Mon·Nov 30, 2015Monday·November 30, 2015

1. 01*

   A resolution of the puzzle of low V_us values from inclusive flavor-breaking sum rule analyses of hadronic tau decay

   R.J. Hudspith🇨🇦 · R. Lewis🇨🇦 · K. Maltman🇨🇦 · C.E. Wolfe🇨🇦 · J. Zanotti🇦🇺

   Continuum and lattice methods are used to investigate systematic issues in the sum rule determination of $V_{us}$ using inclusive hadronic $\tau$ decay data. Results for $V_{us}$ employing assumptions for $D>4$ OPE contributions used in previous conventional implementations of this approach are shown to display unphysical dependence on the sum rule weight, $w$, and choice of upper limit, $s_0$, of the relevant experimental spectral integrals. Continuum and lattice results suggest a new implementation of the sum rule approach with not just $|V_{us}|$, but also $D>4$ effective condensates, fit to data. Lattice results are also shown to provide a quantitative assessment of truncation uncertainties for the slowly converging $D=2$ OPE series. The new sum rule implementation yields $|V_{us}|$ results free of unphysical $s_0$- and $w$-dependences and $\sim 0.0020$ higher than that obtained using the conventional implementation. With preliminary new experimental results for the $K\pi$ branching fraction, the resulting $|V_{us}|$ is in excellent agreement with that based on $K_{\ell 3}$, and compatible within errors with expectations from three-family unitarity.

   hep-phhep-exhep-latJ.Univ.Sci.Tech.China(2016)·7 citations
2. 02*

   Heavy Tetraquarks in the Diquark-Antidiquark Picture

   M. R. Hadizadeh🇺🇸 · A. Khaledi-Nasab🇺🇸

   The homogeneous Lippmann-Schwinger integral equation is solved in momentum space to calculate the masses of heavy tetraquarks with hidden charm and bottom. The tetraquark bound states are studied in the diquark-antidiquark picture as a two-body problem. A regularized form of the diquark-antidiquark potential is used to overcome the singularity of the confining potential at large distances or small momenta. Our numerical results indicate that the relativistic effect leads to a small reduction in the mass of heavy tetraquarks, which is less than $2\%$ for charm and less than $0.2\%$ for bottom tetraquarks. The calculated masses of heavy tetraquarks for $1s$, $1p$, $2s$, $1d$ and $2p$ states are in good agreement with other theoretical calculations and experimental data. Our numerical analysis predict the masses of heavy tetraquarks for $3s$, $2d$ and $3p$ states for the first time, and we are not aware of any other theoretical results or experimental data for these states.

   hep-phPLB(2016)·20 citations
3. 03*

   $h,Z\to {\ell }_i{\bar{\ell }}_j$, $\Delta a_{\mu }$, $\tau \to (3\mu ,\mu \gamma )$ in generic two-Higgs-doublet models

   R. Benbrik🇲🇦 · Chuan-Hung Chen🇹🇼 · Takaaki Nomura🇰🇷

   Inspired by a significance of $2.4\sigma$ in $h\to \mu \tau$ decay observed by CMS at $\sqrt{s}=8$ TeV, we investigate the Higgs lepton flavor violating effects in the generic two-Higgs-doublet model (GTHDM), where the lepton flavor changing neutral currents are induced at tree level and arisen from Yukawa sector. We revisit the constraints for GTHDM by considering theoretical requirements, precision measurements of $\delta \rho$ and oblique parameters $S$, $T$, $U$ and Higgs measurements. The bounds from Higgs data now play the major role. With the values of parameters that simultaneously satisfy the Higgs bounds and the excess of Higgs coupling to $\mu$-$\tau$ at CMS, we find that the tree-level $\tau \to 3\mu$ and loop-induced $\tau \to \mu \gamma$ could be consistent with current experimental upper limits; the discrepancy in muon $g-2$ between experiment and standard model prediction could be solved; and an interesting relation between muon $g-2$ and branching ratio (BR) for $\mu \to e\gamma$ is found. The GTHM results that the ratio $BR(h\to e\tau )/BR(h\to \mu \tau )$ should be smaller than $10^{-4}$ in order of magnitude. Additionally, we also study the rare decay $Z\to \mu \tau$ and get $BR(Z\to \mu \tau )<10^{-6}$.

   hep-phhep-exPRD(2016)·52 citations
4. 04*

   Heavy baryons with Strangeness in Soliton Models

   H. Weigel🇿🇦 · J.P. Blanckenberg🇿🇦

   We present some recent results from soliton model calculations for the spectrum of baryons with a single heavy quark.The model comprises chiral symmetry for light flavors and (approximate) heavy spin-flavor symmetry for the heavy quarks. We focus on flavor symmetry breaking for strangeness degrees of freedom.

