents a maximum. The maximum energy increases when the black hole is endowed with spin, and for a maximally rotating hole this energy blows up, offering, in principle, a unique probe of fundamental physics. This work extends the latter studies by considering that the colliding particles possess intrinsic angular momentum (spin), described by the Hanson-Regge-Hojman theory of spinning particles. By analyzing planar trajectories of spinning particles around non-rotating black holes, a significant increase of the invariant collision energy is found. Radial turning points, causality constraints, and limitations of the theory are discussed.

    ↳ gr-qchep-phClass.Quant.Grav.(2016)·56 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.