Wed·Apr 27, 2016Wednesday·April 27, 2016

1. 01*

   New Physics at the TeV Scale

   Shreyashi Chakdar🇺🇸

   The Standard Model of particle physics is assumed to be a low-energy effective theory with new physics theoretically motivated to be around TeV scale. The dissertation presents theories with new physics beyond the Standard Model at the TeV scale testable in the current High Energy Colliders. The study on leptoquarks gauge bosons in reference to TopSU(5) model in chapter 2 showed that their discovery mass range extends upto 1.5 TeV at 14 TeV LHC with luminosity of 100 $f{b}^{-1}$. On the other hand, in chapter 3 we studied the collider phenomenology of TeV scale mirror fermions in Left-Right Mirror model finding that the reaches for the mirror quarks goes upto $750$ GeV at the $14$ TeV LHC with $300f{b}^{-1}$ luminosity. In chapter 4 we have enlarged the bosonic symmetry to fermi-bose symmetry e.g. supersymmetry and have shown that SUSY with non-universalities in gaugino or scalar masses within high scale SUGRA set up can still be accessible at LHC with 14 TeV. In chapter 5, we performed a study in respect to the $e^{+}{e}^{-}$ collider and find that precise measurements of the higgs boson mass splittings upto $\sim 100$ MeV may be possible with high luminosity in the International Linear Collider (ILC). In chapter 6 we have shown that the experimental data on neutrino masses and mixings are consistent with the proposed 4/5 parameter Dirac neutrino models yielding a solution for the neutrino masses with inverted mass hierarchy and large CP violating phase $\delta$ and thus can be tested experimentally. Chapter 7 incorporates a warm dark matter candidate in context of two Higgs doublet model. The model has several testable consequences at LHC. This dissertation presents an endeavor to study beyond standard model (BSM) physics at the TeV scale with testable signals in the Colliders.

   hep-ph0 citations
2. 02*

   An operator basis for the Standard Model with an added scalar singlet

   Ben Gripaios🇬🇧 · Dave Sutherland🇬🇧

   Motivated by the possible di-gamma resonance at 750 GeV, we present a basis of effective operators for the Standard Model plus a scalar singlet at dimensions 5, 6, and 7. We point out that an earlier list at dimensions 5 and 6 contains two redundant operators at dimension 5.

   hep-phhep-exJHEP(2016)·36 citations
3. 03*

   Supersymmetric Explanation of CP Violation in $K\to \pi \pi$ Decays

   Teppei Kitahara🇩🇪 · Ulrich Nierste🇩🇪 · Paul Tremper🇩🇪

   Recent progress in the determination of hadronic matrix elements has revealed a tension between the measured value of ${ϵ}_K^{\prime }/{ϵ}_K$, which quantifies direct $CP$ violation in $K\to \pi \pi$ decays, and the Standard-Model prediction. The well-understood indirect $CP$ violation encoded in the quantity ${ϵ}_K$ typically precludes large new-physics contributions to ${ϵ}_K^{\prime }/{ϵ}_K$ and challenges such an explanation of the discrepancy. We show that it is possible to cure the ${ϵ}_K^{\prime }/{ϵ}_K$ anomaly in the Minimal Supersymmetric Standard Model with squark masses above 3 TeV without overshooting ${ϵ}_K$. This solution exploits two features of supersymmetry: the possibility of large isospin-breaking contributions (enhancing ${ϵ}_K^{\prime }$) and the Majorana nature of gluinos (permitting a suppression of ${ϵ}_K$). Our solution involves no fine-tuning of $CP$ phases or other parameters.

   hep-phhep-exPRL(2016)·59 citations
4. 04*

   Protophobic Fifth Force Interpretation of the Observed Anomaly in ${}^8$Be Nuclear Transitions

   Jonathan L. Feng🇺🇸 · Bartosz Fornal🇺🇸 · Iftah Galon🇺🇸 · Susan Gardner🇺🇸 · Jordan Smolinsky🇺🇸 · Tim M. P. Tait🇺🇸 · Philip Tanedo🇺🇸

   Recently a 6.8$\sigma$ anomaly has been reported in the opening angle and invariant mass distributions of $e^{+}{e}^{-}$ pairs produced in ${}^8\text{Be}$ nuclear transitions. The data are explained by a 17 MeV vector gauge boson $X$ that is produced in the decay of an excited state to the ground state, ${}^8{\text{Be}}^{\ast }\to {}^8\text{Be}X$, and then decays through $X\to e^{+}{e}^{-}$. The $X$ boson mediates a fifth force with a characteristic range of 12 fm and has milli-charged couplings to up and down quarks and electrons, and a proton coupling that is suppressed relative to neutrons. The protophobic $X$ boson may also alleviate the current 3.6$\sigma$ discrepancy between the predicted and measured values of the muon's anomalous magnetic moment.

