Thu·Jul 6, 2017Thursday·July 6, 2017

1. 01*

   Refining the scalar and tensor contributions in $\tau \to \pi \pi \pi {\nu }_{\tau }$ decays

   Juan Jose Sanz-Cillero🇪🇸 · Olga Shekhovtsova🇵🇱

   In this article we analyze the contribution from intermediate spin-0 and spin-2 resonances to the $\tau \to \nu \pi \pi \pi$ decay by means of a chiral invariant Lagrangian incorporating these mesons. In particular, we study the corresponding axial-vector form-factors. The advantage of this procedure with respect to previous analyses is that it incorporates chiral (and isospin) invariance and, hence, the partial conservation of the axial-vector current. This ensures the recovery of the right low-energy limit, described by chiral perturbation theory, and the transversality of the current in the chiral limit at all energies. Furthermore, the meson form-factors are further improved by requiring appropriate QCD high-energy conditions. We end up with a brief discussion on its implementation in the Tauola Monte Carlo and the prospects for future analyses of Belle's data.

   hep-phJHEP(2017)·14 citations
2. 02*

   Exotic tetraquark states with the $qq\bar{Q}\bar{Q}$ configuration

   Si-Qiang Luo🇨🇳 · Kan Chen🇨🇳 · Xiang Liu🇨🇳 · Yan-Rui Liu🇨🇳 · Shi-Lin Zhu🇨🇳

   In this work, we study systematically the mass splittings of the $qq\bar{Q}\bar{Q}$ ($q=u$, $d$, $s$ and $Q=c$, $b$) tetraquark states with the color-magnetic interaction by considering color mixing effects and estimate roughly their masses. We find that the color mixing effect is relatively important for the $J^P=0^{+}$ states and possible stable tetraquarks exist in the $nn\bar{Q}\bar{Q}$ ($n=u$, $d$) and $ns\bar{Q}\bar{Q}$ systems either with $J=0$ or with $J=1$. Possible decay patterns of the tetraquarks are briefly discussed.

   hep-phhep-exhep-latnucl-ex+1EPJC(2017)·152 citations
3. 03*

   Hidden Bottom Pentaquark States with Spin 3/2 and 5/2

   K. Azizi🇹🇷 · Y. Sarac🇹🇷 · H. Sundu🇹🇷

   Theoretical investigations of the pentaquark states which were recently discovered provide important information on their nature and structure. It is necessary to study the spectroscopic parameters like masses and residues of particles belong to the class of pentaquarks and ones having similar structures. The mass and pole residue are quantities which emerge as the main input parameters in exploration of the electromagnetic, strong and weak interactions of the pentaquarks with other hadrons in many frameworks. This work deals with a QCD sum rule analysis of the spin-$3/2$ and spin-$5/2$ bottom pentaquarks with both positive and negative parities aiming to evaluate their masses and residues. In calculations, the pentaquark states are modeled by molecular-type interpolating currents: for particles with $J=5/2$ a mixing current is used. We compare the results obtained in this work with the existing predictions of other theoretical studies. The predictions on the masses may shed light on experimental searches of the bottom pentaquarks.

   hep-phhep-exhep-latPRD(2017)·32 citations
4. 04*

   Matter Parity Violating Dark Matter Decay in Minimal SO(10), Unification, Vacuum Stability and Verifiable Proton Decay

   Biswonath Sahoo (1)🇮🇳 · M. K Parida (1)🇮🇳 · Mainak Chakraborty (1) ((1) Siksha 'O' Anusandhan University)🇮🇳

