Tue·Mar 15, 2016Tuesday·March 15, 2016

1. 01*

   Frame-Covariant Formulation of Inflation in Scalar-Curvature Theories

   Daniel Burns🇬🇧 · Sotirios Karamitsos🇬🇧 · Apostolos Pilaftsis🇬🇧

   We develop a frame-covariant formulation of inflation in the slow-roll approximation by generalizing the inflationary attractor solution for scalar-curvature theories. Our formulation gives rise to new generalized forms for the potential slow-roll parameters, which enable us to examine the effect of conformal transformations and inflaton reparameterizations in scalar-curvature theories. We find that cosmological observables, such as the power spectrum, the spectral indices and their runnings, can be expressed in a concise manner in terms of the generalized potential slow-roll parameters which depend on the scalar-curvature coupling function, the inflaton wavefunction, and the inflaton potential. We show how the cosmological observables of inflation are frame-invariant in this generalized potential slow-roll formalism, as long as the end-of-inflation condition is appropriately extended to become frame-invariant as well. We then apply our formalism to specific scenarios, such as the induced gravity inflation, Higgs inflation and $F(R)$ models of inflation, and obtain more accurate results, without making additional approximations to the potential. Our results are shown to be consistent to lowest order with those presented in the literature. Finally, we outline how our frame-covariant formalism can be naturally extended beyond the tree-level approximation, within the framework of the Vilkovisky--DeWitt effective action.

   hep-phgr-qchep-thNPB(2016)·66 citations
2. 02*

   Physics Reach of DUNE with a Light Sterile Neutrino

   Sanjib Kumar Agarwalla🇮🇳 · Sabya Sachi Chatterjee🇮🇳 · Antonio Palazzo🇮🇹

   We investigate the implications of one light eV scale sterile neutrino on the physics potential of the proposed long-baseline experiment DUNE. If the future short-baseline experiments confirm the existence of sterile neutrinos, then it can affect the mass hierarchy (MH) and CP-violation (CPV) searches at DUNE. The MH sensitivity still remains above 5$\sigma$ if the three new mixing angles (${\theta }_{14},{\theta }_{24},{\theta }_{34}$) are all close to ${\theta }_{13}$. In contrast, it can decrease to 4$\sigma$ if the least constrained mixing angle ${\theta }_{34}$ is close to its upper limit $\sim 30^0$. We also assess the sensitivity to the CPV induced both by the standard CP-phase ${\delta }_{13}\equiv \delta$, and the new CP-phases ${\delta }_{14}$ and ${\delta }_{34}$. In the 3+1 scheme, the discovery potential of CPV induced by ${\delta }_{13}$ gets deteriorated compared to the 3$\nu$ case. In particular, the maximal sensitivity (reached around ${\delta }_{13}$ $\sim$ $\pm$ $90^0$) decreases from $5\sigma$ to $4\sigma$ if all the three new mixing angles are close to ${\theta }_{13}$. It can further diminish to almost $3\sigma$ if ${\theta }_{34}$ is large ($\sim 30^0$). The sensitivity to the CPV due to ${\delta }_{14}$ can reach 3$\sigma$ for an appreciable fraction of its true values. Interestingly, ${\theta }_{34}$ and its associated phase ${\delta }_{34}$ can influence both the ${\nu }_e$ appearance and ${\nu }_{\mu }$ disappearance channels via matter effects, which in DUNE are pronounced. Hence, DUNE can also probe CPV induced by ${\delta }_{34}$ provided ${\theta }_{34}$ is large. We also reconstruct the two phases ${\delta }_{13}$ and ${\delta }_{14}$. The typical 1$\sigma$ uncertainty on ${\delta }_{13}$ (${\delta }_{14}$) is $\sim 20^0$ ($30^0$) if ${\theta }_{34}=0$. The reconstruction of ${\delta }_{14}$ (but not that of ${\delta }_{13}$) degrades if ${\theta }_{34}$ is large.

