Wed·Aug 8, 2018Wednesday·August 8, 2018

1. 01*

   A composite pNGB leptoquark at the LHC

   Ezequiel Alvarez🇦🇷 · Leandro Da Rold🇦🇷 · Aurelio Juste🇪🇸 · Manuel Szewc🇦🇷 · Tamara Vazquez Schroeder🇨🇭

   The measurements of $R_K^{(\ast )}$ and $R_D^{(\ast )}$ by BaBar, Belle and the LHCb collaborations could be showing a hint of lepton flavor universality violation that can be accommodated by the presence of suitable leptoquarks at the TeV scale. We consider an effective description, with leptoquarks arising as composite pseudo Nambu-Goldstone bosons, as well as anarchic partial compositeness of the SM fermions. Considering the $R_K^{(\ast )}$ anomaly within this framework, we study pair production of $S_3\sim (\bar{3},3{)}_{1/3}$ at the LHC. We focus on the component $S_3^{1/3}$ of the triplet, which decays predominantly into $t\tau$ and $b\nu$, and study the bounds from existing searches at $\sqrt{s}=13$ TeV at the LHC. We find that sbottom searches in the $b\bar{b}$+MET final state best explore the region in parameter space preferred by our model and currently exclude $S_3^{1/3}$ masses up to $\sim$1 TeV. Additional searches, considering the $t\tau$ and $t\mu$ decay modes, are required to probe the full physical parameter space. In this paper we also recast existing studies on direct leptoquark searches in the $t\tau t\tau$ channel and SM $t\bar{t}t\bar{t}$ searches, and obtain the regions in parameter space currently excluded. Practically the whole physical parameter space is currently excluded for masses up to $\sim$0.8 TeV, which could be extended up to $\sim$1 TeV with the full Run 3 dataset. We conclude that pair production searches for this leptoquark can benefit from considering the final state $t\tau b$ +MET, where the largest branching ratio is expected. We appraise that future explorations of leptoquarks explaining the B-anomalies with masses beyond the TeV should also consider single and non-resonant production in order to extend the mass reach.

   hep-phJHEP(2018)·18 citations
2. 02*

   Spontaneous CP Violation and the Strong CP Problem in Left-Right Symmetric Theories

   Sebastian Ohmer🇩🇪

   We study spontaneous CP violation as a solution to the strong CP problem in left-right symmetric theories. The discrete CP symmetry is broken by a complex vacuum expectation value of a right-handed Higgs doublet. Heavy vectorlike down-type quarks mix with the Standard Model quarks introducing the known CP violation - realizing a variant of the Nelson-Barr mechanism. A nonvanishing QCD vacuum angle is generated at loop level. The implementation in the ultraviolet complete theory of trinification at low scales is discussed. We further comment on the phenomenology and future testability of the model.

   hep-phPRD(2019)·3 citations
3. 03*

   Impact of unitarization on the $J/\psi$-light meson cross section

   L. M. Abreu🇧🇷 · E. Cavalcanti🇧🇷 · A. P. C. Malbouisson🇧🇷

   Hidden charm mesons continue playing an essential role as relevant probes to understand the evolution of partonic matter. It is expected that the charmonia that survived the quark-gluon plasma phase suffer collisions with other particles composing the hadronic matter. In this work, we intend to contribute on this subject by presenting an updated study about the interactions of $J/\psi$ with surrounding hadronic medium. The meson-meson interactions are described with a $SU(4)$ effective Lagrangian, and within the framework of unitarized coupled channel amplitudes projected onto s-wave. The symmetry is explicitly broken to $SU(3)$ by suppression of the interactions driven by charmed mesons. We calculate the cross sections for $J/\psi$ scattering by light pseudoscalar mesons ($\pi ,K,\eta$) and vector mesons ($\rho ,K^{\ast },\omega$), as well as their inverse processes. Keeping the validity of this present approach in the low CM energy range, the most relevant channels are evaluated and a comparison of the findings with existing literature is performed.