   hep-phhep-exnucl-exnucl-thPRL(2016)·301 citations
5. 05*

   High-energy evolution to three loops

   Simon Caron-Huot🇩🇰 · Matti Herranen🇩🇰

   The Balitsky-Kovchegov equation describes the high-energy growth of gauge theory scattering amplitudes as well as nonlinear saturation effects which stop it. We obtain the three-loop corrections to this equation in planar $\mathcal{N}=4$ super Yang-Mills theory. Our method exploits a recently established equivalence with the physics of soft wide-angle radiation, so-called non-global logarithms, and thus yields at the same time the three-loop evolution equation for non-global logarithms. As a by-product of our analysis, we develop a Lorentz-covariant method to subtract infrared and collinear divergences in cross-section calculations in the planar limit. We compare our result in the linear regime with a recent prediction for the so-called Pomeron trajectory, and compare its collinear limit with predictions from the spectrum of twist-two operators.

   hep-phhep-thJHEP(2018)·88 citations
6. 06*

   Dilepton bounds on left-right symmetry at the LHC run II and neutrinoless double beta decay

   Manfred Lindner🇩🇪 · Farinaldo S. Queiroz🇩🇪 · Werner Rodejohann🇩🇪

   In the light of the new 13 TeV dilepton data set with $3.2\mathrm{f}{\mathrm{b}}^{-1}$ integrated luminosity from the ATLAS collaboration, we derive limits on the $Z^{\prime }$ mass in the context of left-right symmetric models and exploit the complementarity with dijet and $lljj$ data, as well as neutrinoless double beta decay. We keep the ratio of the left- and right-handed gauge coupling free in order to take into account different patterns of left-right symmetry breaking. By combining the dielectron and dimuon data we can exclude $Z^{\prime }$ masses below $3$ TeV for $g_R=g_L$, and for $g_R\sim 1$ we rule out masses up to $\sim 4$ TeV. Those comprise the strongest direct bounds on the $Z^{\prime }$ mass from left-right models up to date. We show that in the usual plane of right-handed neutrino and charged gauge boson mass, dilepton data can probe a region of parameter space inaccessible to neutrinoless double beta decay and $lljj$ studies. Lastly, through the mass relation between $W_R$ and $Z^{\prime }$ we present an indirect bound on the lifetime of neutrinoless double beta decay using dilepton data. Our results prove that the often ignored dilepton data in the context of left-right models actually provide important complementary limits.

   hep-phhep-exPLB(2016)·50 citations
7. 07*

   Probing TeV scale Top-Philic Resonances with Boosted Top-Tagging at the High Luminosity LHC

   Jeong Han Kim🇰🇷 · Kyoungchul Kong🇺🇸 · Seung J. Lee🇰🇷 · Gopolang Mohlabeng🇺🇸

   We investigate the discovery potential of singly produced top-philic resonances at the high luminosity (HL) LHC in the four-top final state. Our analysis spans over the fully-hadronic, semi-leptonic, and same-sign dilepton channels where we present concrete search strategies adequate to a boosted kinematic regime and high jet-multiplicity environments. We utilize the Template Overlap Method (TOM) with newly developed template observables for tagging boosted top quarks, a large-radius jet variable $M_J$ and customized b-tagging tactics for background discrimination. Our results show that the same-sign dilepton channel gives the best sensitivity among the considered channels, with an improvement of significance up to 10%-20% when combined with boosted-top tagging. Both the fully-hadronic and semi-leptonic channels yield comparable discovery potential and contribute to further enhancements in the sensitivity by combining all channels. Finally, we show the sensitivity of a top-philic resonance at the LHC and HL-LHC by showing the $2\sigma$ exclusion limit and $5\sigma$ discovery reach, including a combination of all three channels.

   hep-phPRD(2016)·47 citations
8. 08*

   Multi-channel assault on natural supersymmetry at the high luminosity LHC

   Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Michael Savoy🇺🇸 · Xerxes Tata🇺🇸

   Recent clarifications of naturalness in supersymmetry robustly require the presence of four light higgsinos with mass ~100-300 GeV while gluinos and (top)-squarks may lie in the multi-TeV range, possibly out of LHC reach. We project the high luminosity (300-3000 fb^{-1}) reach of LHC14 via gluino cascade decays and via same-sign diboson production. We compare these to the reach for neutralino pair production \tz_1\tz_2 followed by \tz_2\to\tz_1\ell^+\ell^- decay to soft dileptons which recoil against a hard jet. It appears that 3000 fb^{-1} is just about sufficient integrated luminosity to probe naturalness with up to 3\% fine-tuning at the 5-sigma level, thus either discovering natural supersymmetry or else ruling it out.

   hep-phhep-exPRD(2016)·42 citations
9. 09*

   Perturbatively stable observables in heavy-quark leptoproduction

   N.Ya. Ivanov🇦🇲

   We study the perturbative and parametric stability of the QCD predictions for the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ and azimuthal $\cos (2\phi )$ asymmetry, $A(x,Q^2)$, in heavy-quark leptoproduction. We review the available theoretical results for these quantities and conclude that, contrary to the production cross sections, the ratios $R(x,Q^2)$ and $A(x,Q^2)$ are stable under radiative QCD corrections in wide region of the variables $x$ and $Q^2$. This implies that large radiative contributions to the structure functions cancel each other in the ratios $R(x,Q^2)$ and $A(x,Q^2)$ with good accuracy. Then we consider some experimental and phenomenological applications of the observed perturbative stability. We provide compact analytic predictions for $R(x,Q^2)$ and azimuthal $\cos (2\phi )$ asymmetry in the case of low $x\ll 1$. It is demonstrated that our obtained results will be useful in the extraction of the structure functions from measurements of the reduced cross sections. Finally, we analyze the properties of $R(x,Q^2)$ and $A(x,Q^2)$ within the variable-flavor-number scheme (VFNS) of QCD. We conclude that the Callan-Gross ratio and azimuthal asymmetry are perturbatively stable but sensitive to resummation of the mass logarithms of the type ${\alpha }_s\ln \left(Q^2/m^2\right)$. For this reason, the quantities $R(x,Q^2)$ and $A(x,Q^2)$ will be good probes of the heavy-quark content of the proton.