   hep-phhep-exphysics.ins-detJHEP(2016)·71 citations
3. 03*

   Tadpole-Induced Electroweak Symmetry Breaking and pNGB Higgs Models

   Roni Harnik🇺🇸 · Kiel Howe🇺🇸 · John Kearney🇺🇸

   We investigate induced electroweak symmetry breaking (EWSB) in models in which the Higgs is a pseudo-Nambu-Goldstone boson (pNGB). In pNGB Higgs models, Higgs properties and precision electroweak measurements imply a hierarchy between the EWSB and global symmetry-breaking scales, $v_H\ll f_H$. When the pNGB potential is generated radiatively, this hierarchy requires fine-tuning to a degree of at least $\sim v_H^2/f_H^2$. We show that if Higgs EWSB is induced by a tadpole arising from an auxiliary sector at scale $f_{\Sigma }\ll v_H$, this tuning is significantly ameliorated or can even be removed. We present explicit examples both in Twin Higgs models and in Composite Higgs models based on $SO(5)/SO(4)$. For the Twin case, the result is a fully natural model with $f_H\sim 1$ TeV and the lightest colored top partners at 2 TeV. These models also have an appealing mechanism to generate the scales of the auxiliary sector and Higgs EWSB directly from the scale $f_H$, with a natural hierarchy $f_{\Sigma }\ll v_H\ll f_H\sim \mathrm{TeV}$. The framework predicts modified Higgs coupling as well as new Higgs and vector states at LHC13.

   hep-phJHEP(2017)·41 citations
4. 04*

   Is there really a $W\to \tau \nu$ puzzle?

   Bhubanjyoti Bhattacharya🇨🇦 · Alakabha Datta🇺🇸 · David London🇨🇦

   According to the Particle Data Group, the measurements of $\mathcal{B}(W^{+}\to {\tau }^{+}{\nu }_{\tau })$ and $\mathcal{B}(W^{+}\to {\ell }^{+}{\nu }_{\ell })$ ($\ell =e,\mu$) disagree with one another at the $2.3\sigma$ level. In this paper, we search for a new-physics (NP) explanation of this $W\to \tau \nu$ puzzle. We consider two NP scenarios: (i) the $W$ mixes with a $W^{\prime }$ boson that couples preferentially to the third generation, (ii) ${\tau }_{L,R}$ and ${\nu }_{\tau L}$ mix with isospin-triplet leptons. Unfortunately, once other experimental constraints are taken into account, neither scenario can explain the above experimental result. Our conclusion is that the $W\to \tau \nu$ puzzle is almost certainly just a statistical fluctuation.

   hep-phhep-exPRD(2016)·1 citation
5. 05*

   Lectures on Dark Matter Physics

   Mariangela Lisanti🇺🇸

   Rotation curve measurements provided the first strong indication that a significant fraction of matter in the Universe is non-baryonic. Since then, a tremendous amount of progress has been made on both the theoretical and experimental fronts in the search for this missing matter, which we now know constitutes nearly 85% of the Universe's matter density. These series of lectures, first given at the TASI 2015 summer school, provide an introduction to the basics of dark matter physics. They are geared for the advanced undergraduate or graduate student interested in pursuing research in high-energy physics. The primary goal is to build an understanding of how observations constrain the assumptions that can be made about the astro- and particle physics properties of dark matter. The lectures begin by delineating the basic assumptions that can be inferred about dark matter from rotation curves. A detailed discussion of thermal dark matter follows, motivating Weakly Interacting Massive Particles, as well as lighter-mass alternatives. As an application of these concepts, the phenomenology of direct and indirect detection experiments is discussed in detail.

   hep-phastro-ph.CO171 citations
6. 06*

   Distinctive ultraviolet structure of extra-dimensional Yang-Mills theories by integration of heavy Kaluza-Klein modes