   hep-phnucl-thNPA(2018)·3 citations
4. 04*

   Holographic $J/\psi$ production near threshold and the proton mass problem

   Yoshitaka Hatta🇯🇵 · Di-Lun Yang🇯🇵

   It has been suggested that the production of a heavy quarkonium near threshold in electron-proton scattering can shed light on the origin of the proton mass via the QCD trace anomaly. We study the photoproduction of $J/\psi$ off the proton using gauge/string duality and demonstrate that the $t$-dependence of the differential cross section $d\sigma /dt$ at small-$t$ is a sensitive probe of the trace anomaly.

   hep-phPRD(2018)·128 citations
5. 05*

   Probing the effects of new physics in ${\bar{B}}^{\ast }\to P\ell {\bar{\nu }}_{\ell }$ decays

   Qin Chang🇨🇳 · Jie Zhu🇨🇳 · Na Wang🇨🇳 · Ru-Min Wang🇨🇳

   The significant divergence between the SM predictions and experimental measurements for the ratios, $R_{D^{(\ast )}}\equiv \mathcal{B}(\bar{B}\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau })/\mathcal{B}(\bar{B}\to D^{(\ast )}{\ell }^{\prime -}{\bar{\nu }}_{{\ell }^{\prime }})$ with $({\ell }^{\prime }=e,\mu )$, implies possible hint of new physics in the flavour sector. In this paper, motivated by the "$R_{D^{(\ast )}}$ puzzle" and abundant $B^{\ast }$ data samples at high-luminosity heavy-flavor experiments in the future, we try to probe possible effects of new physics in the semileptonic ${\bar{B}}_{u,d,s}^{\ast }\to P{\ell }^{-}{\bar{\nu }}_{\ell }$ $(P=D,D_s,\pi ,K)$ decays induced by $b\to (u,c){\ell }^{-}{\bar{\nu }}_{\ell }$ transitions in the model-independent vector and scalar scenarios. Using the spaces of NP parameters obtained by fitting to the data of $R_D$ and $R_{D^{\ast }}$, the NP effects on the observables including branching fraction, ratio $R_P^{\ast }$, lepton spin asymmetry and lepton forward-backward asymmetry are studied in detail. We find that the vector type couplings have large effects on the branching fraction and ratio $R_P^{\ast }$. Meanwhile, the scalar type couplings provide significant contributions to all of the observables. The future measurements of these observables in the ${\bar{B}}^{\ast }\to P{\ell }^{-}{\bar{\nu }}_{\ell }$ decays at the LHCb and Belle-II could provide a way to crosscheck the various NP solutions to the "$R_{D^{(\ast )}}$ puzzle".

   hep-phAdv.High Energy Phys.(2018)·26 citations
6. 06*

   Interference effects in reactor antineutrino oscillations

   Zhi-zhong Xing🇨🇳

   We reformulate the probabilities of disappearance neutrino or antineutrino oscillations so as to single out the interference term proportional to the product of \sin[\Delta m^2_{21} L/(4 E)] and \sin[(\Delta m^2_{31} + \Delta m^2_{32}) L/(4 E)], which is transparently sensitive to the neutrino mass ordering. We elaborate this issue for a reactor-based antineutrino oscillation experiment like JUNO, and take account of terrestrial matter effects. If a light sterile neutrino species contributes to P(\overline{\nu}_e \to \overline{\nu}_e), we find that there will be a new interference term proportional to the product of \sin^2 2\theta_{14}, \sin[\Delta m^2_{21} L/(4 E)] and \sin[(\Delta m^2_{41} + \Delta m^2_{42}) L/ (4 E)] in the standard parametrization of the (3+1) X (3+1) active-sterile neutrino mixing matrix.

   hep-ph4 citations
7. 07*

   An $S_3$ flavored left-right symmetric model of quarks

   Dipankar Das🇮🇳 · Palash B. Pal🇮🇳

   We construct a model based on the electroweak gauge group $\mathrm{SU}(2{)}_{\mathrm{L}}\times \mathrm{SU}(2{)}_{\mathrm{R}}\times \mathrm{U}(1{)}_{\mathrm{B}-\mathrm{L}}$ augmented by an $S_3$ symmetry. We assign nontrivial $S_3$ transformation properties to the quarks and consequently we need two scalar bidoublets. Despite the extra bidoublet we have only six Yukawa couplings thanks to the discrete symmetry. Diagonalization of the quark mass matrices shows that at the leading order only the first two generations mix, resulting in a block diagonal CKM matrix, and the first generation quarks are massless. Inclusion of subleading terms produce an acceptable CKM matrix up to corrections of order ${\lambda }^4$. As for the first generation quark masses, we obtain satisfactory value of $m_u/m_d$. The masses themselves, though being in the same ballpark, turn out to be somewhat smaller than the accepted range.