   hep-ph0 citations
10. 10*

    First results on Bilepton production based on LHC collision data and predictions for Run II

    Andre Nepomuceno🇧🇷 · Bernhard Meirose🇺🇸 · Felipe Eccard🇧🇷

    The LHC potential for discovering doubly-charged vector bileptons is investigated considering the measurable process $pp$ $\to$ ${\mu }^{\mp }{\mu }^{\mp }{\mu }^{\pm }{\mu }^{\pm }X$. The study is performed assuming different bilepton and leptoquark masses. The process cross-section is calculated at leading-order using the \textsc{Calchep} package. Combining the calculation with the latest ATLAS experiment results at a center-of-mass energy of 7 TeV, bounds on bilepton masses based on LHC data are derived for the first time. The results exclude bileptons masses in the range of 200 GeV to 500 GeV at 95\% C.L., depending on the leptoquark mass. Moreover, minimal LHC integrated luminosities needed for discovering and for setting limits on bilepton masses are obtained for 13 TeV center-of-mass energy. Simulated events are passed through a fast parametric detector simulation using the Delphes package.

    hep-phPRD(2016)·17 citations
11. 11*

    Probing dark particles indirectly at the CEPC

    Qing-Hong Cao🇨🇳 · Yang Li🇨🇳 · Bin Yan🇨🇳 · Ya Zhang🇨🇳 · Zhen Zhang🇨🇳

    When dark matter candidate and its parent particles are nearly degenerate, it would be difficult to probe them at the Large Hadron Collider directly. We propose to explore their quantum loop effects at the CEPC through the golden channel process $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$. We use a renormalizable toy model consisting of a new scalar and a fermion to describe new physics beyond the Standard Model. The new scalar and fermion are general multiplets of the $SU(2{)}_L\times U(1{)}_Y$ symmetry, and couple to the muon lepton through Yukawa interaction. We calculate their loop contributions to anomalous $\gamma {\mu }^{+}{\mu }^{-}$ and $Z{\mu }^{+}{\mu }^{-}$ couplings which can be applied to many new physics models. The prospects of their effects at the CEPC are also examined assuming a 0.002 accuracy in the cross section measurement.

    hep-phNPB(2016)·12 citations
12. 12*

    Role of magnetic interactions in neutron stars

    Souvik Priyam Adhya🇮🇳 · Pradip K. Roy🇮🇳

    In this work, we present a calculation of the non-Fermi liquid correction to the specific heat of magnetized degenerate quark matter present at the core of the neutron star. The role of non-Fermi liquid corrections to the neutrino emissivity has been calculated beyond leading order. We extend our result to the evaluation of the pulsar kick velocity and cooling of the star due to such anomalous corrections and present a comparison with the simple Fermi liquid case.

    hep-phEPJ Web Conf.(2015)·1 citation
13. 13*

    NNVub: a Neural Network Approach to $B\to X_u\ell \nu$

    Paolo Gambino🇮🇹 · Kristopher J. Healey🇮🇹 · Cristina Mondino🇮🇹

    We use artificial neural networks to parameterize the shape functions in inclusive semileptonic $B$ decays without charm. Our approach avoids the adoption of functional form models and allows for a straightforward implementation of all experimental and theoretical constraints on the shape functions. The results are used to extract $|V_{ub}|$ in the GGOU framework and compared with the original GGOU paper and the latest HFAG results, finding good agreement in both cases. The possible impact of future Belle-II data on the $M_X$ distribution is also discussed.

