Thu·Dec 29, 2016Thursday·December 29, 2016

1. 01*

   Subtracting IR Renormalons from Wilson Coefficients: Uniqueness and power dependences on ${\Lambda }_{\mathrm{QCD}}$

   Go Mishima🇯🇵 · Yukinari Sumino🇯🇵 · Hiromasa Takaura🇯🇵

   In the context of OPE and using the large-${\beta }_0$ approximation, we propose a method to define Wilson coefficients free from uncertainties due to IR renormalons. We first introduce a general observable $X(Q^2)$ with an explicit IR cutoff, and then we extract a genuine UV contribution $X_{\mathrm{UV}}$ as a cutoff-independent part. $X_{\mathrm{UV}}$ includes power corrections $\sim ({\Lambda }_{\mathrm{QCD}}^2/Q^2{)}^n$ which are independent of renormalons. Using the integration-by-regions method, we observe that $X_{\mathrm{UV}}$ coincides with the leading Wilson coefficient in OPE and also clarify that the power corrections originate from UV region. We examine scheme dependence of $X_{\mathrm{UV}}$ and single out a specific scheme favorable in terms of analytical properties. Our method would be optimal with respect to systematicity, analyticity and stability. We test our formulation with the examples of the Adler function, QCD force between $Q\bar{Q}$, and $R$-ratio in $e^{+}{e}^{-}$ collision.

   hep-phhep-thnucl-thPRD(2017)·11 citations
2. 02*

   On Naturalness in type II seesaw models and the heavy Higgs masses

   Mohamed Chabab🇲🇦 · Michel Capdequi Peyranere🇫🇷 · Larbi Rahili🇲🇦

   Here we study naturalness problem in a type II seesaw model, and show that the Veltman condition modified (mVC) by virtue of the additional scalar charged states is satisfied at one loop within a region of the allowed parameter space of the model. The latter is severely constrained by unitarity and boundedness from below as well as by consistency with the diphoton Higgs decay data of the LHC run 1. In this context, our analysis of the naturalness condition affects dramatically the masses of heavy Higgs bosons $H^0$, $A^0$, $H^{\pm }$ and $H^{\pm \pm }$, reducing the ranges of variation of $m_{H^{\pm }}$ and $m_{H^{\pm \pm }}$ with an upper bounds at 288 and 351 GeV, respectively, while the neutral Higgs bosons $H^0$, $A^0$ are found to be almost degenerate at about 207 GeV.

   hep-phPoS(2016)·2 citations
3. 03*

   The production of neutral $N^{\ast }(11052)$ resonance with hidden beauty from ${\pi }^{-}p$ scattering

   Chen Cheng🇨🇳 · Xiao-Yun Wang🇨🇳

   We investigate the discovery potential of the predicted neutral hidden beauty $N^{\ast }(11052)$ resonance through ${\pi }^{-}p$ scattering within an effective Lagrangian approach. Two reactions ${\pi }^{-}p\to K^{-}{\Sigma }^{+}$ and ${\pi }^{-}p\to {\eta }_{b}n$ are studied in this work, with nucleon pole exchange as the background. It is found that the contributions of the $N^{\ast }(11052)$ resonance give clear peak structures in the magnitude of 1 $\mu b$ near the threshold of the $N^{\ast }(11052)$ in the total cross sections. The numerical results indicate that the center of mass energy $W\simeq$ 11-11.1 GeV would be a best energy window for searching the $N^{\ast }(11052)$ resonance, where the $N^{\ast }(11052)$ signal can be easily distinguished from the background. The COMPASS experiment at CERN's Super Proton Synchrotron (SPS) with pion beam of $\simeq$ 280 GeV will be an ideal platform for searching the super-heavy resonance with hidden beauty, which is hopeful to test the theoretical results.

   hep-phAdv.High Energy Phys.(2017)·9 citations
4. 04*

   Revisiting Kaon Physics in General $Z$ Scenario

   Motoi Endo🇯🇵 · Teppei Kitahara🇩🇪 · Satoshi Mishima🇯🇵 · Kei Yamamoto🇯🇵

   New physics contributions to the $Z$ penguin are revisited in the light of the recently-reported discrepancy of the direct CP violation in $K\to \pi \pi$. Interference effects between the standard model and new physics contributions to $\Delta S=2$ observables are taken into account. Although the effects are overlooked in the literature, they make experimental bounds significantly severer. It is shown that the new physics contributions must be tuned to enhance $\mathcal{B}(K_L\to {\pi }^0\nu \bar{\nu })$, if the discrepancy of the direct CP violation is explained with satisfying the experimental constraints. The branching ratio can be as large as $6\times 10^{-10}$ when the contributions are tuned at the 10 % level.