   hep-phPRD(2018)·10 citations
8. 08*

   About Double Parton Scattering at Short Relative Transverse Distances

   Daniele Treleani🇮🇹 · Giorgio Calucci🇮🇹

   By working out the kinematics of double parton scattering at short relative transverse distances, we obtain an explicit link between the transverse centres of mass, of the two hard partonic interactions, and the contributions to the process, due to pairs of interacting partons generated by perturbative splitting. One my thus foresee the interesting possibility of discriminating experimentally between contributions to the double parton scattering cross section, due to interacting parton pairs originated by independent evolution, and contributions, due to interacting parton pairs generated by splitting.

   hep-ph5 citations
9. 09*

   Witten's loop in the minimal flipped $SU(5)$ unification revisited

   Dylan Harries🇦🇺 · Michal Malinský🇨🇿 · Martin Zdráhal🇨🇿

   In the simplest potentially realistic renormalizable variants of the flipped $SU(5)$ unified model the right-handed neutrino masses are conveniently generated by means of the Witten's two-loop mechanism. As a consequence, the compactness of the underlying scalar sector provides strong correlations between the low-energy flavor observables such as neutrino masses and mixing and the flavor structure of the fermionic currents governing the baryon and lepton number violating nucleon decays. In this study, the associated two-loop Feynman integrals are fully evaluated and, subsequently, are used to draw quantitative conclusions about the central observables of interest such as the proton decay branching ratios and the absolute neutrino mass scale.

   hep-phPRD(2018)·5 citations
10. 10*

    Unintegrated gluon distribution from forward polarized $\rho$-electroproduction

    Andrèe Dafne Bolognino🇮🇹 · Francesco Giovanni Celiberto🇪🇸 · Dmitry Yu. Ivanov🇷🇺 · Alessandro Papa🇮🇹

    We present here some arguments to support our suggestion that data on the helicity structure for the hard exclusive electroproduction of $\rho$ mesons at HERA (and in possible future high-energy electron-proton colliders) provide useful information to constrain the $\kappa$-shape of the unintegrated gluon distribution in the proton.

    hep-phEPJC(2018)·109 citations
11. 11*

    Muon $g-2$ in a $U(1)$-symmetric Two-Higgs-Doublet Model

    Shao-Ping Li🇨🇳 · Xin-Qiang Li🇨🇳 · Ya-Dong Yang🇨🇳

    We show in this paper that, in a $U(1)$-symmetric two-Higgs-doublet model (2HDM), the two additional neutral Higgs bosons would become nearly degenerate in the large $\tan \beta$ regime, under the combined constraints from both theoretical arguments and experimental measurements. As a consequence, the excess observed in the anomalous magnetic moment of the muon could not be addressed in the considered framework, following the usual argument where these two neutral scalars are required to manifest a large mass hierarchy. On the other hand, we find that, with an $\mathcal{O}(1)$ top-Yukawa coupling and a relatively light charged Higgs boson, large contributions from the two-loop Barr-Zee type diagrams can account for the muon $g-2$ anomaly at the 1$\sigma$ level, in spite of a large cancellation between the scalar and pseudoscalar contributions. Furthermore, the same scenario can survive the tight constraints from the $B$-physics observables.

    hep-phhep-exPRD(2019)·33 citations
12. 12*

    Dimuon resonance near 28 GeV and muon anomaly

    S.I. Godunov🇷🇺 · V.A. Novikov🇷🇺 · M.I. Vysotsky🇷🇺 · E.V. Zhemchugov🇷🇺

    We discuss if the resonance recently observed by CMS can be responsible for the deviation of the experimentally measured muon anomalous magnetic moment from the theoretical prediction.