    hep-phhep-exPRD(2016)·32 citations
14. 14*

    Some heavy vector and tensor meson decay constants in light-front quark model

    Chao-Qiang Geng🇨🇳 · Chong-Chung Lih🇹🇼 · Chuanhui Xia🇨🇳

    We study the decay constants ($f_M$) of the heavy vector ($D^{\ast }$, $D_s^{\ast }$, $B^{\ast }$, $B_s^{\ast }$, $B_c^{\ast }$) and tensor ($D_2^{\ast }$, $D_{s2}^{\ast }$, $B_2^{\ast }$, $B_{s2}^{\ast }$) mesons in the light front quark model. With the known pseudoscalar meson decay constants of $f_D$, $f_{D_s}$, $f_B$, $f_{B_s}$, and $f_{B_c}$ as the input parameters to determine the light-front meson wave functions, we obtain that $f_{D^{\ast },D_s^{\ast },B^{\ast },B_s^{\ast },B_c^{\ast }}=(252.0_{-11.6}^{+13.8}$, $318.3_{-12.6}^{+15.3}$ , $201.9_{-41.4}^{+43.2}$, $244.2\pm 7.0$, $473.4\pm 18.2$) and $(264.9_{-9.5}^{+10.2}$, $330.9_{-9.0}^{+9.9}$, $220.2_{-46.2}^{+49.1}$, $265.7\pm 8.0$, $487.6\pm 19.2$) MeV with Gaussian and power-law wave functions, respectively, while $f_{D_2^{\ast },D_{s2}^{\ast },B_2^{\ast },B_{s2}^{\ast }}$= ($143.6_{-21.8}^{+24.9}$, $209.5_{-24.2}^{+29.1}$, $80.9_{-27.7}^{+33.8}$, $109.7_{-15.0}^{+15.7}$) MeV with only Gaussian wave functions.

    hep-phEPJC(2016)·21 citations
15. 15*

    Way-out to the Gravitino problem in intersecting D-brane Pati-Salam models

    Andrea Addazi🇮🇹 · Maxim Khlopov🇫🇷

    We discuss the gravitino problem in contest of the Exotic see-saw mechanism for neutrinos and Leptogenesis, UV completed by intersecting D-branes Pati-Salam models. In the Exotic see-saw model, supersymmetry is broken at high scales $M_{SUSY}>10^9\mathrm{GeV}$ and this seems in contradiction with gravitino bounds from inflation and baryogenesis. However, if gravitino is the Lightest Stable Supersymmetric Particle, it will not decay into other SUSY particles, avoiding the gravitino problem and providing a good Cold Dark Matter. Gravitini are Super Heavy Dark Particles and they can be produced by non-adiabatic expansion during inflation. Intriguingly, from bounds on the correct abundance of dark matter, we also constrain the neutrino sector. We set a limit on the exotic instantonic coupling of $<10^{-2}÷10^{-3}$. This also sets important constrains on the Calabi-Yau compactifications and on the string scale. This model strongly motivates very high energy DM indirect detection of neutrini and photons of $10^{11}÷10^{13}\mathrm{GeV}$: gravitini can decay on them in a cosmological time because of soft R-parity breaking effective operators.

    hep-phgr-qchep-thMod.Phys.Lett.A(2016)·16 citations
16. 16*

    Relativistic corrections to the pair $B_c$-meson production in $e^{+}{e}^{-}$ annihilation

    A.A. Karyasov🇷🇺 · A.P. Martynenko🇷🇺 · F.A. Martynenko (Samara University)🇷🇺

    Relativistic corrections to the pair $B_c$-meson production in $e^{+}{e}^{-}$-annihilation are calculated. We investigate a production of pair pseudoscalar, vector and pseudoscalar+vector $B_c$-mesons in the leading order perturbative quantum chromodynamics and relativistic quark model. Relativistic expressions of the pair production cross sections are obtained. Their numerical evaluation shows that relativistic effects in the production amplitudes and bound state wave functions three times reduce nonrelativistic results at the center-of-mass energy s=22 GeV.

    hep-phNPB(2016)·18 citations
17. 17*

    $A_4\times U(1{)}_{PQ}$ Model for the Lepton Flavor Structure and the Strong $CP$ Problem

    Takaaki Nomura🇰🇷 · Yusuke Shimizu🇯🇵 · Toshifumi Yamada🇰🇷

    We present a model with $A_4\times U(1{)}_{PQ}$ lepton flavor symmetry which explains the origin of the lepton flavor structure and also solves the strong $CP$ problem. Standard model gauge singlet fields, so-called "flavons", charged under the $A_4\times U(1{)}_{PQ}$ symmetry are introduced and are coupled with the lepton and the Higgs sectors. The flavon vacuum expectation values (VEVs) trigger spontaneous breaking of the $A_4\times U(1{)}_{PQ}$ symmetry. The breaking pattern of the $A_4$ accounts for the tri-bimaximal neutrino mixing and the deviation from it due to the non-zero ${\theta }_{13}$ angle, and the breaking of the $U(1{)}_{PQ}$ gives rise to a pseudo-Nambu-Goldstone boson, axion, whose VEV cancels the QCD $\theta$ term. We investigate the breaking of the $A_4\times U(1{)}_{PQ}$ symmetry through an analysis on the scalar potential and further discuss the properties of the axion in the model, including its decay constant, mass and coupling with photons. It is shown that the axion decay constant is related with the right-handed neutrino mass through the flavon VEVs. Experimental constraints on the axion and their implications are also studied.