   hep-phhep-exPLB(2017)·58 citations
5. 05*

   Stretching and Kibble scaling regimes for Hubble-damped defect networks

   C. J. A. P. Martins🇵🇹 · I. Yu. Rybak🇵🇹 · A. Avgoustidis🇬🇧 · E. P. S. Shellard🇬🇧

   The cosmological evolution of topological defect networks can broadly be divided into two stages. At early times they are friction-dominated due to particle scattering and therefore non-relativistic, and may either be conformally stretched or evolve in the Kibble regime. At late times they are relativistic and evolve in the well known linear scaling regime. In this work we show that a sufficiently large Hubble damping (that is a sufficiently fast expansion rate) leads to a linear scaling regime where the network is non-relativistic. This is therefore another realization of a Kibble scaling regime, and also has a conformal stretching regime counterpart which we characterize for the first time. We describe these regimes using analytic arguments in the context of the velocity-dependent one-scale model, and we confirm them using high-resolution $4096^3$ field theory simulations of domain wall networks. We also use these simulations to improve the calibration of this analytic model for the case of domain walls.

   hep-phastro-ph.COgr-qchep-thPRD(2016)·19 citations
6. 06*

   $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$ Decay in the Aligned Two-Higgs-Doublet Model

   Quan-Yi Hu🇨🇳 · Xin-Qiang Li🇨🇳 · Ya-Dong Yang🇨🇳

   In the aligned two-Higgs-doublet model, we perform a complete one-loop computation of the short-distance Wilson coefficients $C_{7,9,10}^{(\prime )}$, which are the most relevant ones for $b\to s{\ell }^{+}{\ell }^{-}$ transitions. It is found that, when the model parameter $\left|{\varsigma }_u\right|$ is much smaller than $\left|{\varsigma }_d\right|$, the charged-scalar contributes mainly to chirality-flipped $C_{9,10}^{\prime }$, with the corresponding effects being proportional to ${\left|{\varsigma }_d\right|}^2$. Numerically, the charged-scalar effects fit into two categories: (A) $C_{7,9,10}^{{\mathrm{H}}^{\pm }}$ are sizable, but $C_{9,10}^{\prime {\mathrm{H}}^{\pm }}\simeq 0$, corresponding to the (large $\left|{\varsigma }_u\right|$, small $\left|{\varsigma }_d\right|$) region; (B) $C_7^{{\mathrm{H}}^{\pm }}$ and $C_{9,10}^{\prime {\mathrm{H}}^{\pm }}$ are sizable, but $C_{9,10}^{{\mathrm{H}}^{\pm }}\simeq 0$, corresponding to the (small $\left|{\varsigma }_u\right|$, large $\left|{\varsigma }_d\right|$) region. Taking into account phenomenological constraints from the inclusive radiative decay $B\to X_s\gamma$, as well as the latest model-independent global analysis of $b\to s{\ell }^{+}{\ell }^{-}$ data, we obtain the much restricted parameter space of the model. We then study the impact of the allowed model parameters on the angular observables $P_2$ and $P_5^{\prime }$ of $B^0\to K^{\ast 0}{\mu }^{+}{\mu }^{-}$ decay, and find that $P_5^{\prime }$ could be increased significantly to be consistent with the experimental data in case B.

   hep-phhep-exEPJC(2017)·49 citations
7. 07*

   Minimal Seesaw Model with a Discrete Heavy-Neutrino Exchange Symmetry

   Thomas Rink🇩🇪 · Kai Schmitz🇩🇪 · Tsutomu T. Yanagida🇯🇵

   We present a Froggatt-Nielsen flavor model that yields a minimal realization of the type-I seesaw mechanism. This seesaw model is minimal for three reasons: (i) It features only two rather than three right-handed sterile neutrinos: N_1 and N_2, which form a pair of pseudo-Dirac neutrinos; (ii) the neutrino Yukawa matrix exhibits flavor alignment, i.e., modulo small perturbations, it contains only three independent parameters; and (iii) the N_1,2 coupling to the electron flavor is parametrically suppressed compared to the muon and tau flavors, i.e., the neutrino Yukawa matrix exhibits an approximate two-zero texture. Crucial ingredients of our model are (a) Froggatt-Nielsen flavor charges consistent with the charged-lepton masses as well as (b) an approximate, discrete exchange symmetry that manifests itself as N_1 <--> i N_2 in the heavy-neutrino Yukawa interactions and as N_1 <--> N_2 in the heavy-neutrino mass terms. This model predicts a normal light-neutrino mass hierarchy, a close-to-maximal CP-violating phase in the lepton mixing matrix, \delta~3/2\pi, as well as resonant leptogenesis in accord with arguments from naturalness, vacuum stability, perturbativity and lepton flavor violation.

