Wed·Aug 31, 2016Wednesday·August 31, 2016

1. 01*

   Analysis of $X(3872)$ production via Heavy-Meson Effective Theory

   L. M. Abreu🇧🇷

   We analyze the $X(3872)$ production in the processes $\bar{D}D\to \pi X$, ${\bar{D}}^{\ast }D\to \pi X$ and ${\bar{D}}^{\ast }{D}^{\ast }\to \pi X$, making use of the Heavy-Meson Effective Theory, with an effective Lagrangian built based on chiral $SU(3{)}_L\times SU(3{)}_R$ and heavy quark symmetries. In this scenario, we consider $X$ as a bound state of $D^{\ast }\bar{D}+c.c.$, including neutral and charged components, and obtain the cross sections the mentioned reactions as function of collision energy.

   hep-phPTEP(2016)·7 citations
2. 02*

   Accessing the real part of the forward $J/\psi$-p scattering amplitude from $J/\psi$ photo-production on protons around threshold

   Oleksii Gryniuk🇩🇪 · Marc Vanderhaeghen🇩🇪

   We provide an updated analysis of the forward $J/\psi$-p scattering amplitude, relating its imaginary part to $\gamma p\to J/\psi p$ and $\gamma p\to c\bar{c}X$ cross section data, and calculating its real part through a once-subtracted dispersion relation. From a global fit to both differential and total cross section data, we extract a value for the spin-averaged $J/\psi$-p s-wave scattering length $a_{\psi p}=0.046\pm 0.005$ fm, which can be translated into a $J/\psi$ binding energy in nuclear matter of $B_{\psi }=2.7\pm 0.3$ MeV. We estimate the forward-backward asymmetry to the $\gamma p\to e^{-}{e}^{+}p$ process around the $J/\psi$ resonance, which results from interchanging the leptons in the interference between the $J/\psi$ production and the Bethe-Heitler mechanisms. We show that to good approximation this asymmetry depends linearly on $a_{\psi p}$, and can reach values around -25% for forthcoming $J/\psi$ threshold production experiments at Jefferson Lab. Its measurement can thus provide a very sensitive observable for a refined extraction of $a_{\psi p}$.

   hep-phPRD(2016)·69 citations
3. 03*

   Lattice-motivated holomorphic nearly perturbative QCD

   Cesar Ayala🇪🇸 · Gorazd Cvetic🇨🇱 · Reinhart Kogerler🇩🇪

   Newer lattice results indicate that, in the Landau gauge at low spacelike momenta, the gluon propagator and the ghost dressing function are finite nonzero. This leads to a definition of the QCD running coupling, in a specific scheme, that goes to zero at low spacelike momenta. We construct a running coupling which fulfills these conditions, and at the same time reproduces to a high precision the perturbative behavior at high momenta. The coupling is constructed in such a way that it reflects qualitatively correctly the holomorphic (analytic) behavior of spacelike observables in the complex plane of the squared momenta, as dictated by the general principles of Quantum Field Theories. Further, we require the coupling to reproduce correctly the nonstrange semihadronic decay rate of tau lepton which is the best measured low-momentum QCD observable with small higher-twist effects. Subsequent application of the Borel sum rules to the V+A spectral functions of tau lepton decays, as measured by OPAL Collaboration, determines the values of the gluon condensate and of the V+A 6-dimensional condensate, and reproduces the data to a significantly higher precision than the usual MSbar running coupling.

   hep-phJ.Phys.G(2017)·23 citations
4. 04*

   Self-Interacting Dark Matter with Naturally Light Mediator

   Ernest Ma (UC Riverside)🇺🇸

   A promising proposal for resolving the cusp-core anomaly in the density profile of dwarf galaxies is to allow dark matter to interact with itself through a light mediator of mass much less than a GeV. The theoretical challenge is to have a complete renormalizable theory where this happens naturally even though dark matter itself may be of the electroweak scale, i.e. 100 GeV to 1 TeV. I propose here such a model, with just two neutral complex scalar singlets under a softly broken dark global U(1) symmetry.