    hep-phJHEP(2016)·11 citations
18. 18*

    Critical Scaling and a Dynamical Higgs Boson

    Philip D. Mannheim🇺🇸

    In a quantum electrodynamics theory that is realized by critical scaling and anomalous dimensions, the action is not chiral invariant and there are no dynamical Goldstone or Higgs boson bound states. In the mean-field approximation to a chiral invariant four-fermion theory the associated mean-field sector action is not chiral invariant either and it also possesses no dynamical bound states, with Goldstone and Higgs bosons instead being generated by an accompanying four-fermion residual interaction. In this paper we show that if a critical scaling electrodynamics in which the dimension $d_{\theta }$ of $\bar{\psi }\psi$ is reduced from three to two is augmented with a four-fermion interaction, precisely because it possesses no dynamical bound states the electrodynamic sector can be reinterpreted as a mean-field approximation to a larger theory that is chiral symmetric. And with $d_{\theta }=2$ we show in this larger theory there is a residual interaction that then does generate dynamical Goldstone and Higgs bosons in scattering amplitudes that are completely finite. While the dynamically generated Goldstone boson is massless, the dynamically induced Higgs boson is found to be a narrow resonance just above threshold, with its width being a diagnostic that could potentially enable one to distinguish between a dynamical Higgs boson and an elementary one.

    hep-phhep-thJ.Phys.Conf.Ser.(2019)·2 citations
19. 19*

    Angular analysis of B -> J/psi K1 : towards a model independent determination of the photon polarization with B-> K1 gamma

    E. Kou🇫🇷 · A. Le Yaouanc🇫🇷 · A. Tayduganov🇫🇷

    We propose a model independent extraction of the hadronic information needed to determine the photon polarization of the b-> s gamma process by the method utilizing the B -> K1 gamma -> K pi pi gamma angular distribution. We show that exactly the same hadronic information can be obtained by using the B -> J/psi K1 -> J/psi K pi pi channel, which leads to a much higher precision.

    hep-phhep-exPLB(2016)·11 citations
20. 20*

    Invisible Axion-Like Dark Matter from Electroweak Bosonic Seesaw

    Hiroyuki Ishida🇯🇵 · Shinya Matsuzaki🇯🇵 · Yuya Yamaguchi🇯🇵

    We explore a model based on the classically-scale invariant standard model (SM) with a strongly coupled vector-like dynamics, which is called hypercolor (HC). The scale symmetry is dynamically broken by the vector-like condensation at the TeV scale, so that the SM Higgs acquires the negative mass-squared by the bosonic seesaw mechanism to realize the electroweak symmetry breaking. An elementary pseudoscalar $S$ is introduced to give masses for the composite Nambu-Goldstone bosons (HC pions): the HC pion can be a good target to explore through a diphoton channel at the LHC. As the consequence of the bosonic seesaw, the fluctuating mode of $S$, which we call $s$, develops tiny couplings to the SM particles and is predicted to be very light. The $s$ predominantly decays to diphoton and can behave as an invisible axion-like dark matter. The mass of the $s$-dark matter is constrained by currently available cosmological and astrophysical limits to be $10^{-4}\mathrm{eV}\lesssim m_s\lesssim 1\mathrm{eV}$. We find that the sufficient amount of relic abundance for the $s$-dark matter can be accumulated via the coherent oscillation. The detection potential in microwave cavity experiments is also addressed.

    hep-phastro-ph.HEhep-exPRD(2016)·16 citations
21. 21*

    $X(3872)$ production and absorption in a hot hadron gas

    L. M. Abreu🇧🇷 · K. P. Khemchandani🇧🇷 · A. Martinez Torres🇧🇷 · F. S. Navarra🇧🇷 · M. Nielsen🇧🇷

    We calculate the time evolution of the $X(3872)$ abundance in the hot hadron gas produced in the late stage of heavy ion collisions. We use effective field Lagrangians to obtain the production and dissociation cross sections of $X(3872)$. In this evaluation we include diagrams involving the anomalous couplings $\pi D^{\ast }{\bar{D}}^{\ast }$ and $X{\bar{D}}^{\ast }{D}^{\ast }$ and also the couplings of the $X(3872)$ with charged $D$ and $D^{\ast }$ mesons. With these new terms the $X(3872)$ interaction cross sections are much larger than those found in previous works. Using these cross sections as input in rate equations, we conclude that during the expansion and cooling of the hadronic gas, the number of $X(3872)$, originally produced at the end of the mixed QGP/hadron gas phase, is reduced by a factor of 4.

    hep-phPLB(2016)·61 citations
22. 22*

    Baryogenesis from leptomesons

    Dmitry Zhuridov🇵🇱

    Various new physics models, e.g., theories of compositeness, can accommodate the color singlet excited leptons that interact with the leptons, quarks, leptoquarks, etc. A particular type of excited lepton, which at low energies interacts with the Standard Model fermions mainly through the four-fermion coupling to lepton and quark-antiquark (or lepton-antilepton) pair, we call leptomeson. These new particles may contribute to variety of the experimental anomalies such as the discrepancy in the muon g-2. We propose that the leptomesons can generate also the baryon asymmetry that explains the imbalance in ordinary matter and antimatter in the observable universe. We consider the two types of scenarios for this baryogenesis via leptogenesis to occur from either leptomeson oscillations or decays. Both possibilities do not contradict to the small masses of the observable neutrinos and the proton stability. Moreover they can be relevant for the near future collider experiments and do not suffer from the gravitino problem.

