Tue·Apr 10, 2018Tuesday·April 10, 2018

1. 01*

   Gravity Waves and Proton Decay in Flipped SU(5) Hybrid Inflation Model

   Mansoor Ur Rehman🇵🇰 · Qaisar Shafi🇺🇸 · Umer Zubair🇺🇸

   We revisit supersymmetric hybrid inflation in the context of flipped $SU(5)$ model. With minimal superpotential and minimal Kähler potential, and soft SUSY masses of order $(1-100)$ TeV, compatibility with the Planck data yields a symmetry breaking scale $M$ of flipped $SU(5)$ close to $(2-4)\times 10^{15}$ GeV. This disagrees with the lower limit $M\gtrsim 7\times 10^{15}$ GeV set from proton decay searches by the Super-Kamiokande collaboration. We show how $M$ close to the unification scale $2\times 10^{16}$ GeV can be reconciled with SUSY hybrid inflation by employing a non-minimal Kähler potential. Proton decays into $e^{+}{\pi }^0$ with an estimated lifetime of order $10^{36}$ years. The tensor to scalar ratio $r$ in this case can approach observable values $\sim 10^{-4}-10^{-3}$.

   hep-phPRD(2018)·20 citations
2. 02*

   The nonet of the light scalar tetraquarks: the mesons $a_0(980)$ and $K_0^{\ast }(800)$

   S. S. Agaev🇦🇿 · K. Azizi🇹🇷 · H. Sundu🇹🇷

   The spectroscopic parameters and partial decay widths of the light mesons $a_0(980)$ and $K_0^{\ast }(800)$ are calculated by treating them as scalar diquark-antidiquark states. The masses and couplings of the mesons are found in the framework of QCD two-point sum rule approach. The widths of the decay channels $a_0(980)\to \eta \pi$ and $a_0(980)\to K\bar{K}$, and $K_0^{\ast }(800)\to K^{+}{\pi }^{-}$ and $K_0^{\ast }(800)\to K^0{\pi }^0$ are evaluated using QCD sum rules on the light-cone and technical tools of the soft meson approximation. Our results for the mass of the mesons $m_{a_0}=991_{-27}^{+29}\mathrm{MeV}$ and $m_{K^{\ast }}=767_{-29}^{+38}\mathrm{MeV}$, as well as their total width ${\Gamma }_{{\mathrm{a}}_0}=62.01\pm 14.37\mathrm{MeV}$ and ${\Gamma }_{{\mathrm{K}}_0^{\ast }}=401.1\pm 87.1\mathrm{MeV}$ are compared with last experimental data.

   hep-phhep-exhep-latPLB(2019)·25 citations
3. 03*

   CP violation in extended Higgs sectors

   O. M. Ogreid🇳🇴 · P. Osland🇳🇴 · M. N. Rebelo🇵🇹

   We discuss how one can identify CP violation (and conservation) in multi-Higgs-doublet potentials. After a brief review of CP violation in the 2HDM, we refer to the fact that for NHDM with $N\ge 3$ the well known methods useful in the case $N=2$ have not been generalized in order to provide a set of well defined necessary and sufficient conditions for CP conservation. We then present a simple method, proposed by the authors, to be used in such cases. Two non-trivial examples based on an $S_3$-symmetric three-doublet model are analyzed by means of this new method.

   hep-phPoS(2018)·2 citations
4. 04*

   Energy evolution of J/$\psi$ production in DIS on nuclei

   E. Gotsman (Tel Aviv U.)🇮🇱 · E. Levin (Tel Aviv U./UTFSM)🇮🇱

   In this paper we show, that the $J/\psi$ production in DIS, is the main source of information about the events with two parton shower production. We attempt to develop our theoretical acumen of this process, to a level compatible with the theoretical description of inclusive DIS. We revisit the problem of the linear evolution equation for the double gluon densities, and include Bose-Einstein enhancement to these equations. We find that the Bose-Einstein correlations lead to an increase of the anomalous dimension, which turns out to be suppressed as $1/(N_c^2-1{)}^2$, in agreement with the estimates for the twist four anomalous dimension. We believe that understanding what happens to these contributions at ultra high energies, is a key question for an effective theory, based on high energy QCD. We derive the evolution equation for the scattering amplitude of two dipoles with a nucleus, taking into account the shadowing corrections, and investigate the analytical solutions in two distinct kinematic regions: deep in the saturation region, and in the vicinity of the saturation scale. The suggested non-linear evolution equation is a direct generalization of the Balitsky-Kovchegov equation, which has to be solved with the initial condition that depends on the saturation scale $Q_s(Y=Y_0,b)$. With the goal of finding a new small parameter, it is instructive to compare the solution of the non-linear equation with the qusi-classical approximation, in which in the initial condition we replace $Q_s(Y=Y_0,b)$ by $Q_s(Y,b)$. Our final result is that the shadowing corrections in the elastic amplitude generate the survival probability, which suppresses the growth of the amplitude with energy, caused by the Bose-Einstein enhancement.