   I. García-Jiménez🇲🇽 · H. Novales-Sánchez🇲🇽 · J. J. Toscano🇲🇽

   One-loop Standard Model observables produced by virtual heavy Kaluza-Klein fields play a prominent role in the minimal model of universal extra dimensions. Motivated by this aspect, we integrate out all the Kaluza-Klein heavy modes coming from the Yang-Mills theory set on a spacetime with an arbitrary number, $n$, of compact extra dimensions. After fixing the gauge with respect to the Kaluza-Klein heavy gauge modes in a covariant manner, we calculate a gauge independent effective Lagrangian expansion containing multiple Kaluza-Klein sums that entail a bad divergent behavior. We use the Epstein-zeta function to regularize and characterize discrete divergences within such multiple sums, and then we discuss the interplay between the number of extra dimensions and the degree of accuracy of effective Lagrangians to generate or not divergent terms of discrete origin. We find that nonrenormalizable terms with mass dimension $k$ are finite as long as $k>4+n$. Multiple Kaluza-Klein sums of nondecoupling logarithmic terms, not treatable by Epstein-zeta regularization, are produced by four-dimensional momentum integration. On the grounds of standard renormalization, we argue that such effects are unobservable.

   hep-phPRD(2016)·6 citations
7. 07*

   Thermo-magnetic effects in quark matter: Nambu--Jona-Lasinio model constrained by lattice QCD

   R. L. S. Farias🇧🇷 · V. S. Timoteo🇧🇷 · S. S. Avancini🇧🇷 · M. B. Pinto🇧🇷 · G. Krein🇧🇷

   The phenomenon of inverse magnetic catalysis of chiral symmetry in QCD predicted by lattice simulations can be reproduced within the Nambu--Jona-Lasinio model if the coupling~$G$ of the model decreases with the strength $B$ of the magnetic field and temperature~$T$. The thermo-magnetic dependence of $G(B,T)$ is obtained by fitting recent lattice QCD predictions for the chiral transition order parameter. Different thermodynamic quantities of magnetized quark matter evaluated with $G(B,T)$ are compared with the ones obtained at constant coupling, $G$. The model with $G(B,T)$ predicts a more dramatic chiral transition as the field intensity increases. In addition, the pressure and magnetization always increase with $B$ for a given temperature. Being parametrized by four magnetic field dependent coefficients and having a rather simple exponential thermal dependence our accurate ansatz for the coupling constant can be easily implemented to improve typical model applications to magnetized quark matter.

   hep-phhep-latnucl-thEPJA(2017)·146 citations
8. 08*

   Evidence for Some New Hyperon Resonances -- to be Checked by $K_L$ Beam Experiments

   B. S. Zou🇨🇳

   Quenched and unquenched quark models predict very different patterns for the spectrum of the low excited hyperon states. Evidence is accumulating for the existence of some new hyperon resonances, such as a ${\Sigma }^{\ast }$ of spin-parity $J^P=1/2^{-}$ around 1400 MeV instead of 1620 MeV as listed in PDG, a new $\Sigma (1540)3/2^{-}$ resonance, a new narrow $\Lambda (1670)3/2^{-}$ resonance and a new $\Lambda (1680)3/2^{+}$ resonance. All these new hyperon resonances fit in the predicted pattern of the unquenched quark models very well. It is extremely important to check and establish the spectrum of these low excited hyperon states by the proposed $K_L$ beam experiments at JLAB.

   hep-phnucl-th4 citations
9. 09*

   Positronium energy levels at order $m{\alpha }^7$: Product contributions in the two-photon-annihilation channel

   Gregory S. Adkins🇺🇸 · Lam M. Tran🇺🇸 · Ruihan Wang🇺🇸

   Ongoing improvements in the measurement of positronium transition intervals motivate the calculation of the $O(m{\alpha }^7)$ corrections to these intervals. In this work we focus on corrections to the spin-singlet parapositronium energies involving virtual annihilation to two photons in an intermediate state. We have evaluated all contributions to the positronium S-state energy levels that can be written as the product of a one-loop correction on one side of the annihilation event and another one-loop correction on the other side. These effects contribute $\Delta E=-0.561971(25)m{\alpha }^7/{\pi }^3$ to the parapositronium ground state energy.