    hep-phPRD(2016)·14 citations
23. 23*

    Relativistic two-body calculation of $b\bar{b}$-mesons radiative decays

    A. Barducci🇮🇹 · R. Giachetti🇮🇹 · E. Sorace🇮🇹

    This paper is a prosecution of a previous work where we presented a unified two-fermion covariant scheme which produced very precise results for the masses of light and heavy mesons. We extend the analysis to some radiative decays of mesons ${\rm Y},{\chi }_{b2},h_b,{\chi }_{b1},{\chi }_{b0},{\eta }_b$ and we calculate their branching ratios and their widths. For most of them we can make a comparison with experimental data finding a good agreement.For the decays for which data are not available we compare ours with other recent theoretical previsions.

    hep-phPRD(2017)·6 citations
24. 24*

    On the gravitational seesaw in higher-derivative gravity

    Antonio Accioly🇧🇷 · Breno L. Giacchini🇧🇷 · Ilya L. Shapiro🇧🇷

    Local gravitational theories with more than four derivatives are superrenormalizable, and also may be unitary in the Lee-Wick sense. Thus, it is relevant to study the low-energy properties of these theories, especially to identify observables which might be useful for experimental detection of higher derivatives. Using an analogy with the neutrino Physics, we explore the possibility of a gravitational seesaw mechanism, in which several dimensional parameters of the same order of magnitude produce a hierarchy in the masses of propagating particles. Such a mechanism could make a relatively light degree of freedom detectable in low-energy laboratory and astrophysical observations, such as torsion balance experiments and the bending of light. We demonstrate that such a seesaw mechanism in the six- and more-derivative theories is unable to reduce the lightest mass more than in the simplest four-derivative model. Adding more derivatives to the four-derivative action of gravity makes heavier masses even greater, while the lightest massive ghost is not strongly affected. This fact is favorable for protecting the theory from instabilities, but makes the experimental detection of higher derivatives more difficult.

    ↳ gr-qchep-phhep-thEPJC(2017)·49 citations
25. 25*

    Fermions in five-dimensional brane world models

    Mikhail N. Smolyakov🇷🇺

    In the present paper the fermion fields, living in the background of five-dimensional warped brane world models with compact extra dimension, are thoroughly examined. The Kaluza-Klein decomposition and isolation of the physical degrees of freedom is performed for those five-dimensional fermion field Lagrangians, which admit such a decomposition to be performed in a mathematically consistent way and provide a physically reasonable four-dimensional effective theory. It is also shown that for the majority of five-dimensional fermion field Lagrangians there are no (at least rather obvious) ways to perform the Kaluza-Klein decomposition consistently. Moreover, in these cases one may expect the appearance of various pathologies in the four-dimensional effective theory. Among the cases, for which the Kaluza-Klein decomposition can be performed in a mathematically consistent way, the case, which reproduces the Standard Model by the zero Kaluza-Klein modes most closely regardless of the size of the extra dimension, is examined in detail in the background of the Randall-Sundrum model.

    ↳ hep-thhep-phJHEP(2016)·1 citation
26. 26*

    Distribution amplitudes of radially-excited pi- and K-mesons

    Bo-Lin Li🇨🇳 · Lei Chang🇨🇳 · Fei Gao🇨🇳 · Craig D. Roberts🇺🇸 · Sebastian M. Schmidt🇩🇪 · Hong-Shi Zong🇨🇳

    A symmetry-preserving truncation of the two-body bound-state problem in relativistic quantum field theory is used to compute the leading-twist parton distribution amplitudes (PDAs) for the first radial excitations of the $\pi$- and $K$-mesons. In common with ground states in these channels, the PDAs are found to be dilated with respect to the relevant conformal-limit form and skewed toward the heavier valence-quark in asymmetric systems. In addition, the PDAs of radially-excited pseudoscalar mesons are not positive definite, owing to the fact that dynamical chiral symmetry breaking (DCSB) forces the leptonic decay constant of such states to vanish in the chiral limit. These results highlight that DCSB is expressed visibly in every pseudoscalar meson constituted from light-quarks. Hence, so long as its impact is empirically evident in the pseudoscalar members of a given spectrum level, it is unlikely that chiral symmetry is restored in any of the hadrons that populate this level.

    ↳ nucl-thhep-lathep-phnucl-exPRD(2016)·45 citations
27. 27*

    Higher order anisotropies in the Buda-Lund model: Disentangling flow and density field anisotropies

    Sándor Lökös🇭🇺 · Máté Csanád🇭🇺 · Tamás Csörgő🇭🇺 · Boris Tomášik🇸🇰

    The Buda-Lund hydro model describes an expanding ellipsoidal fireball, and fits the observed elliptic flow and oscillating HBT radii successfully. Due to fluctuations in energy depositions, the fireball shape however fluctuates on an event-by-event basis. The transverse plane asymmetry can be translated into a series of multipole anisotropy coefficients. These anisotropies then result in measurable momentum-space anisotropies, to be measured with respect to their respective symmetry planes. In this paper we detail an extension of the Buda-Lund model to multipole anisotropies and investigate the resulting flow coefficients and oscillations of HBT radii.