   hep-ph16 citations
8. 08*

   Alternative dark matter candidates: Axions

   Andreas Ringwald🇩🇪

   The axion is arguably one of the best motivated candidates for dark matter. For a decay constant greater than about 10^9 GeV, axions are dominantly produced non-thermally in the early universe and hence are "cold", their velocity dispersion being small enough to fit to large scale structure. Moreover, such a large decay constant ensures the stability at cosmological time scales and its behaviour as a collisionless fluid at cosmological length scales. Here, we review the state of the art of axion dark matter predictions and of experimental efforts to search for axion dark matter in laboratory experiments.

   hep-phastro-ph.COhep-exPoS(2016)·44 citations
9. 09*

   CMFV models facing the recent progress in lattice calculations of $B_{s,d}$ mixing

   Monika Blanke🇩🇪

   Recent results by the Fermilab Lattice and MILC collaborations on the hadronic matrix elements entering $B_{s,d}-{\bar{B}}_{s,d}$ mixing have reached an unprecedented precision. Interestingly the Standard Model (SM) predictions using these updated values, together with the CKM elements obtained from tree-level decays, exhibit a significant tension with the measured values of the mass differences $\Delta M_s$, $\Delta M_d$ and their ratio. Assessing this tension in a model-independent way, it can be shown that models with Constrained Minimal Flavour Violation can not improve the situation with respect to the SM, in particular when the correlation with the CP-violating parameter ${\epsilon }_K$ is taken into account. The new lattice results, if eventually confirmed by independent calculations, therefore imply the presence of new sources of flavour violation in the $\Delta F=2$ sector.

   hep-phPoS(2016)·1 citation
10. 10*

    Parton Distributions from Lattice QCD with Momentum Smearing

    Constantia Alexandrou🇨🇾 · Krzysztof Cichy🇩🇪 · Martha Constantinou🇺🇸 · Kyriakos Hadjiyiannakou🇨🇾 · Karl Jansen🇩🇪 · Fernanda Steffens🇩🇪 · Christian Wiese🇩🇪

    In this work we continue our effort to explore a recent proposal, which allows light-cone distributions to be extracted from purely spatial correlations, being thus accessible to lattice methods. In order to test the feasibility of this method, we present our latest results from a twisted mass lattice calculation of the flavor non-singlet momentum, helicity and transversity distributions of the nucleon. Furthermore, we apply a newly proposed momentum improved smearing, which has the potential to reach higher nucleon momenta as required for a safe matching procedure to the physical distribution functions.

    ↳ hep-lathep-phPoS(2016)·11 citations
11. 11*

    Constraints on Nonmetricity from Bounds on Lorentz Violation

    Joshua Foster🇺🇸 · Alan Kostelecky🇺🇸 · Rui Xu🇺🇸

    Spacetime nonmetricity can be studied experimentally through its couplings to fermions and photons. We use recent high-precision searches for Lorentz violation to deduce first constraints involving the 40 independent nonmetricity components down to levels of order $10^{-43}$ GeV.

    ↳ gr-qchep-phPRD(2017)·51 citations
12. 12*

    Chiral primordial blue tensor spectra from the axion-gauge couplings

    Ippei Obata🇯🇵

    We suggest the new feature of primordial gravitational waves sourced by the axion-gauge couplings, whose forms are motivated by the dimensional reduction of the form field in the string theory. In our inflationary model, as an inflaton we adopt two types of axion, dubbed the model-independent axion and the model-dependent axion, which couple with two gauge groups with different sign combination each other. Due to these forms both polarization modes of gauge fields are amplified and enhance both helicies of tensor modes during inflation. We point out the possibility that a primordial blue-tilted tensor power spectra with small chirality are provided by the combination of these axion-gauge couplings, intriguingly both amplitudes and chirality are potentially testable by future space-based gravitational wave interferometers such as DECIGO and BBO project.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2017)·32 citations
13. 13*

    Cosmological Constant Problem and Renormalized Vacuum Energy Density in Curved Background