   hep-phastro-ph.COMod.Phys.Lett.A(2017)·7 citations
5. 05*

   The influence of chiral chemical potential, parallel electric and magnetic fields on the critical temperature of QCD

   M. Ruggieri🇨🇳 · Z. Y. Lu🇨🇳 · G. X. Peng🇨🇳

   We study the influence of external electric, $E$, and magnetic, $B$, fields parallel to each other, and of a chiral chemical potential, ${\mu }_5$, on the chiral phase transition of Quantum Chromodynamics. Our theoretical framework is a Nambu-Jona-Lasinio model with a contact interaction. Within this model we compute the critical temperature of chiral symmetry restoration, $T_c$, as a function of the chiral chemical potential and field strengths. We find that the fields inhibit and ${\mu }_5$ enhances chiral symmetry breaking, in agreement with previous studies.

   hep-phhep-latnucl-thPRD(2016)·32 citations
6. 06*

   Astroparticles and tests of Lorentz invariance

   Jorge S. Diaz🇩🇪

   Searches for violations of Lorentz invariance using cosmic rays, gamma rays, and astrophysical neutrinos and the prospects for future tests using cosmic-ray showers are presented.

   hep-ph0 citations
7. 07*

   Masses and decay widths of radially excited Bottom mesons

   Pallavi Gupta🇮🇳 · A. Upadhyay🇮🇳

   Inspired from the experimental information coming from LHC [2,3] and Babar [4] for radially higher excited charmed mesons, we predict the masses and decays of the n=2 S-wave and P- wave bottom mesons using the effective lagrangian approach. Using heavy quark effective theory approach, non-perturbative parameters (?, ?1 and ?2) are fitted using the available experimental and theoretical informations on charm masses. Using heavy quark symmetry and the values of these fitted parameters, the masses of radially excited even and odd parity bottom mesons with and without strangness are predicted. These predicted masses led in constraining the decay widths of these 12 states, and also shed light on the unknown values of the higher hadronic coupling constants eeg 2 SH and eeg 2 TH. Studying the properties like masses, decays of 2S and 2P states and some hadronic couplings would help forthcoming experiments to look into these states in future.

   hep-ph0 citations
8. 08*

   Renormalisation Group Corrections to Neutrino Mixing Sum Rules

   J. Gehrlein🇩🇪 · S. T. Petcov🇮🇹 · M. Spinrath🇩🇪 · A. V. Titov🇮🇹

   Neutrino mixing sum rules are common to a large class of models based on the (discrete) symmetry approach to lepton flavour. In this approach the neutrino mixing matrix $U$ is assumed to have an underlying approximate symmetry form ${\tilde{U}}_{\nu }$, which is dictated by, or associated with, the employed (discrete) symmetry. In such a setup the cosine of the Dirac CP-violating phase $\delta$ can be related to the three neutrino mixing angles in terms of a sum rule which depends on the symmetry form of ${\tilde{U}}_{\nu }$. We consider five extensively discussed possible symmetry forms of ${\tilde{U}}_{\nu }$: i) bimaximal (BM) and ii) tri-bimaximal (TBM) forms, the forms corresponding to iii) golden ratio type A (GRA) mixing, iv) golden ratio type B (GRB) mixing, and v) hexagonal (HG) mixing. For each of these forms we investigate the renormalisation group corrections to the sum rule predictions for $\delta$ in the cases of neutrino Majorana mass term generated by the Weinberg (dimension 5) operator added to i) the Standard Model, and ii) the minimal SUSY extension of the Standard Model.