    ↳ nucl-thhep-phEPJA(2016)·8 citations
28. 28*

    The Operator Product Expansion Beyond Leading Order for Two-Component Fermions

    Samuel B. Emmons🇺🇸 · Daekyoung Kang🇺🇸 · Lucas Platter🇺🇸

    We consider a homogeneous, balanced gas of strongly interacting fermions in two spin states interacting through a large scattering length. Finite range corrections are needed for a quantitative description of data which experiments and numerical simulations have provided. We use a perturbative field theoretical framework and a tool called the Operator Product Expansion (OPE), which together allow for the expression of finite range corrections to the universal relations and momentum distribution. Using the OPE, we derive the $1/k^6$ part of the momentum tail, which is related to the sum of the derivative of the energy with respect to the finite range and the averaged kinetic energy of opposite spin pairs. By comparing the $1/k^4$ term and the $1/k^6$ correction in the momentum distribution to provided Quantum Monte Carlo (QMC) data, we show that including the $1/k^6$ part offers marked improvements. Our field theoretical approach allows for a clear understanding of the role of the scattering length and finite effective range in the universal relations and the momentum distribution.

    ↳ cond-mat.quant-gashep-phnucl-thPRA(2016)·8 citations
29. 29*

    Measurement of the Higgs boson mass and $e^{+}{e}^{-}\to ZH$ cross section using $Z\to {\mu }^{+}{\mu }^{-}$ and $Z\to e^{+}{e}^{-}$ at the ILC

    Jacqueline Yan🇯🇵 · Shun Watanuki🇯🇵 · Keisuke Fujii🇯🇵 · Akimasa Ishikawa🇯🇵 · Daniel Jeans🇯🇵 · Jan Strube🇺🇸 · Junping Tian🇯🇵 · Hitoshi Yamamoto🇯🇵

    This paper presents a full simulation study of the measurement of the production cross section (${\sigma }_{\mathrm{ZH}}$) of the Higgsstrahlung process ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to \mathrm{ZH}$ and the Higgs boson mass ($M_{\mathrm{H}}$) at the International Linear Collider (ILC), using events in which a Higgs boson recoils against a Z boson decaying into a pair of muons or electrons. The analysis is carried out for three center-of-mass energies $\sqrt{s}$ = 250, 350, and 500 GeV, and two beam polarizations ${\mathrm{e}}_{\mathrm{L}}^{-}{\mathrm{e}}_{\mathrm{R}}^{+}$ and ${\mathrm{e}}_{\mathrm{R}}^{-}{\mathrm{e}}_{\mathrm{L}}^{+}$, for which the polarizations of ${\mathrm{e}}^{-}$ and ${\mathrm{e}}^{+}$ are $\left(P{\mathrm{e}}^{-},P{\mathrm{e}}^{+}\right)$ =($-$80\%, +30\%) and (+80\%, $-$30\%), respectively. Assuming an integrated luminosity of 250 $\mathrm{f}{\mathrm{b}}^{-1}$ for each beam polarization at $\sqrt{s}$ = 250 GeV, where the best lepton momentum resolution is obtainable, ${\sigma }_{\mathrm{ZH}}$ and $M_{\mathrm{H}}$ can be determined with a precision of 2.5\% and 37 MeV for ${\mathrm{e}}_{\mathrm{L}}^{-}{\mathrm{e}}_{\mathrm{R}}^{+}$ and 2.9\% and 41 MeV for ${\mathrm{e}}_{\mathrm{R}}^{-}{\mathrm{e}}_{\mathrm{L}}^{+}$, respectively. Regarding a 20 year ILC physics program, the expected precisions for the $\mathrm{HZZ}$ coupling and $M_{\mathrm{H}}$ are estimated to be 0.4\% and 14 MeV, respectively. The event selection is designed to optimize the precisions of ${\sigma }_{\mathrm{ZH}}$ and $M_{\mathrm{H}}$ while minimizing the bias on the measured ${\sigma }_{\mathrm{ZH}}$ due to discrepancy in signal efficiencies among Higgs decay modes. For the first time, model independence has been demonstrated to a sub-percent level for the ${\sigma }_{\mathrm{ZH}}$ measurement at each of the three center-of-mass energies. The results presented show the impact of center-of-mass energy and beam polarization on the evaluated precisons and serve as a benchmark for the planning of the ILC run scenario.

    ↳ hep-exhep-phPRD(2016)·83 citations
30. 30*

    Lattice constraints on the thermal photon rate

    J. Ghiglieri🇨🇭 · O. Kaczmarek🇩🇪 · M. Laine🇨🇭 · F. Meyer🇩🇪

    We estimate the photon production rate from an SU(3) plasma at temperatures of about 1.1Tc and 1.3Tc. Lattice results for the vector current correlator at spatial momenta k ~ (2-6)T are extrapolated to the continuum limit and analyzed with the help of a polynomial interpolation for the corresponding spectral function, which vanishes at zero frequency and matches to high-precision perturbative results at large invariant masses. For small invariant masses the interpolation is compared with the NLO weak-coupling result, hydrodynamics, and a holographic model. At vanishing invariant mass we extract the photon rate which for k \gsim 3T is found to be close to the NLO weak-coupling prediction. For k \lsim 2T uncertainties remain large but the photon rate is likely to fall below the NLO prediction, in accordance with the onset of a strongly interacting behaviour characteristic of the hydrodynamic regime.