   hep-phPRA(2016)·19 citations
10. 10*

    Lepton mass and mixing in a Neutrino Mass Model based on $S_4$ flavor symmetry

    V. V. Vien🇻🇳

    We study a neutrino mass model based on $S_4$ flavor symmetry which accommodates lepton mass, mixing with non-zero ${\theta }_{13}$ and CP violation phase. The spontaneous symmetry breaking in the model is imposed to obtain the realistic neutrino mass and mixing pattern at the tree- level with renormalizable interactions. Indeed, the neutrinos get small masses from one $SU(2{)}_L$ doubplet and two $SU(2{)}_L$ singlets in which one being in $\underline{2}$ and the two others in $\underline{3}$ under $S_4$ with both the breakings $S_4\to S_3$ and $S_4\to Z_3$ are taken place in charged lepton sector and $S_4\to \mathcal{K}$ in neutrino sector. The model also gives a remarkable prediction of Dirac CP violation ${\delta }_{CP}=\frac{\pi }{2}$ or $-\frac{\pi }{2}$ in the both normal and inverted spectrum which is still missing in the neutrino mixing matrix. The relation between lepton mixing angles is also represented.

    hep-phInt.J.Mod.Phys.A(2016)·17 citations
11. 11*

    On the polarization of fermion in an intermediate state

    A.E. Kaloshin🇷🇺 · V.P. Lomov🇷🇺

    We show that calculation of a final fermion polarization (for a pure initial state) is equivalent to the problem of looking for complete polarization axis of bispinor. This gives the method for calculation of polarization applicable both for final and intermediate state fermions. We suggest to use fermion propagator (bare or dressed) in form of spectral representation, which gives the orthogonal off-shell energy projectors. This representation leads to covariant separation of particle and antiparticle contributions and gives a natural definition for polarization of intermediate state fermion. The most evident application is related with consistent description of $t$-quark polarization.

    hep-phInt.J.Mod.Phys.A(2017)·2 citations
12. 12*

    Parameter Limits for Neutrino Oscillation with Decoherence in KamLAND

    G. Balieiro Gomes🇧🇷 · M. M. Guzzo🇧🇷 · P. C. de Holanda🇧🇷 · R. L. N. Oliveira🇧🇷

    In the framework of quantum open systems we analyze data from KamLAND by using a model that considers neutrino oscillation in a three-family approximation with the inclusion of the decoherence effect. Using a ${\chi }^2$ test we find new limits for the decoherence parameter which we call $\gamma$, considering the most recent data by KamLAND. Assuming an energy dependence of the type $\gamma ={\gamma }_0{\left(E/E_0\right)}^n$, in 95 \% C.L. the limits found are $3.7\times 10^{-24}GeV$ for $n=-1$, $6.8\times 10^{-22}GeV$ for $n=0$, and $1.5\times 10^{-19}GeV$ for $n=1$ on the energy dependence.

    hep-phPRD(2017)·60 citations
13. 13*

    Macroscopic detection of deformed QM by the harmonic oscillator

    Michael Maziashvili🇬🇪

    Based on the nonperturbative analysis, we show that the classical motion of harmonic oscillator derived from the deformed QM is manifestly in contradiction with observations. For this reason, we take an alternate way for estimating the effect and discuss its possible observational manifestations in macrophysics.

    hep-phquant-phAnnals Phys.(2017)·2 citations
14. 14*

    The chaotic effects in a nonlinear QCD evolution equation

    Wei Zhu🇨🇳 · Zhenqi Shen🇨🇳 · Jianhong Ruan🇨🇳

    The corrections of gluon fusion to the DGLAP and BFKL equations are discussed in a united partonic framework. The resulting nonlinear evolution equations are the well-known GLR-MQ-ZRS equation and a new evolution equation. Using the available saturation models as input, we find that the new evolution equation has the chaos solution with positive Lyaponov exponents in the perturbative range. We predict a new kind of shadowing caused by chaos, which blocks the QCD evolution in a critical small $x$ range. The blocking effect in the evolution equation may explain the Abelian gluon assumption and even influence our expectations to the projected Large Hadron Electron Collider (LHeC), Very Large Hadron Collider (VLHC) and the upgrade (CppC) in a circular $e^{+}{e}^{-}$ collider (SppC).