   hep-phPRD(2018)·3 citations
5. 05*

   Direct signals from electroweak singlets through the Higgs portal

   Rainer Dick🇨🇦

   We review predictions and constraints for nuclear recoil signals from Higgs portal dark matter under the assumption of standard thermal creation from freeze-out. Thermally created scalar and vector Higgs portal dark matter masses are constrained to be in the resonance region near half the Higgs mass or above several TeV. The resonance region for these models will be tested by XENONnT and LZ. The full mass range up to the unitarity limit can be tested by DarkSide-20k and DARWIN. Fermionic Higgs portal dark matter with a pure CP odd coupling is constrained by the Higgs decay width, but has strongly suppressed recoil cross sections which cannot be tested with upcoming experiments. Fermionic Higgs portal dark matter with a combination of CP even and odd Higgs couplings can be constrained by the direct search experiments.

   hep-phInt.J.Mod.Phys.D(2018)·5 citations
6. 06*

   Vector meson dominance in ${\eta }^{\prime }\to {\pi }^0\gamma \gamma$ decay

   Yaroslav Balytskyi🇺🇸

   The decay ${\eta }^{\prime }\to {\pi }^0\gamma \gamma$ is studied theoretically in the framework of the Vector Meson Dominance model (VMD). We find theoretically a significant contribution of the interference of $\omega -\rho$ and provide theoretical Dalitz-plots. Comparison with the experimental results of BES-III \cite{BES-III} is done. We find some tension between our predicted value and the observed result. Our calculations can be also checked using the data of GAMS-$4\pi$.

   hep-ph6 citations
7. 07*

   One-loop renormalized Higgs vertices in Georgi-Machacek model

   Cheng-Wei Chiang🇹🇼 · An-Li Kuo🇹🇼 · Kei Yagyu🇯🇵

   We compute renormalized vertices of the 125 GeV Higgs boson $h$ with the weak gauge bosons ($hVV$), fermions ($hf\bar{f}$) and itself ($hhh$) in the Georgi-Machacek model at one-loop level. The renormalization is performed based on the on-shell scheme with the use of the minimal subtraction scheme only for the $hhh$ vertex. We explicitly show the gauge dependence in the counterterms of the scalar mixing parameters in the general $R_{\xi }$ gauge, and that the dependence can be removed by using the pinch technique in physical scattering processes. We then discuss the possible allowed deviations in these one-loop corrected Higgs couplings from the standard model predictions by scanning model parameters under the constraints of perturbative unitarity and vacuum stability as well as those from experimental data.

   hep-phPRD(2018)·48 citations
8. 08*

   Properties of the Free Energy Density Using the Principle of Maximum Conformality

   Shi Bu🇨🇳 · Xing-Gang Wu · Jian-Ming Shen🇨🇳 · Jun Zeng🇨🇳

   We present a detailed study on the properties of the free energy density at the high temperature by applying the principle of maximum conformality (PMC) scale-setting method within the effective field theory. The PMC utilizes the renormalization group equation recursively to identify the occurrence and pattern of the non-conformal $\{{\beta }_i\}$-terms, and determines the optimal renormalization scale at each order. Our analysis shows that a more accurate free energy density up to $g_s^5$-order level without renormalization scale dependence can be achieved by applying the PMC. We also observe that by using a smaller factorization scale around the effective parameter $m_E$, the PMC prediction shall be consistent with the Lattice QCD prediction derived at the low temperature.