   hep-phnucl-thInt.J.Mod.Phys.Conf.Ser.(2015)·0 citations
5. 05*

   Magnetic moments of JP = 3/2+ decuplet baryons using statistical model

   Amanpreet Kaur🇮🇳 · Alka Upadhyay🇮🇳

   A suitable wave function for baryon decuplet is framed with inclusion of sea containing quark- gluon Fock states. Relevant operator formalism is applied to calculate magnetic moments of JP = 3 2 + baryon decuplet. Statistical model assumes decomposition of baryonic state in various quark-gluon Fock states such as jqqqijgi; jqqqijggi; jqqqijgggi with possibility gluon emitting qq pairs condensates due to the subprocesses like g , qq; g , gg and g , qg where qq = uu; dd; ss. Statistical approach and detailed balance principle in combination is used to find the relative probabilities of these Fock states in avor, spin and color space. The total number of partons (sea) in this formalism are restricted to three gluons due to limited free energy of gluon and suppressed number of strange quark-antiquark pairs. The combined approach is used to calculate the magnetic moments, importance of strangeness in the sea (scalar, vector and tensor). Our approach has confirmed the scalar-tensor sea dominancy over vector sea. Various modifications in the model are used to check the validity of statistical approach. The results are matched with theoretical data available. Good consistency with the experimental data have been achieved for Delta++, Delta+ and Omega-.

   hep-phEPJA(2016)·14 citations
6. 06*

   Pion Induced Reactions for the Study of Charmed Baryons

   Sang-Ho Kim🇰🇷 · Atsushi Hosaka🇯🇵 · Hyun-Chul Kim🇰🇷 · Hiroyuki Noumi🇯🇵

   In this talk, we report the study of ${\pi }^{-}p\to K^{\ast 0}\Lambda$ and ${\pi }^{-}p\to D^{\ast -}{\Lambda }_c^{+}$ reactions by using an effective Lagrangian method and a hybrid Regge model. The total and differential cross sections for the $K^{\ast 0}\Lambda$ production are first calculated and then those for the $D^{\ast -}{\Lambda }_c^{+}$ one are estimated. The two models yield different results, each exhibiting specific features. Our prediction for the charm production provides valuable information about the upcoming J-PARC experiment.

   hep-phhep-exnucl-exnucl-thJPS Conf.Proc.(2016)·1 citation
7. 07*

   Generalized threshold resummation in inclusive DIS and semi-inclusive electron-positron annihilation

   A.A. Almasy (DESY, Zeuthen)🇩🇪 · N.A. Lo Presti (Zurich U.)🇨🇭 · A. Vogt (Liverpool U., Dept. Math.)🇬🇧

   We present analytic all-order results for the highest three threshold logarithms of the space-like and time-like off-diagonal splitting functions and the corresponding coefficient functions for inclusive deep-inelastic scattering (DIS) and semi-inclusive e^+ e^- annihilation. All these results, obtained through an order-by-order analysis of the structure of the corresponding unfactorized quantities in dimensional regularization, can be expressed in terms of the Bernoulli functions introduced by one of us and leading-logarithmic soft-gluon exponentials. The resulting numerical corrections are small for the splitting functions but large for the coefficient functions. In both cases more terms in the threshold expansion need to be determined in order to arrive at quantitatively reliable results.

   hep-phJHEP(2016)·23 citations
8. 08*

   QCD corrections to $W^{+}{W}^{-}$ production through gluon fusion

   Fabrizio Caola🇨🇭 · Kirill Melnikov🇩🇪 · Raoul Röntsch🇩🇪 · Lorenzo Tancredi🇩🇪

   We compute the next-to-leading order (NLO) QCD corrections to the $gg\to W^{+}{W}^{-}\to l_1^{+}{\nu }_1{l}_2^{-}{\bar{\nu }}_2$ process, mediated by a massless quark loop, at the LHC. This process first contributes to the hadroproduction of $W^{+}{W}^{-}$ at $\mathcal{O}({\alpha }_s^2)$, but, nevertheless, has a sizable impact on the total production rate. We find that the NLO QCD corrections to the $gg\to W^{+}{W}^{-}$ process amount to $\mathcal{O}(50)$%, and increase the NNLO QCD cross sections of $pp\to W^{+}{W}^{-}$ by approximately two percent, at both the 8 TeV and 13 TeV LHC. We also compute the NLO corrections to gluonic $W^{+}{W}^{-}$ production within a fiducial volume used by the ATLAS collaboration in their 8 TeV measurement of the $W^{+}{W}^{-}$ production rate and find that the QCD corrections are significantly smaller than in the inclusive case. While the current experimental uncertainties are still too large to make these differences relevant, the observed strong dependence of perturbative corrections on kinematic cuts underscores that extrapolation from a fiducial measurement to the total cross section is an extremely delicate matter, and calls for the direct comparison of fiducial volume measurements with corresponding theoretical computations.

   hep-phhep-exPLB(2016)·184 citations
9. 09*

   Jet substructures of boosted polarized hadronic tops

   Yoshio Kitadono🇹🇼 · Hsiang-nan Li🇹🇼

   We study jet substructures of a boosted polarized top quark, which undergoes the hadronic decay $t\to bu\bar{d}$, in the perturbative QCD framework, focusing on the energy profile and the differential energy profile. These substructures are factorized into the convolution of a hard top-quark decay kernel with a bottom-quark jet function and a $W$-boson jet function, where the latter is further factorized into the convolution of a hard $W$-boson decay kernel with two light-quark jet functions. Computing the hard kernels to leading order in QCD and including the resummation effect in the jet functions, we show that the differential jet energy profile is a useful observable for differentiating the helicity of a boosted hadronic top quark: a right-handed top jet exhibits quick descent of the differential energy profile with the inner test cone radius $r$, which is attributed to the $\text{mbox}V-A$ structure of weak interaction and the dead-cone effect associated with the $W$-boson jet. The above helicity differentiation may help to reveal the chiral structure of physics beyond the Standard Model at high energies.