    hep-phNPB(2016)·31 citations
15. 15*

    Quark ACM with topologically generated gluon mass

    Ishita Dutta Choudhury🇮🇳 · Amitabha Lahiri🇮🇳

    We investigate the effect of a small, gauge-invariant mass of the gluon on the anomalous chromomagnetic moment of quarks (ACM) by perturbative calculations at one loop level. The mass of the gluon is taken to have been generated via a topological mass generation mechanism, in which the gluon acquires a mass through its interaction with an antisymmetric tensor field $B_{\mu \nu }$. For a small gluon mass $(<10$ MeV), we calculate the ACM at momentum transfer $q^2=-M_Z^2$. We compare those with the ACM calculated for the gluon mass arising from a Proca mass term. We find that the ACM of up, down, strange and charm quarks vary significantly with the gluon mass, while the ACM of top and bottom quarks show negligible gluon mass dependence. The mechanism of gluon mass generation is most important for the strange quarks ACM, but not so much for the other quarks. We also show the results at $q^2=-m_t^2$. We find that the dependence on gluon mass at $q^2=-m_t^2$ is much less than at $q^2=-M_Z^2$ for all quarks.

    hep-phMod.Phys.Lett.A(2016)·0 citations
16. 16*

    Hadronic molecular states from the $K{\bar{K}}^{\ast }$ interaction

    Pei-Liang Lü🇨🇳 · Jun He🇨🇳

    In this work, the $K{\bar{K}}^{\ast }$ interaction is studied in a quasipotential Bethe-Salpeter equation approach combined with the one-boson-exchange model. With the help of the hidden-gauge Lagrangian, the exchanges of pseudoscalar mesons ($\pi$ and $\eta$) and vector mesons ($\rho$, $\omega$ and $\varphi$) are considered to describe the $K{\bar{K}}^{\ast }$ interaction. Besides the direct vector-meson exchange which can be related to the Weinberg-Tomozawa term, pseudoscalar-meson exchanges also play important roles in the mechanism of the $K{\bar{K}}^{\ast }$ interaction. The poles of scattering amplitude are searched to find the molecular states produced from the $K{\bar{K}}^{\ast }$ interaction. In the case of quantum number $I^G(J^{PC})=0^{+}(1^{++})$, a pole is found with a reasonable cutoff, which can be related to the $f_1(1285)$ in experiment. Another bound state with $0^{-}(1^{+-})$ is also produced from the $K{\bar{K}}^{\ast }$ interaction, which can be related to the $h_1(1380)$. In the isovector sector, the interaction is much weaker and a bound state with $1^{+}(1^{+})$ relevant to the $b_1(1235)$ is produced but at a larger cutoff. Our results suggest that in the hadronic molecular state picture the $f_1(1285)$ and $b_1(1235)$ are the strange partners of the $X(3872)$ and $Z_c(3900)$, respectively.

    hep-phnucl-thEPJA(2016)·20 citations
17. 17*

    About the mass corrections in an abelian Higgs model

    Renata Jora🇷🇴

    We study the corrections to the scalar boson mass in an abelian Higgs model by considering the global properties of the partition function. We find that although the two point function for the Higgs boson receives quantum corrections, the mass of the scalar remains unaltered and thus the physical mass is equal to the bare one.

    hep-phRom.Rep.Phys.(2016)·0 citations
18. 18*

    TeV scale mirage mediation in NMSSM and precision Higgs measurement

    Ken-ichi Okumura🇯🇵

    We propose that the TeV scale mirage mediation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) is a novel solution for the little hierarchy problem in supersymmetry. The 125 GeV Higgs boson can be accommodated with the new quartic coupling or the mixing with the singlet. The fine-tuning measures are estimated numerically and found as low as 10\% or below for $1.5$ TeV gluino and $1$ TeV stop. The higgsino can be as heavy as 500 GeV without deteriorating the fine-tuning. An undesirable singlet-doublet mixing in the Higgs sector is suppressed due to approximate scale symmetries. We investigate the couplings of the Higgs bosons and discuss the prospects for studying them at LHC and ILC.

    hep-phhep-ex1 citation
19. 19*

    Rare Higgs three body decay induced by top-Higgs FCNC coupling in the littlest Higgs Model with T-parity

    Bingfang Yang🇨🇳 · Zhiyong Liu🇨🇳 · Ning Liu🇨🇳

    Motivated by the search for flavor-changing neutral current (FCNC) top quark decays at the LHC, we calculate rare Higgs three body decay $H\to Wbc$ induced by top-Higgs FCNC coupling in the littlest Higgs model with T-parity(LHT). We find that the branching ratios of $H\to Wbc$ in the LHT model can reach $\mathcal{O}(10^{-7})$ in the allowed parameter space.