    hep-phhep-exJETP Lett.(2019)·11 citations
13. 13*

    Semileptonic $B$ and $B_s$ decays involving scalar and axial-vector mesons

    Xian-Wei Kang🇨🇳 · Tao Luo🇨🇳 · Yi Zhang🇨🇳 · Ling-Yun Dai🇨🇳 · Chao Wang🇨🇳

    We report our theoretical calculations on the branching fractions for the semileptonic $B$ and $B_s$ decays, i.e., $B(B_s)\to (P,V,S,A)\ell {\nu }_{\ell }$, where $P$ and $V$ denote the pseudoscalar and vector mesons, respectively, while $S$ denotes the scalar meson with mass above 1 GeV and $A$ the axial-vector meson. The branching fractions for the semileptonic $B\to P$ and $V$ modes have been measured very well in experiment and our theoretical values are in good agreement with them. The ones for $B\to S$ and $A$ modes are our theoretical predictions. There is little experimental information on the semileptonic $B_s$ decays although much theoretical effort has been done. In addition, we predict the branching fractions of $B\to D_0^{\ast }(2400)\ell {\bar{\nu }}_{\ell }$ and $B_s\to D_{s0}^{\ast -}(2317)\ell {\bar{\nu }}_{\ell }$ as $(2.31\pm 0.25)\times 10^{-3}$ and $(3.07\pm 0.34)\times 10^{-3}$, in order, assuming them as the conventional mesons with quark-antiquark configuration. The high luminosity $e^{+}{e}^{-}$ collider SuperKEKB/Belle-II is running, with the data sample enhanced by a factor of 40 compared to Belle, which will provide huge opportunity for the test of the theoretical predictions and further help understand the inner structure of these scalar and axial vector mesons, e.g., the glueball content of $f_0(1710)$ and the mixing angles for the axial-vector mesons. These decay channels can also be accessed by the LHCb experiment.

    hep-phEPJC(2018)·41 citations
14. 14*

    Neutrinophilic Dark Matter in the epoch of IceCube and Fermi-LAT

    Marco Chianese🇬🇧 · Gennaro Miele🇮🇹 · Stefano Morisi🇮🇹 · Eduardo Peinado🇲🇽

    The recent observation of the blazar TXS 0506+056 suggests the presence of a hard power-law component in the extraterrestrial TeV-PeV neutrino flux, in agreement with the IceCube analysis on the 8-year through-going muon neutrinos from the Northern Sky. This is slightly in tension with the soft power-law neutrino flux deduced by the IceCube 6-year High Energy Starting Events data. A possible solution to such a puzzle is assuming a two-component neutrino flux. In this paper, we focus on the case where, in addition to an astrophysical power-law, the second component is a pure neutrino line produced by decaying Dark Matter particles. We investigate how to realize a neutrinophilic decaying Dark Matter in an extension of the Standard Model. The main features of the model are: i) the requirement of a new symmetry like a global $U(1)$ charge; ii) the Dirac nature of active neutrinos; iii) a low-reheating temperature of the Universe of about 1 TeV. We perform a likelihood statistical analysis to fit the IceCube data according to the present Fermi-LAT gamma-rays constraints.

    hep-phJCAP(2018)·19 citations
15. 15*

    A class of the NSVZ renormalization schemes for $\mathcal{N}=1$ SQED

    I.O.Goriachuk🇷🇺 · A.L.Kataev🇷🇺 · K.V.Stepanyantz🇷🇺

    For the $\mathcal{N}=1$ supersymmetric electrodynamics we investigate renormalization schemes in which the NSVZ equation relating the $\beta$-function to the anomalous dimension of the matter superfields is valid in all loops. We demonstrate that there is an infinite set of such schemes. They are related by finite renormalizations which form a group and are parameterized by one finite function and one arbitrary constant. This implies that the NSVZ $\beta$-function remains unbroken if the finite renormalization of the coupling constant is related to the finite renormalization of the matter superfields by a special equation derived in this paper. The arbitrary constant corresponds to the arbitrariness of choosing the renormalization point. The results are illustrated by explicit calculations in the three-loop approximation.