   In direct breaking of non-supersymmetric SO(10) to the standard model, we investigate the possibility that dark matter (DM) decaying through its mixing with right-handed neutrino (RH$\nu$) produces high energy IceCube neutrinos having type-I seesaw masses. Instead of one universal mixing and one common heavy RH$\nu$ mass proposed in a recent standard model extension, we find that underlying quark-lepton symmetry resulting in naturally hierarchical RH$\nu$ masses predict a separate mixing with each of them. We determine these mixings from the seesaw prediction of the DM decay rates into the light neutrino flavors. We further show that these mixings originate from Planck-scale assisted spontaneously broken matter parity needed to resolve the associated cosmological domain wall problem. This leads to the prediction of a new LHC accessible matter-parity odd Higgs scalar which also completes vacuum stability in the Higgs potential for its mass $M_{{\chi }_S}\simeq 178$ GeV. Two separate minimal SO(10) models are further noted to predict such dark matter dynamics where a single scalar submultiplet from ${126}_H^{†}$ or ${210}_H$ of intermediate mass achieves precision gauge coupling unification. Despite the presence of two large Higgs representations and the fermionic dark matter host, ${45}_F$, experimentally accessible proton lifetimes are also predicted with reduced uncertainties.

   hep-phNPB(2019)·12 citations
5. 05*

   Study of Electromagnetic Properties of Light Baryons in the Hypercentral Approach

   Zahra Ghalenovi🇮🇷

   Light flavour baryons are studied in a non-relativistic potential model with colour Coulomb plus linear confinement potential using a simple variational method. The ground-state masses and magnetic moments of the light baryons are computed using a spin- and isospin-dependent potential. We extend our scheme to predict the transition magnetic moments of $B_{(J^P={3/2}^{+})}\to B_{(J^P={1/2}^{+})}\gamma$ processes. We also compute the radiative decay widths and branching ratios of light baryons. A comparison of our results with those of other works and experimental data is also presented.

   hep-phInt.J.Theor.Phys.(2018)·4 citations
6. 06*

   Summary of CKM 2016 Working Group 4 : mixing and mixing-related $CP$ violation in the $B$ system

   Alessandro Gaz🇯🇵 · Vladimir V. Gligorov🇫🇷 · Dean Robinson🇺🇸

   We summarize the new results on $B$ meson mixing and mixing-related $CP$ violation presented at CKM2016. We place these results in the context of both previous experimental measurements and the most recent theoretical developments in the field, and discuss prospects for ongoing and future mixing and mixing-related $CP$ violation measurements.

   hep-phhep-exhep-latPoS(2017)·0 citations
7. 07*

   Bilepton Signatures at the LHC

   Gennaro Corcella🇮🇹 · Claudio Coriano🇮🇹 · Antonio Costantini🇮🇹 · Paul H. Frampton🇮🇹

   We discuss the main signatures of the Bilepton Model at the Large Hadron Collider, focusing on its gauge boson sector. The model is characterised by five additional gauge bosons, four charged and one neutral, beyond those of the Standard Model, plus three exotic quarks. The latter turn into ordinary quarks with the emission of bilepton doublets $(Y^{++},Y^{+})$ and $(Y^{--},Y^{-})$ of lepton number $L=-2$ and $L=+2$ respectively, with the doubly-charged bileptons decaying into same-sign lepton pairs. We perform a phenomenological analysis investigating processes with two doubly-charged bileptons and two jets at the LHC and find that, setting suitable cuts on pseudorapidities and transverse momenta of final-states jets and leptons, the model yields a visible signal and the main Standard Model backgrounds can be suppressed. Compared to previous studies, our investigation is based on a full Monte Carlo implementation of the model and accounts for parton showers, hadronization and an actual jet-clustering algorithm for both signal and Standard Model background, thus providing an optimal framework for an actual experimental search.