    hep-phCPC(2017)·3 citations
20. 20*

    Resonant Diphoton Phenomenology Simplified

    Giuliano Panico🇪🇸 · Luca Vecchi🇮🇹 · Andrea Wulzer🇮🇹

    A framework is proposed to describe resonant diphoton phenomenology at hadron colliders in full generality. It can be employed for a comprehensive model-independent interpretation of the experimental data. Within the general framework, few benchmark scenarios are defined as representative of the various phenomenological options and/or of motivated new physics scenarios. Their usage is illustrated by performing a characterization of the 750 GeV excess, based on a recast of available experimental results. We also perform an assessment of which properties of the resonance could be inferred, after discovery, by a careful experimental study of the diphoton distributions. These include the spin J of the new particle and its dominant production mode. Partial information on its CP-parity can also be obtained, but only for $J\ge 2$. The complete determination of the resonance CP properties requires studying the pattern of the initial state radiation that accompanies the resonant diphoton production.

    hep-phhep-exJHEP(2016)·30 citations
21. 21*

    The need for the Higgs boson in the Standard Model

    Jorge C. Romão🇵🇹

    We review the role of the Higgs boson in preserving unitarity of the scattering amplitudes in the Standard Model (SM). We will look at the processes ${\nu }_e+{\bar{\nu }}_e\to W_L^{-}+W_L^{+}$, $W_L^{-}+W_L^{+}\to W_L^{-}+W_L^{+}$ and $e^{-}+e^{+}\to W_L^{-}+W_L^{+}$ for longitudinally polarized gauge bosons. Special emphasis will be put in using algebraic methods to evaluate the amplitudes and cross sections. This note is based on Lectures given at the IDPASC Schools in Udine (2012) and Braga (2014).

    hep-ph12 citations
22. 22*

    Evidence of strong proton shape fluctuations from incoherent diffraction

    Heikki Mäntysaari🇺🇸 · Björn Schenke🇺🇸

    We show within the saturation framework that measurements of exclusive vector meson production at high energy provide evidence for strong geometric fluctuations of the proton. In comparison, the effect of saturation scale and color charge fluctuations is weak. This knowledge will allow detailed future measurements of the incoherent cross section to tightly constrain the fluctuating geometry of the proton as a function of the parton momentum fraction $x$.

    hep-phnucl-thPRL(2016)·248 citations
23. 23*

    Signal of right-handed currents using $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ observables at the kinematic endpoint

    Anirban Karan🇮🇳 · Rusa Mandal🇮🇳 · Abinash Kumar Nayak🇮🇳 · Rahul Sinha🇮🇳 · Thomas E. Browder🇺🇸

    The decay mode $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ is one of the most promising modes to probe physics beyond the standard model (SM), since the angular distribution of the decay products enable measurement of several constraining observables. LHCb has recently measured these observables using $3f{b}^{-1}$ of data as a binned function of $q^2$, the dilepton invariant mass squared. We find that LHCb data implies evidence for right-handed currents, which are absent in the SM. These conclusions are derived in the maximum $q^2$ limit and are free from hadronic corrections. Our approach differs from other approaches that probe new physics at low $q^2$ as it does not require estimates of hadronic parameters but relies instead on heavy quark symmetries that are reliable at the maximum $q^2$ kinematic endpoint.

    hep-phhep-exPRD(2017)·14 citations
24. 24*

    Interpreting the $X(5568)$

    T.J. Burns🇬🇧 · E.S. Swanson🇺🇸

    A variety of options for interpreting the DØ{} state, $X(5568)$, are examined. We find that threshold, cusp, molecular, and tetraquark models are all unfavoured. Several experimental tests for unravelling the nature of the signal are suggested.

    hep-phPLB(2016)·69 citations
25. 25*

    A Proof of the Conformal Collider Bounds

    Diego M. Hofman🇳🇱 · Daliang Li🇺🇸 · David Meltzer🇺🇸 · David Poland🇺🇸 · Fernando Rejon-Barrera🇳🇱