    Kazunori Kohri🇯🇵 · Hiroki Matsui🇯🇵

    The current vacuum energy density observed as dark energy ${\rho }_{\mathrm{dark}}\simeq 2.5\times 10^{-47}\mathrm{Ge}{\mathrm{V}}^4$ is unacceptably small compared with any other scales. Therefore, we encounter serious fine-tuning problem and theoretical difficulty to derive the dark energy. However, the theoretically attractive scenario has been proposed and discussed in literature: In terms of the renormalization-group (RG) running of the cosmological constant, the vacuum energy density can be expressed as ${\rho }_{\mathrm{vacuum}}\simeq m^2{H}^2$ where $m$ is the mass of the scalar field and rather dynamical in curved spacetime. However, there has been no rigorous proof to derive this expression and there are some criticisms about the physical interpretation of the RG running cosmological constant. In the present paper, we revisit the RG running effects of the cosmological constant and investigate the renormalized vacuum energy density in curved spacetime. We demonstrate that the vacuum energy density described by ${\rho }_{\mathrm{vacuum}}\simeq m^2{H}^2$ appears as quantum effects of the curved background rather than the running effects of cosmological constant. Comparing to cosmological observational data, we obtain an upper bound on the mass of the scalar fields to be smaller than the Planck mass, $m\lesssim M_{\mathrm{Pl}}$.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2017)·32 citations
14. 14*

    Scattering and momentum space entanglement

    Gianluca Grignani🇮🇹 · Gordon W. Semenoff🇨🇦

    We derive a formula for the entanglement entropy of two regions in momentum space that is generated by the scattering of weakly interacting scalar particles. We discuss an example where weak interactions entangle momentum scales above and below an infrared cutoff.

    ↳ hep-thhep-phquant-phPLB(2017)·34 citations
15. 15*

    Mesic nuclei with a heavy antiquark

    Yasuhiro Yamaguchi🇮🇹 · Shigehiro Yasui🇯🇵

    The binding system of a hadron and a nucleus is a topic of great interest for investigating the hadron properties. In the heavy-flavor region, the attraction between a $P(=\bar{D},B)$ meson and a nucleon $N$ can appear, where the $PN-P^{\ast }N$ mixing plays an important role in relation to the heavy-quark spin symmetry. The attraction can produce exotic heavy mesic nuclei that are stable against the strong decay. We study an exotic system where the $\bar{D}$ ($B$) meson and nucleus are bound. The meson-nucleus interaction is given by a folding potential with single-channel $PN$ interaction and the nucleon number distribution function. By solving the Schrödinger equations of the heavy meson and the nucleus, we obtain several bound and resonant states for nucleon number $A=16,\dots ,208$. The results indicate the possible existence of exotic mesic nuclei with a heavy antiquark.

    ↳ nucl-thhep-phPTEP(2017)·3 citations
16. 16*

    Holography for Heavy Ions Collisions at LHC and NICA

    I. Ya. Aref'eva🇷🇺

    This is a contribution for the Proceedings of 5th International Conference on New Frontiers in Physics (ICNFP 2016), held at Crete, 6-14 July 2016. Our goal is to obtain phenomenologically reliable insights for the physics of the quark-gluon plasma (QGP) from the holography. I briefly review how in the holographic setup one can describe the QGP formation in heavy ion collisions and how to get quantitatively the main characteristics of the QGP formation -- the total multiplicity and the thermalization time. To fit the experimental form of dependence of total multiplicity on energy, obtained at LHC, we have to deal with a special anisotropic holographic model, related with the Lifshitz-type background. Our conjecture is that this Lifshitz-type background with non-zero chemical potential can be used to describe future data expected from NICA. In particular, we present the results of calculations of the holographic confinement/deconfinement phase transition in the $(\mu ,T)$ (chemical potential, temperature) plane in this anisotropic background and show the dependence of the transition line on the orientation of the quark pair. This dependence leads to a non-sharp character of physical confinement/deconfinement phase in the $(\mu ,T)$-plane. We use the bottom-up soft wall approach incorporating quark confinement deforming factor and vector field providing the non-zero chemical potential. In this model we also estimate the holographic photon production.

    ↳ hep-thhep-phEPJ Web Conf.(2017)·36 citations
17. 17*

    Overview of ALICE results in pp, pA and AA collisions

    R. Schicker (for the ALICE Collaboration)🇩🇪

    The ALICE experiment at the Large Hadron Collider (LHC) at CERN is optimized for recording events in the very large particle multiplicity environment of heavy-ion collisions at LHC energies. The ALICE collaboration has taken data in Pb-Pb collisions in Run I and Run II at nucleon-nucleon center-of-mass energies $\sqrt{s_{\text{NN}}}$ = 2.76 and \mbox{5.02 TeV}, respectively, and in pp collisions at center-of-mass energies $\sqrt{s}$ = 0.9, 2.76, 5.02, 7, 8 and 13 TeV. The asymmetric system p-Pb was measured at a center-of-mass energy $\sqrt{s_{\text{NN}}}$ = 5.02 TeV. Selected physics results from the analysis of these data are presented, and an outline of the ALICE prospects for Run III is given.

    ↳ nucl-exhep-phnucl-thEPJ Web Conf.(2017)·16 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.