   hep-phPLB(2017)·28 citations
8. 08*

   Second Octant Favored for Non-Maximal ${\theta }_{23}$

   Paul H. Frampton🇮🇹

   One of the most robust relationships predicted by binary tetrahedral ($T^{{}^{\prime }}$) flavor symmetry relates the reactor neutrino angle ${\theta }_{13}$ to the atmospheric neutrino angle ${\theta }_{23}$, independently of ${\theta }_{12}$. It has the form ${\theta }_{13}=\sqrt{2}|\frac{\pi }{4}-{\theta }_{23}|$. When this prediction first appeared in 2008, ${\theta }_{13}$ was consistent with zero and ${\theta }_{23}$ with $\pi /4$. Non-zero ${\theta }_{13}$ was established by Daya Bay in 2012. Non-zero $|\frac{\pi }{4}-{\theta }_{23}|$ is now favored by the NO$\nu$A experiment and, for ${\theta }_{23}$, the aforementioned $T^{{}^{\prime }}$ relation selects the second octant (${\theta }_{23}>\frac{\pi }{4}$) over the first octant (${\theta }_{23}<\frac{\pi }{4}$). This analysis initially assumes CP conservation in the lepton sector, but leptonic CP violation is discussed and it is shown that this specific $T^{{}^{\prime }}$ relationship is invariant.

   hep-phMod.Phys.Lett.A(2017)·1 citation
9. 09*

   Wigner functions of massive fermions in strong magnetic fields

   Xin-li Sheng🇨🇳 · Dirk H. Rischke🇩🇪 · David Vasak🇩🇪 · Qun Wang🇨🇳

   We compute the covariant Wigner function for spin-1/2 fermions in an arbitrarily strong magnetic field by exactly solving the Dirac equation at non-zero fermion-number and chiral-charge densities. The Landau energy levels as well as a set of orthonormal eigenfunctions are found as solutions of the Dirac equation. With these orthonormal eigenfunctions we construct the fermion field operators and the corresponding Wigner-function operator. The Wigner function is obtained by taking the ensemble average of the Wigner-function operator in global thermodynamical equilibrium, i.e., at constant temperature $T$ and non-zero fermion-number and chiral-charge chemical potentials $\mu$ and ${\mu }_5$, respectively. Extracting the vector and axial-vector components of the Wigner function, we reproduce the currents of the chiral magnetic and separation effect in an arbitrarily strong magnetic field.

   hep-phEPJA(2018)·45 citations
10. 10*

    Vector SIMP dark matter

    Soo-Min Choi🇰🇷 · Yonit Hochberg🇺🇸 · Eric Kuflik🇺🇸 · Hyun Min Lee🇰🇷 · Yann Mambrini🇫🇷 · Hitoshi Murayama🇺🇸 · Mathias Pierre🇫🇷

    Strongly Interacting Massive Particles (SIMPs) have recently been proposed as light thermal dark matter relics. Here we consider an explicit realization of the SIMP mechanism in the form of vector SIMPs arising from an $SU(2{)}_X$ hidden gauge theory, where the accidental custodial symmetry protects the stability of the dark matter. We propose several ways of equilibrating the dark and visible sectors in this setup. In particular, we show that a light dark Higgs portal can maintain thermal equilibrium between the two sectors, as can a massive dark vector portal with its generalized Chern-Simons couplings to the vector SIMPs, all while remaining consistent with experimental constraints.

    hep-phJHEP(2017)·78 citations
11. 11*

    Decoupling of the leading contribution in the discrete BFKL Analysis of High-Precision HERA Data

    H. Kowalski🇩🇪 · L.N. Lipatov🇷🇺 · D.A. Ross🇬🇧 · O. Schulz🇩🇪

    We analyse, in NLO, the physical properties of the discrete eigenvalue solution for the BFKL equation. We show that a set of eigenfunctions with positive eigenvalues, \omega, together with a small contribution from a continuum of eigenfunctions with negative \omega, provide an excellent description of high-precision HERA F_2 data in the region, x<0.001, Q^2 > 6 GeV^2. The phases of the eigenfunctions can be obtained from a simple parametrisation of the pomeron spectrum, which has a natural motivation within BFKL. The data analysis shows that the first eigenfunction decouples completely or almost completely from the proton. This suggests that there exist an additional ground state, which is naturally saturated and may have the properties of the soft pomeron.