    In this paper, we prove that the "conformal collider bounds" originally proposed by Hofman and Maldacena hold for any unitary parity-preserving conformal field theory (CFT) with a unique stress tensor in spacetime dimensions larger than 2. In particular this implies that the ratio of central charges for a unitary 4d CFT lies in the interval $\frac{31}{18}\ge \frac{a}{c}\ge \frac{1}{3}$. For superconformal theories this is further reduced to $\frac{3}{2}\ge \frac{a}{c}\ge \frac{1}{2}$. The proof relies only on CFT first principles - in particular, bootstrap methods - and thus constitutes the first complete field theory proof of these bounds. We further elaborate on similar bounds for non-conserved currents and relate them to results obtained recently from deep inelastic scattering.

    ↳ hep-thcond-mat.stat-mechcond-mat.str-elhep-phJHEP(2016)·171 citations
26. 26*

    Pionic contribution in the Drell-Yan dilepton production cross section in p-Cu collision in the framework of the shell and Fermi gas models

    R. Rostami🇮🇷 · F. Zolfagharpour🇮🇷

    To investigate the high mass dilepton production cross section produced due to the Drell-Yan process in hadronic collisions such as nucleon- nucleus, the valence and sea quarks distribution functions inside nucleus is used. In this study, in the framework of the shell and Fermi gas models, by adding quarks distribution functions of pions inside nucleus besides the quarks distribution functions of bound nucleons, the changes in the dilepton production cross section were investigated. For this reason, pionic contribution in the structure function of 63Cunucleus and its EMC ratio was first studied using the aforementioned models. Then, in the framework of the Drell-Yan process using GRV's nucleons and pions quarks distribution functions, the high mass dilepton production cross section in p-cu collision was calculated and compared with the available experimental data. The extracted results, based on the two mentioned models, were greatly the same and by considering the pionic contribution, the theoretical results were consistent with the experimental data.

    ↳ nucl-thhep-ph0 citations
27. 27*

    Recommendations on presenting LHC searches for missing transverse energy signals using simplified $s$-channel models of dark matter

    Antonio Boveia🇺🇸 · Oliver Buchmueller🇬🇧 · Giorgio Busoni🇦🇺 · Francesco D'Eramo🇺🇸 · Albert De Roeck🇨🇭 · Andrea De Simone🇮🇹 · Caterina Doglioni🇸🇪 · Matthew J. Dolan🇦🇺 · Marie-Helene Genest🇫🇷 · Kristian Hahn🇺🇸 · Ulrich Haisch🇬🇧 · Philip C. Harris🇨🇭 and 21 other authors

    This document summarises the proposal of the LHC Dark Matter Working Group on how to present LHC results on $s$-channel simplified dark matter models and to compare them to direct (indirect) detection experiments.

    ↳ hep-exhep-phPhys.Dark Univ.(2020)·339 citations
28. 28*

    Rotating Drops of Axion Dark Matter

    Sacha Davidson🇫🇷 · Thomas Schwetz🇩🇪

    We consider how QCD axions produced by the misalignment mechanism could form galactic dark matter halos. We recall that stationary, gravitationally stable axion field configurations have the size of an asteroid with masses of order $10^{-13}$ solar masses (because gradient pressure is insufficient to support a larger object). We call such field configurations "drops". We explore whether rotating drops could be larger, and find that their mass could increase by a factor ~ 10. Remarkably this mass is comparable to the mass of miniclusters generated from misalignment axions in the scenario where the axion is born after inflation. We speculate that misalignment axions today are in the form of drops, contributing to dark matter like a distribution of asteroids (and not as a coherent oscillating background field). We consider some observational signatures of the drops, which seem consistent with a galactic halo made of axion dark matter.