    ↳ hep-thhep-phPLB(2018)·33 citations
16. 16*

    Gluon Quasi-PDF From Lattice QCD

    Zhou-You Fan🇺🇸 · Yi-Bo Yang🇺🇸 · Adam Anthony🇺🇸 · Huey-Wen Lin🇺🇸 · Keh-Fei Liu🇺🇸

    We present the first attempt to access the $x$-dependence of the gluon unpolarized parton distribution function (PDF), based on lattice simulations using the large-momentum effective theory (LaMET) approach. The lattice calculation is carried out with pion masses of 340 and 678 MeV on a 2+1-flavor DWF configuration with lattice spacing $a=0.111$~fm, for the gluon quasi-PDF matrix element with the nucleon momentum up to 0.93 GeV. Taking the normalization from similar matrix elements in the rest frame of the nucleon and pion, our results for these matrix elements are consistent with the Fourier transform of the global fit CT14 and PDF4LHC15 NNLO of the gluon PDF, within statistical uncertainty and the systematic one up to power corrections, perturbative $\mathcal{O}({\alpha }_s)$ matching and the mixing from the quark PDFs.

    ↳ hep-lathep-phnucl-thPRL(2018)·107 citations
17. 17*

    Scale and confinement phase transitions in scale invariant $SU(N)$ scalar gauge theory

    Jisuke Kubo🇩🇪 · Masatoshi Yamada🇩🇪

    We consider scalegenesis, spontaneous scale symmetry breaking, by the scalar-bilinear condensation in $SU(N)$ scalar gauge theory. In an effective field theory approach to the scalar-bilinear condensation at finite temperature, we include the Polyakov loop to take into account the confinement effect. The theory with $N=3,4,5$ and $6$ is investigated, and we find that in all these cases the scale phase transition is a first-order phase transition. We also calculate the latent heat at and slightly below the critical temperature. Comparing the results with those obtained without the Polyakov loop effect, we find that the Polyakov effect can considerably increase the latent heat in some cases, which would mean a large increase in the energy density of the gravitational waves background, if it were produced by the scale phase transition.

    ↳ hep-thhep-phJHEP(2018)·14 citations
18. 18*

    From Scattering Amplitudes to Classical Potentials in the Post-Minkowskian Expansion

    Clifford Cheung🇺🇸 · Ira Z. Rothstein🇺🇸 · Mikhail P. Solon🇺🇸

    We combine tools from effective field theory and generalized unitarity to construct a map between on-shell scattering amplitudes and the classical potential for interacting spinless particles. For general relativity, we obtain analytic expressions for the classical potential of a binary black hole system at second order in the gravitational constant and all orders in velocity. Our results exactly match all known results up to fourth post-Newtonian order, and offer a simple check of future higher order calculations. By design, these methods should extend to higher orders in perturbation theory.

    ↳ hep-thgr-qchep-phPRL(2018)·514 citations
19. 19*

    Extraction of $\gamma n\to \pi N$ observables from deuteron-target data

    Satoshi X. Nakamura (Universidade Cruzeiro do Sul)🇧🇷

    An examination is conducted on a commonly used procedure for extracting (un)polarized $\gamma n\to {\pi }^{-}p$ and $\gamma n\to {\pi }^{0}n$ observables from $d(\gamma ,{\pi }^{-})pp$ and $d(\gamma ,{\pi }^0)pn$ data, using a model that consists of the impulse term and the final-state interaction (FSI) terms due to nucleon- and pion-exchange. Recent experimental and theoretical analyses used an extraction method that does not impose a cut on the final $\pi N$ invariant mass $W$. I demonstrate that the use of this method can result in the $\gamma n\to \pi N$ observables that are seriously distorted by the nucleon Fermi motion, and that one can efficiently avoid this problem by imposing a cut on $W$. It is also shown that the use of kinematical cuts of recent experimental analyses can still leave in the selected samples substantial FSI effects that must be corrected in extracting the $\gamma n\to \pi N$ cross sections. In terms of the nucleon- and pion-exchange mechanisms, I give the first qualitative explanation of the FSI corrections, obtained in a recent MAMI experiment, for extracting $\gamma n\to {\pi }^{0}n$ cross sections.

    ↳ nucl-thhep-phnucl-exPRC(2018)·14 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.