   hep-phJHEP(2016)·22 citations
9. 09*

   Generalized Parton Distributions: confining potential effects within AdS/QCD

   Marco Claudio Traini🇮🇹

   Generalized Parton Distributions are investigated within a holographic approach where the string modes in the fifth dimension describe the nucleon in a bottom-up or AdS/QCD framework. The aim is to bring the AdS/QCD results in the realm of phenomenology in order to extract consequences and previsions. Two main aspects are studied: i) the role of the confining potential needed for breaking conformal invariance and introducing confinement (both: classic Soft-Wall and recent Infra-Red potentials are investigated); ii) the extension of the predicted GPDs to the entire range of off-forward kinematics by means of Double-Distributions. Higher Fock states are included describing the nucleon as a superposition of three valence quarks and quark-antiquark pairs and gluons.

   hep-phEPJC(2017)·17 citations
10. 10*

    Exotic Higgs Decay $h\to \varphi \varphi \to 4b$ at the LHeC

    Shang Liu🇨🇳 · Yi-Lei Tang🇨🇳 · Chen Zhang🇨🇳 · Shou-hua Zhu🇨🇳

    We study the exotic decay of the 125 GeV Higgs boson ($h$) into a pair of light spin-0 particles ($\varphi$) which subsequently decays and results in a $4b$ final state. This decay mode is well motivated in the Next to Minimal Supersymmetric Standard Model (NMSSM) and extended Higgs sector models. Instead of searching at the Large Hadron Collider (LHC) and the High Luminosity Large Hadron Collider (HL-LHC) which are beset by large Standard Model (SM) backgrounds, we investigate this decay channel at the much cleaner Large Hadron Electron Collider (LHeC). With some simple selection cuts this channel becomes nearly free of background at this $ep$ machine, in stark contrast with the situation at the (HL-)LHC. With a parton level analysis we show that for the $\varphi$ mass range $[20,60]GeV$, with $100f{b}^{-1}$ luminosity the LHeC is generally capable of constraining $C_{4b}^2\equiv {\kappa }_V^2\times \text{Br}(h\to \varphi \varphi )\times {\text{Br}}^2(\varphi \to b\bar{b})$ (${\kappa }_V$ denotes the $hVV(V=W,Z)$ coupling strength relative to the SM value) to a few percent level ($95\%$ CLs). With $1a{b}^{-1}$ luminosity $C_{4b}^2$ at a few per mille level can be probed. These sensitivities are much better than the HL-LHC performance and demonstrate the important role expected to be played by the LHeC in probing exotic Higgs decay processes, in addition to the already proposed invisible Higgs decay channel.

    hep-phEPJC(2017)·21 citations
11. 11*

    Leptoquark model to explain the $B$-physics anomalies, $R_K$ and $R_D$

    Damir Bečirević🇫🇷 · Svjetlana Fajfer🇸🇮 · Nejc Košnik🇸🇮 · Olcyr Sumensari🇫🇷

    We show that a model with a scalar leptoquark of hypercharge $Y=1/6$ which includes the light right-handed neutrinos, can successfully describe both of the $B$-physics anomalies, $R_K^{\exp }<R_K^{\mathrm{SM}}$ and $R_D^{\exp }>R_D^{\mathrm{SM}}$. We discuss the corresponding low energy effective theory and, after using the known experimental data as constraints, we show that the model is viable and that it offers several predictions which can be tested experimentally.

    hep-phhep-exPRD(2016)·306 citations
12. 12*

    Obtaining nonvanishing ${\theta }_{13}$ with constrained neutrino Yukawa matrix and implications for flavor model buildings

    Ya Zhao🇨🇳

    Assuming a diagonal Majorana neutrino mass matrix, we investigate the neutrino Yukawa textures which lead to a non-zero reactor mixing angle ${\theta }_{13}$. The neutrino effective coupling matrix ${\kappa }^{eff}$ is pre-diagonalized by a constant mixing pattern $V_{\nu }$ with a vanishing ${\theta }_{13}^{\nu }$. The resulting pre-diagonal symmetrical matrix $\kappa$ is set to be four texture zeros with two types of off-diagonal elements nonzero, which is ${\kappa }_{13}$ and ${\kappa }_{23}$, respectively. With the expectation of simple textures we thoroughly classify the linear combinations, ${\alpha }_i$, ${\beta }_i$ and ${\gamma }_i$ of Yukawa elements ${\lambda }_{ij}$ in a same row, according to the values vanishing or not. Each set of the classifications can lead to a Yukawa texture which may have implications for the discrete flavor model buildings. We also present a model based on $A_4$ according to one set of the constraints on the three combinations with a specific choice of a coefficient in Yukawa texture.