    ↳ hep-lathep-phPRD(2016)·75 citations
31. 31*

    Bounce inflation in $f(T)$ Cosmology: A unified inflaton-quintessence field

    Kazuharu Bamba🇯🇵 · G.G.L. Nashed🇪🇬 · W. El Hanafy🇪🇬 · Sh.K. Ibraheem🇪🇬

    We investigate a bounce inflation model with a graceful exit into the Friedmann-Robertson-Walker (FRW) decelerated Universe within $f(T)$ gravity framework, where $T$ is the torsion scalar in the teleparallelism. We study the cosmic thermal evolution, the model predicts a supercold Universe during the precontraction phase, which is consistent with the requirements of the slow-roll models, while it performs a reheating period by the end of the contraction with a maximum temperature just below the grand unified theory (GUT) temperature. However, it matches the radiation temperature of the hot big bang at later stages. The equation-of-state due to the effective gravitational sector suggests that our Universe is self-accelerated by teleparallel gravity. We assume the matter component to be a canonical scalar field. We obtain the scalar field potential that is induced by the $f(T)$ theory. The power spectrum of the model is nearly scale invariant. In addition, we show that the model unifies inflaton and quintessence fields in a single model. Also, we revisited the primordial fluctuations in $f(T)$ bounce cosmology, to study the fluctuations that are produced at the precontraction phase.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2016)·109 citations
32. 32*

    Low-energy hadronic cross sections measurements at BaBar, and implication for the g-2 of the muon

    Denis Bernard · The BaBar Collaboration

    The BaBar Collaboration has an intensive program studying the cross sections of hadron production in low-energy e+e- annihilation, accessible via initial-state radiation. Our measurements allow a significant improvement in the precision of the predicted value of the muon anomalous magnetic moment. These improvements are necessary for shedding light on the current > 3 sigma difference between the predicted and the experimental values. We have published results on a number of processes with two to six hadrons in the final state, and other final states are currently under investigation. We report here on the most recent results obtained by analysing the entire Babar dataset.

    ↳ hep-exhep-phPoS(2016)·1 citation
33. 33*

    Algebraic model for single-particle energies of $\Lambda$ hypernuclei

    L. Fortunato🇮🇹 · K. Hagino🇯🇵

    A model is proposed for the spectrum of $\Lambda$ hypernuclei based on the $u(3)\times u(2)$ Lie algebra, in which the internal degrees of freedom of the spin-1/2 $\Lambda$ particle are treated in the Fermionic $u(2)$ scheme, while the motion of the hyperon inside a nucleus is described in the Bosonic $u(3)$ harmonic oscillator scheme. Within this model, a simple formula for single-particle energies of the $\Lambda$ particle is obtained from the natural dynamical symmetry. The formula is applied to the experimental data on the reaction spectroscopy for the ${}_{\Lambda }^{89}$Y and ${}_{\Lambda }^{51}$V hypernuclei, providing a clear theoretical interpretation of the observed structures.

    ↳ nucl-thhep-ph1 citation
34. 34*

    Gauge cooling for the singular-drift problem in the complex Langevin method --a test in Random Matrix Theory for finite density QCD

    Keitaro Nagata🇯🇵 · Jun Nishimura🇯🇵 · Shinji Shimasaki🇯🇵

    Recently, the complex Langevin method has been applied successfully to finite density QCD either in the deconfinement phase or in the heavy dense limit with the aid of a new technique called the gauge cooling. In the confinement phase with light quarks, however, convergence to wrong limits occurs due to the singularity in the drift term caused by small eigenvalues of the Dirac operator including the mass term. We propose that this singular-drift problem should also be overcome by the gauge cooling with different criteria for choosing the complexified gauge transformation. The idea is tested in chiral Random Matrix Theory for finite density QCD, where exact results are reproduced at zero temperature with light quarks. It is shown that the gauge cooling indeed changes drastically the eigenvalue distribution of the Dirac operator measured during the Langevin process. Despite its non-holomorphic nature, this eigenvalue distribution has a universal diverging behavior at the origin in the chiral limit due to a generalized Banks-Casher relation as we confirm explicitly.

    ↳ hep-lathep-phhep-thJHEP(2016)·49 citations
35. 35*

    Fluid/gravity correspondence: Second order transport coefficients in compactified D4-branes

    Chao Wu🇨🇳 · Yidian Chen🇨🇳 · Mei Huang🇨🇳

    We develop the boundary derivative expansion (BDE) formalism of fluid/gravity correspondence to nonconformal version through the compactified, near-extremal black D4-brane. We offer an explicit calculation of 9 second order transport coefficients, i.e., the ${\tau }_{\pi },{\tau }_{\pi }^{\ast },{\tau }_{\Pi },{\lambda }_{1,2,3}$ and ${\xi }_{1,2,3}$ for the strongly coupled, uncharged and nonconformal relativistic fluid which is the holographic dual of compactified, near extremal black D4-brane. We also show that the nonconformal fluid considered in this work is free of causal problem and admits the Haack-Yarom relation $4{\lambda }_1+{\lambda }_2=2\eta {\tau }_{\pi }$.

    ↳ hep-thhep-phJHEP(2017)·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.