    hep-phEPJC(2017)·21 citations
12. 12*

    Dark forces coupled to non-conserved currents

    Jeff A. Dror🇺🇸 · Robert Lasenby🇨🇦 · Maxim Pospelov🇨🇦

    New light vectors with dimension-4 couplings to Standard Model states have (energy / vector mass)^2 enhanced production rates unless the current they couple to is conserved. These processes allow us to derive new constraints on the couplings of such vectors, that are significantly stronger than the previous literature for a wide variety of models. Examples include vectors with axial couplings to quarks and vectors coupled to currents (such as baryon number) that are only broken by the chiral anomaly. Our new limits arise from a range of processes, including rare Z decays and flavor changing meson decays, and rule out a number of phenomenologically-motivated proposals.

    hep-phhep-exPRD(2017)·196 citations
13. 13*

    CMB spectral distortions in generic two-field models

    Kimmo Kainulainen🇫🇮 · Juuso Leskinen🇫🇮 · Sami Nurmi🇫🇮 · Tomo Takahashi🇯🇵

    We investigate the CMB $\mu$ distortion in models where two uncorrelated sources contribute to primordial perturbations. We parameterise each source by an amplitude, tilt, running and running of the running. We perform a detailed analysis of the distribution signal as function of the model parameters, highlighting the differences compared to single-source models. As a specific example, we also investigate the mixed inflaton-curvaton scenario. We find that the $\mu$ distortion could efficiently break degeneracies of curvaton parameters especially when combined with future sensitivity of probing the tensor-to-scalar ratio $r$. For example, assuming bounds $\mu <0.5\times 10^{-8}$ and $r<0.01$, the curvaton contribution should either vanish or the curvaton should dominate primordial perturbations and its slow-roll parameter ${\eta }_{\chi }$ is constrained to the interval $-0.007<{\eta }_{\chi }<0.045$.

    ↳ astro-ph.COhep-phJCAP(2017)·10 citations
14. 14*

    Momentum vortices on pairs production by two counter-rotating fields

    Z. L. Li🇨🇳 · Y. J. Li🇨🇳 · B. S. Xie🇨🇳

    Multiphoton pair production is investigated by focusing on the momentum structures of produced pairs in the polarization plane for the two circularly polarized fields. Upon the momentum spectra, different from the concentric rings with the familiar Ramsey interference fringes for the same handedness, however, the obvious vortex structures are found constituted by the Archimedean spirals for two opposite handedness fields. The underlying physical reasons are analyzed and discussed. It is also found that the vortex patterns are sensitive to the relative carrier envelope phase, the time delay, and the handedness of two fields, which can be used to detect the applied laser field characteristics as a probe way.

    ↳ quant-phhep-phPRD(2017)·45 citations
15. 15*

    Gravitational Waves from Primordial Black Hole Mergers

    Martti Raidal🇪🇪 · Ville Vaskonen🇪🇪 · Hardi Veermäe🇪🇪

    We study the production of primordial black hole (PBH) binaries and the resulting merger rate, accounting for an extended PBH mass function and the possibility of a clustered spatial distribution. Under the hypothesis that the gravitational wave events observed by LIGO were caused by PBH mergers, we show that it is possible to satisfy all present constraints on the PBH abundance, and find the viable parameter range for the lognormal PBH mass function. The non-observation of gravitational wave background allows us to derive constraints on the fraction of dark matter in PBHs, which are stronger than any other current constraint in the PBH mass range $0.5-30M_{\odot }$. We show that the predicted gravitational wave background can be observed by the coming runs of LIGO, and non-observation would indicate that the observed events are not of primordial origin. As the PBH mergers convert matter into radiation, they may have interesting cosmological implications, for example, in the context of relieving the tension between the high and low redshift measurements of the Hubble constant. However, we find that these effects are negligible as, after recombination, no more that $1\%$ of DM can be converted into gravitational waves.

    ↳ astro-ph.COhep-phJCAP(2017)·384 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.