   hep-phPRD(2016)·9 citations
10. 10*

    NLO QCD+EW predictions for V+jets including off-shell vector-boson decays and multijet merging

    Stefan Kallweit🇩🇪 · Jonas M. Lindert🇨🇭 · Stefano Pozzorini🇨🇭 · Marek Schönherr🇨🇭 · Philipp Maierhöfer🇩🇪

    We present next-to-leading order (NLO) predictions including QCD and electroweak (EW) corrections for the production and decay of off-shell electroweak vector bosons in association with up to two jets at the 13 TeV LHC. All possible dilepton final states with zero, one or two charged leptons that can arise from off-shell W and Z bosons or photons are considered. All predictions are obtained using the automated implementation of NLO QCD+EW corrections in the OpenLoops matrix-element generator combined with the Munich and Sherpa Monte Carlo frameworks. Electroweak corrections play an especially important role in the context of BSM searches, due to the presence of large EW Sudakov logarithms at the TeV scale. In this kinematic regime, important observables such as the jet transverse momentum or the total transverse energy are strongly sensitive to multijet emissions. As a result, fixed-order NLO QCD+EW predictions are plagued by huge QCD corrections and poor theoretical precision. To remedy this problem we present an approximate method that allows for a simple and reliable implementation of NLO EW corrections in the MEPS@NLO multijet merging framework. Using this general approach we present an inclusive simulation of vector-boson production in association with jets that guarantees NLO QCD+EW accuracy in all phase space regions involving up to two resolved jets.

    hep-phhep-exJHEP(2016)·305 citations
11. 11*

    Modulation and diurnal variation in axionic dark matter searches

    Y. Semertzidis (Center for Axion and Precision Physics Research, IBS, Daejeon, Republic of Korea)🇰🇷 · J.D. Vergados (Centre for the Subatomic Structure of Matter (CSSM), University of Adelaide)🇦🇺

    In the present work we study possible time dependent effects in Axion Dark Matter searches employing resonant cavities. We find that the width of the resonance, which depends on the axion mean square velocity in the local frame, will show an annual variation due to the motion of the Earth around the sun (modulation). Furthermore, if the experiments become directional, employing suitable resonant cavities, one expects large asymmetries in the observed widths relative to the sun's direction of motion. Due to the rotation of the Earth around its axis, these asymmetries will manifest themselves as a diurnal variation in the observed width.

    ↳ astro-ph.GAhep-phPoS(2015)·1 citation
12. 12*

    Non-parametric determination of H and He interstellar fluxes from cosmic-ray data

    A. Ghelfi🇫🇷 · F. Barao🇵🇹 · L. Derome🇫🇷 · D. Maurin🇫🇷

    Top-of-atmosphere (TOA) cosmic-ray (CR) fluxes from satellites and balloon-borne experiments are snapshots of the solar activity imprinted on the interstellar (IS) fluxes. Given a series of snapshots, the unknown IS flux shape and the level of modulation (for each snapshot) can be recovered. We wish (i) to provide the most accurate determination of the IS H and He fluxes from TOA data alone, (ii) to obtain the associated modulation levels (and uncertainties) while fully accounting for the correlations with the IS flux uncertainties, and (iii) to inspect whether the minimal force-field approximation is sufficient to explain all the data at hand. Using H and He TOA measurements, including the recent high-precision AMS, BESS-Polar, and PAMELA data, we performed a non-parametric fit of the IS fluxes $J_{\mathrm{H},\mathrm{He}}^{\mathrm{IS}}$ and modulation level ${\varphi }_i$ for each data-taking period. We relied on a Markov chain Monte Carlo (MCMC) engine to extract the probability density function and correlations (hence the credible intervals) of the sought parameters. Although H and He are the most abundant and best measured CR species, several datasets had to be excluded from the analysis because of inconsistencies with other measurements. From the subset of data passing our consistency cut, we provide ready-to-use best-fit and credible intervals for the H and He IS fluxes from MeV/n to PeV/n energy (with a relative precision in the range [2-10\%] at 1$\sigma$). Given the strong correlation between $J^{\mathrm{IS}}$ and ${\varphi }_i$ parameters, the uncertainties on $J^{\mathrm{IS}}$ translate into $\Delta \varphi \approx \pm 30$~MV (at 1$\sigma$) for all experiments. We also find that the presence of ${}^3$He in He data biases $\varphi$ towards higher $\varphi$ values by $\sim 30$~MV. The force-field approximation gives an excellent (${\chi }^2/$dof$=1.02$) description of the recent high-precision TOA H and He fluxes.

    ↳ astro-ph.HEhep-phAstron.Astrophys.(2016)·60 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.