    hep-phMod.Phys.Lett.A(2017)·0 citations
13. 13*

    Summary of WG6: Spin Physics

    Emanuele Nocera🇬🇧 · Silvia Pisano🇮🇹

    The working group on Spin Physics at the XXIV International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2016) witnessed a significant progress in the theoretical and experimental investigations aiming at unveiling the innermost structure of the proton. Results ranged from proton's one-dimensional representation to its multi-dimensional imaging. In this contribution, we summarize a selection of the topics discussed and of the results presented. For details, we refer to the individual contributions collected in the proceedings of this workshop.

    hep-phPoS(2016)·4 citations
14. 14*

    Neutrino Masses, Scale-Dependent Growth, and Redshift-Space Distortions

    Oscar F. Hernández🇨🇦

    Massive neutrinos leave a unique signature in the large scale clustering of matter. We investigate the wavenumber dependence of the growth factor arising from neutrino masses and use a Fisher analysis to determine the aspects of a galaxy survey needed to measure this scale dependence.

    ↳ astro-ph.COhep-phJCAP(2017)·15 citations
15. 15*

    Axion decay constants at special points in type II string theory

    Masaki Honda🇯🇵 · Akane Oikawa🇯🇵 · Hajime Otsuka🇯🇵

    We propose the mechanism to disentangle the decay constant of closed string axion from the string scale in the framework of type II string theory on Calabi-Yau manifold. We find that the quantum and geometrical corrections in the prepotential that arise at some special points in the moduli space widen the window of axion decay constant. In particular, around the small complex structure points, the axion decay constant becomes significantly lower than the string scale. We also discuss the moduli stabilization leading to the phenomenologically attractive low-scale axion decay constant.

    ↳ hep-thhep-phJHEP(2017)·3 citations
16. 16*

    Poincaré, Scale and Conformal Symmetries: Gauge Perspective and Cosmological Ramifications

    Georgios K. Karananas🇨🇭

    In the first part of the thesis we focus on local symmetries. We review a self-consistent framework that we employed in order to discuss the dynamics of the theories of interest. Its merit lies in that we can make the symmetry group act internally and thus be effectively separated from coordinate transformations. We investigate under which conditions it is not needed to introduce extra compensating fields to make relativistic as well as nonrelativistic theories invariant under local symmetries and more precisely under scale transformations. We clarify the role that torsion plays in this context. We highlight the difference between Weyl and conformal invariance and we demonstrate that not all conformal theories can be coupled to gravity in a Weyl invariant way. Once this minimalistic treatment for gauging symmetries is left aside, new possibilities appear. Namely, if we consider the Poincaré group, the presence of the extra modes leads to nontrivial particle dynamics. We derive constraints such that the theory is free from pathologies. In the second part we make clear that even when not gauged, the presence of scale invariance is appealing. First, it makes possible for the dimensionful parameters that appear in a theory to be generated dynamically and be sourced by the vacuum expectation value of the dilaton. If the Standard Model is embedded into a scale-invariant framework, a number of interesting implications for cosmology arise. The inflationary stage of our Universe and its present-day acceleration become linked, a connection that might give us insight into the dark energy dynamics. We show that in the context of gravitational theories which are invariant under restricted coordinate transformations, the dilaton instead of being introduced ad hoc, can emerge from the gravitational part of a theory. We discuss the consequences of the nontrivial way this field emerges in the action.

    ↳ hep-thastro-ph.COgr-qchep-ph12 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.