    ↳ astro-ph.COhep-phPRD(2016)·90 citations
29. 29*

    Mass of the b-quark and B-decay constants from Nf=2+1+1 twisted-mass Lattice QCD

    ETM Collaboration: A. Bussone🇩🇰 · N. Carrasco🇮🇹 · P. Dimopoulos🇮🇹 · R. Frezzotti🇮🇹 · P. Lami🇮🇹 · V. Lubicz🇮🇹 · E. Picca🇮🇹 · L. Riggio🇮🇹 · G.C. Rossi🇮🇹 · S. Simula🇮🇹 · C. Tarantino🇮🇹

    We present precise lattice computations for the b-quark mass, the quark mass ratios mb/mc and mb/ms as well as the leptonic B-decay constants. We employ gauge configurations with four dynamical quark flavors, up/down, strange and charm, at three values of the lattice spacing (a ~ 0.06 - 0.09 fm) and for pion masses as low as 210 MeV. Interpolation in the heavy quark mass to the bottom quark point is performed using ratios of physical quantities computed at nearby quark masses exploiting the fact that these ratios are exactly known in the static quark mass limit. Our results are also extrapolated to the physical pion mass and to the continuum limit and read: mb(MSbar, mb) = 4.26(10) GeV, mb/mc = 4.42(8), mb/ms = 51.4(1.4), fBs = 229(5) MeV, fB = 193(6) MeV, fBs/fB = 1.184(25) and (fBs/fB)/(fK/fpi) = 0.997(17).

    ↳ hep-lathep-phPRD(2016)·116 citations
30. 30*

    Role of scalar dibaryon and $f_0(500)$ in the isovector channel of low-energy neutron-proton scattering

    Werner Deinet🇩🇪 · Khaled Teilab🇩🇪 · Francesco Giacosa🇩🇪 · Dirk H. Rischke🇩🇪

    We calculate the total and the differential cross section for $np$ scattering at low energies in the isospin $I=1$ channel within the so-called extended Linear Sigma Model. This model contains conventional (pseudo)scalar and (axial--)vector mesons, as well as the nucleon and its chiral partner within the mirror assignment. In order to obtain good agreement with experimental data analysis results we need to consider two additional resonances: the lightest scalar state $f_0(500)$ and a dibaryon state with quantum numbers $I=1,$ $J^P=0^{+}$ (also known as ${}^1{S}_0$ resonance). The resonance $f_0(500)$ is coupled to nucleons in a chirally invariant way through the mirror assignment and is crucial for a qualitatively correct description of the shape of the differential cross section. On the other hand, the dibaryon is exchanged in the $s$--channel and is responsible of the large cross section close to threshold. We compare our results to data analysis results performed by the SAID program of the CNS Data Analysis Center (in the following "SAID results").

    ↳ nucl-thhep-phPRC(2016)·4 citations
31. 31*

    Electroweak and Majorana Sector Higgs Bosons and Pseudo-Nambu-Goldstone Bosons

    Wei Lu

    We propose a Clifford algebra based model, which treats both gravity and Yang-Mills interactions as gauge fields. There are two sectors of boson fields as electroweak and Majorana bosons. The electroweak boson sector induces fermion masses via spontaneous symmetry breaking. It is composed of scalar Higgs, pseudoscalar Higgs, and antisymmetric tensor components. The Majorana boson sector contributes to flavor mixing and Majorana masses of right-handed neutrinos. It is comprised of neutrino Higgs and pseudo-Nambu-Goldstone bosons. The LHC 750 GeV diphoton resonance might possibly be identified as a Majorana sector pseudo-Nambu-Goldstone boson, which results from spontaneous symmetry breaking of a flavor-related global U(1) symmetry involving four-fermion condensation of right-handed leptons and quarks. The diphoton decay is loop induced, since tree-level decay is suppressed by large Majorana mass of the right-handed neutrino. There is also a potential dark matter candidate, which is the four-lepton condensation of muon, muon-neutrino, tau, and tau-neutrino.

    ↳ physics.gen-phhep-ph6 citations
32. 32*

    Yet another symmetry breaking to be discovered

    M. Yoshimura🇯🇵

    The discovery of spontaneous symmetry breaking in particle physics was the greatest contribution in Nambu's achievements. There is another class of symmetries that exist in the low energy nature, yet is doomed to be broken at high energy, due to a lack of protection of the gauge symmetry. I shall review our approach to search for this class of symmetry breaking, the lepton number violation linked to generation of the matter-antimatter asymmetry in our universe.

    ↳ physics.hist-phhep-phhep-thPTEP(2016)·0 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.