   hep-phCPC(2018)·0 citations
9. 09*

   Analysis of the structure of $\Xi (1690)$ through its decays

   T. M. Aliev🇹🇷 · K. Azizi🇹🇷 · H. Sundu🇹🇷

   The mass and pole residue of the first orbitally and radially excited $\Xi$ state as well as the ground state residue are calculated by means of the two-point QCD sum rules. Using the obtained results for the spectroscopic parameters, the strong coupling constants relevant to the decays $\Xi (1690)\to \Sigma K$ and $\Xi (1690)\to \Lambda K$ are calculated within the light-cone QCD sum rules and width of these decay channels are estimated. The obtained results for the mass of $\tilde{\Xi }$ and ratio of the $Br(\tilde{\Xi }\to \Sigma K)/Br(\tilde{\Xi }\to \Lambda K)$, with $\tilde{\Xi }$ representing the orbitally excited state in $\Xi$ channel, are in nice agreement with the experimental data of the Belle Collaboration. This allows us to conclude that the $\Xi (1690)$ state, most probably, has negative parity.

   hep-phhep-exhep-latEPJC(2018)·9 citations
10. 10*

    Freeze-In Dark Matter from a sub-Higgs Mass Clockwork Sector via the Higgs Portal

    Jinsu Kim🇰🇷 · John McDonald🇬🇧

    The clockwork mechanism allows extremely weak interactions and small mass scales to be understood in terms of the structure of a theory. A natural application of the clockwork mechanism is to the freeze-in mechanism for dark matter production. Here we consider a Higgs portal freeze-in dark matter model based on a scalar clockwork sector with a mass scale which is less than the Higgs boson mass. The dark matter scalar is the lightest scalar of the clockwork sector. Freeze-in dark matter is produced by the decay of thermal Higgs bosons to the clockwork dark matter scalars. We show that the mass of the dark matter scalar is typically in the 1-10 keV range and may be warm enough to have an observable effect on perturbation growth and Lyman-$\alpha$ observations. Clockwork Higgs portal freeze-in models have a potentially observable collider phenomenology, with the Higgs boson decaying to missing energy in the form of pairs of long-lived clockwork sector scalars, plus a distribution of different numbers of quark and lepton particle-antiparticle pairs. The branching ratio to different numbers of quark and lepton pairs is determined by the clockwork sector parameters (the number of clockwork scalars $N$ and the clockwork charge $q$), which could therefore be determined experimentally if such Higgs decay modes are observed. In the case of a minimal Standard Model observable sector, the combination of nucleosynthesis and Lyman-$\alpha$ constraints is likely to exclude on-shell Higgs decays to clockwork scalars, although off-shell Higgs decays would still be possible. On-shell Higgs decays to clockwork scalars can be consistent with cosmological constraints in simple extensions of the Standard Model with light singlet scalars.

    hep-phastro-ph.COPRD(2018)·26 citations
11. 11*

    Charm quarks are more hydrodynamic than light quarks in final-state elliptic flow

    Hanlin Li🇨🇳 · Zi-Wei Lin🇺🇸 · Fuqiang Wang🇺🇸

    We study the charm quark elliptic flow ($v_2$) in heavy ion as well as small system collisions by tracking the evolution history of quarks of different flavors within a multi-phase transport model. The charm quark $v_2$ is studied as a function of the number of collisions the charm quark suffers with other quarks and then compared to the $v_2$ of lighter quarks. We find that the common escape mechanism is at work for both the charm and light quark $v_2$. However, contrary to the naive expectation, the hydrodynamics-type flow is found to contribute more to the final state charm $v_2$ than light quark $v_2$. This could be explained by the smaller average deflection angle the heavier charm quark undergoes in each collision, so that heavy quarks need more scatterings to accumulate a significant $v_2$, while lighter quarks can more easily change directions with scatterings with their $v_2$ coming more from the escape mechanism. Our finding thus suggests that the charm $v_2$ is a better probe for studying the hydrodynamic properties of the quark-gluon plasma.

    hep-phnucl-exnucl-thPRC(2019)·25 citations
12. 12*

    Momentum Sum Rule Violation in QCD at High Energy Colliders and Confinement

    Gouranga C Nayak🇺🇸

    Momentum sum rule in QCD is widely used at high energy colliders. Although the exact form of the confinement potential energy is not known but the confinement potential energy at large distance $r$ can not rise slower than $\ln (r)$. In this paper we find that if the confinement potential energy at large distance $r$ rises linearly with $r$ (or faster) then the momentum sum rule in QCD is violated at the high energy colliders if we consider the hadron size as infinite. For finite size hadron we find that the momentum sum rule in QCD is violated at the high energy colliders for any form of the confinement potential energy.

    hep-phhep-latnucl-th5 citations
13. 13*

    QFT derivation of the decay law of an unstable particle with nonzero momentum

    Francesco Giacosa🇵🇱

    We present a quantum field theoretical derivation of the nondecay probability of an unstable particle with nonzero three-momentum $\mathbf{p}$. To this end, we use the (fully resummed) propagator of the unstable particle, denoted as $S,$ to obtain the energy probability distribution, called $d_S^{\mathbf{p}}(E)$, as the imaginary part of the propagator. The nondecay probability amplitude of the particle $S$ with momentum $\mathbf{p}$ turns out to be, as usual, its Fourier transform: $a_S^{\mathbf{p}}(t)={\int }_{\sqrt{m_{th}^2+{\mathbf{p}}^2}}^{\infty }dE{d}_S^{\mathbf{p}}(E)e^{-iEt}$ ($m_{th}$ is the lowest energy threshold in the energy frame, corresponding to the sum of masses of the decay products). Upon a variable transformation, one can rewrite it as $a_S^{\mathbf{p}}(t)={\int }_{m_{th}}^{\infty }dm{d}_S^0(m)e^{-i\sqrt{m_{th}^2+{\mathbf{p}}^2}t}$ [here, $d_S^0(m)\equiv d_S(m)$ is the usual spectral function (or mass distribution) in the rest frame]. Hence, the latter expression, previously obtained by different approaches, is here confirmed in an independent and, most importantly, covariant QFT-based approach. Its consequences are not yet fully explored but appear to be quite surprising (such as the fact that usual time-dilatation formula does not apply), thus its firm understanding and investigation can be a fruitful subject of future research.

    hep-phhep-thquant-phAdv.High Energy Phys.(2018)·17 citations
14. 14*

    Degeneracy resolution capabilities of NO$\nu$A and DUNE in the presence of light sterile neutrino

    Akshay Chatla🇮🇳 · Sahithi Rudrabhatla🇺🇸 · Bindu A. Bambah🇮🇳

    We investigate the implications of a sterile neutrino on the physics potential of the proposed experiment DUNE and future runs of NO$\nu$A using latest NO$\nu$A results. Using combined analysis of the disappearance and appearance data, NO$\nu$A reported preferred solutions at normal hierarchy (NH) with two degenerate best-fit points one in the lower octant (LO) and ${\delta }_{13}$ = 1.48$\pi$ and other in higher octant (HO) and ${\delta }_{13}$ = 0.74$\pi$. Another solution of inverted hierarchy (IH) which is 0.46$\sigma$ away from best fit was also reported. We discuss chances of resolving these degeneracies in the presence of sterile neutrino.

    hep-phAdv.High Energy Phys.(2018)·11 citations
15. 15*

    Constraints on $Wtb$ anomalous coupling with $B\to X_s\gamma$ and $B_{s}\to\mu^{+}\mu^{-}

    Zhao-Hua Xiong🇨🇳 · Lian Zhou🇨🇳

    We calculate the amplitudes of $b\to s$ transition in extension of the Standard Model with $Wtb$ anomalous couplings. We found that i) there exist the Ward identity violating terms in effective vertix of $b\to s\gamma$. The terms, which come from the tensor parts of $Wtb$ anomalies, and can be canceled exactly by introducing corresponding $Wtb\gamma$ interactions, ii) $Br(B_s\to {\mu }^{+}{\mu }^{-})$ provides unique information on $\delta v_L$ which is set to zero in top decay experiments, and stringent bounds on $v_R,g_L$ by $Br(B\to X_s\gamma )$ are obtained.

    hep-ph1 citation
16. 16*

    Searching for Vector-Like Quarks in a Fermionic Dark Matter Model with Pseudoscalar: A Resonance Case

    Seyed Yaser Ayazi🇮🇷 · Ahmad Mohamadnejad🇮🇷 · S. Peyman Zakeri🇮🇷

    We propose a minimal model of a fermionic dark matter with a pseudoscalar mediator and N generation of vector-like quarks. We calculate the relic density and obtain new constraint on the generation of the aforementioned quarks. Concerning phenomenological aspects, we probe the presenting model via direct and indirect approaches. Finally, as an illustrative example, we evaluate a resonance case which has been (would be) the subject of major experiments aiming to detect new particles. Performing this analysis results in significant constraints on the coupling strength of the vector-like quarks.

    hep-phMod.Phys.Lett.A(2018)·3 citations
17. 17*

    Spinor Calculus in Particle Physics

    Christian Carimalo

    Methods of spinor calculus in particle physics are described in this series of four chapters written in french. A special emphasis is made on the well-known helicity-coupling scheme which is the guiding thread of all these methods. Numerous explicit formulas are given for projectors onto two-particles helicity states as well as for bilinears of Dirac spinors, for the s and t channels of a given two-body process involving spin 1/2 particles. In the last chapter, applications to various elementary processes are given.

    hep-ph0 citations
18. 18*

    Correlations and the ridge in the Color Glass Condensate beyond the glasma graph approximation

    Tolga Altinoluk🇵🇱 · Néstor Armesto🇪🇸 · Douglas E. Wertepny🇪🇸

    We consider two-gluon production in dilute-dense collisions within the Color Glass Condensate framework, applicable to both proton-nucleus and heavy-light ion collisions. We go beyond the glasma graph approximation which is valid in the dilute-dilute limit and show the correspondence between the glasma graphs and the $k_T$-factorized approach that we use in our calculation. We then identify the classical uncorrelated, and the Hanbury-Brown-Twiss (HBT) and Bose enhancement correlated contributions, with the Bose enhancement contribution being suppressed by the number of degrees of freedom with respect to the uncorrelated piece. We show that both the HBT and the Bose enhancement pieces survive the inclusion of higher order contributions in density and that they stem from the quadrupole piece of the two-gluon inclusive cross section. Finally, we illustrate the results using a toy model that allows a simple numerical implementation.

    hep-phnucl-thJHEP(2018)·24 citations
19. 19*

    Strong field QED in lepton colliders and electron/laser interactions

    Anthony Hartin🇬🇧

    Studies of strong field particle physics processes in electron/laser interactions and lepton collider interaction points are reviewed. These processes are defined by the high intensity of the electromagnetic fields involved and the need to take them into account as fully as possible. The main theoretical framework considered is the Furry picture. In this framework, the influence of a background electromagnetic field in the Lagrangian is calculated non perturbatively, involving exact solutions for quantised charged particles in the background field. These "dressed" particles go on to interact perturbatively with other particles. The background field starts to polarise the vacuum, in effect rendering it a dispersive medium. Particles encountering this dispersive vacuum obtain a lifetime, either radiating or decaying into pair particles at a rate dependent on the intensity of the background field. In fact, the intensity of the background field enters into the coupling constant of the strong field QED Lagrangian, influencing all particle processes. A number of new phenomena occur. Particles gain an intensity dependent rest mass shift that accounts for their presence in the dispersive vacuum. Multi photon events involving more than one external field photon occur at each vertex. Higher order processes which exchange a virtual strong field particle, resonate via the lifetimes of the unstable strong field states. Two main arenas of strong field physics are reviewed; those occurring in relativistic electron interactions with intense laser beams, and those occurring in the beam beam physics at the interaction point of colliders. This review outlines the theory, describes its significant novel phenomenology and details the experimental schema required to detect strong field effects and the simulation programs required to model them.

    hep-phInt.J.Mod.Phys.A(2018)·53 citations
20. 20*

    B $\to f_2(1270)$ form factors with light-cone sum rules

    Maximilian Emmerich🇩🇪 · Matthias Strohmaier🇩🇪 · Andreas Schäfer🇩🇪

    We construct the quark-antiquark chiral odd distribution amplitudes including twist-four mass contributions for tensor mesons. We also give quark-antiquark-gluon distribution amplitudes, where we calculate the input parameters with QCD sum rules. With the help of equations of motion we determine the twist-three and twist-four distribution amplitudes including SU(3) breaking terms. We use QCD light-come sum rules to derive the form factors for the decay B $\to f_2(1270)$ with vector, axial-vector and tensor currents. We also give the $q^2$ dependence of the form factors.

    hep-phnucl-thPRD(2018)·5 citations
21. 21*

    Exotic triple-charm deuteron-like hexaquarks

    Rui Chen🇨🇳 · Fu-Lai Wang🇨🇳 · Atsushi Hosaka🇯🇵 · Xiang Liu🇨🇳

    Adopting the one-boson-exchange model, we perform a systematic investigation of interactions between a doubly charmed baryon $({\Xi }_{cc})$ and an $S$-wave charmed baryon (${\Lambda }_c$, ${\Sigma }_c^{(\ast )}$, and ${\Xi }_c^{(\prime ,\ast )}$). Both the $S$-$D$ mixing effect and coupled-channel effect are considered in this work. Our results suggest that there may exist several possible triple-charm deuteron-like hexaquarks. Meanwhile, we further study the interactions between a doubly charmed baryon and an $S$-wave anticharmed baryon. We find that a doubly charmed baryon and an $S$-wave anticharmed baryon can be easily bound together to form shallow molecular hexaquarks. These heavy flavor hexaquarks predicted here can be accessible at future experiment like LHCb.

    hep-phPRD(2018)·39 citations
22. 22*

    Constraints on Dark Matter with a moderately large and velocity-dependent DM-nucleon cross-section

    M. Shafi Mahdawi🇺🇸 · Glennys R. Farrar🇺🇸

    We derive constraints on a possible velocity-dependent DM-nucleon scattering cross section, for Dark Matter in the 10 MeV -- 100 GeV mass range, using the XQC, DAMIC, and CRESST 2017 Surface Run experiments. We report the limits on cross sections of the form $\sigma ={\sigma }_0{v}^n$, for a range of velocity dependencies with $n\in \{-4,-2,-1,0,1,2\}$. We point out the need to measure the efficiency with which nuclear recoil energy in the sub-keV range thermalizes, rather than being stored as Frenkel pairs in the semi-conductor lattice. The possibility of a significant inefficiency leaves open a considerable `hole' in the limits for mass in the $\sim$ 0.2 -- 2 GeV range, which XQC and CRESST can potentially fill when the thermalization efficiency is measured. We call attention to the asymmetry between a conventional lower limit cross section and the `upper-reach cross section' imposed by attenuation in an overburden -- an upper boundary being extremely sharp but quite insensitive to the statistics of the experiment. Considering the recent interest to use dark matter-baryon interaction with velocity dependence $n=-4$ to explain the EDGES 21 cm anomaly, we also derive the limits on milli-charged DM that scatters off protons and electrons under a Coulomb-like interaction. We find that much but not all of the region of interest for the EDGES anomaly can be excluded.

    hep-phastro-ph.COastro-ph.HEhep-exJCAP(2018)·112 citations
23. 23*

    Multi-Higgs models with CP symmetries of increasingly high order

    Igor P. Ivanov🇵🇹 · Maxim Laletin🇧🇪

    When building CP-symmetric models beyond the Standard Model, one can impose CP-symmetry of higher order. This means that one needs to apply the CP-transformation more than two times to get the identity transformation, but still the model is perfectly CP-conserving. A multi-Higgs-doublet model based on CP-symmetry of order 4, dubbed CP4, was recently proposed and its phenomenology is being explored. Here, we show that the construction does not stop at CP4. We build examples of renormalizable multi-Higgs-doublet potentials which are symmetric under CP8 or CP16, without leading to any accidental symmetry. If the vacuum conserves CP-symmetry of order 2k, then the neutral scalars become CP-eigenstates, which are characterized not by CP-parities but by CP-charges defined modulo 2k. One or more lightest states can be the dark matter candidates, which are protected against decay not by the internal symmetry but by the exotic CP. We briefly discuss their mass spectra and interaction patterns for CP8 and CP16.

    hep-phPRD(2018)·16 citations
24. 24*

    Baryon masses and \sigma-terms in SU(3) BChPT x 1/Nc

    I. P. Fernando🇺🇸 · J. M. Alarcon🇺🇸 · J. L. Goity🇺🇸

    Baryon masses and nucleon \sigma-terms are studied with the effective theory that combines the chiral and 1/Nc expansions for three flavors. In particular the connection between the deviation of the Gell-Mann-Okubo relation and the \sigma-term corresponding to the scalar density associated with the hypercharge is emphasized. The latter is at lowest order related to a mass combination whose low value has given rise to a \sigma- term puzzle. It is shown that while the nucleon \sigma-terms have a well behaved low energy expansion, that mass combination is affected by large higher order corrections non-analytic in quark masses. Adding to the analysis lattice QCD baryon masses, it is found that {\sigma}{\pi}N=69(10) MeV and {\sigma}s has natural magnitude within its relative large uncertainty.

    hep-phPLB(2018)·13 citations
25. 25*

    Atomic Physics Constraints on the X Boson

    Ulrich D. Jentschura🇺🇸 · Istvan Nandori🇭🇺

    Recently, a peak in the light fermion pair spectrum at invariant q^2 approximately equal to 16.7 Me^2. has been observed in the bombardment of Li-7 by protons. This peak has been interpreted in terms of a protophobic interaction of fermions with a gauge boson (X boson) of invariant mass of approximately 16.7 MeV which couples mainly to neutrons. High-precision atomic physics experiments aimed at observing the protophobic interaction need to separate the X boson effect from the nuclear-size effect, which is a problem because of the short range of the interaction 11.8 fm, which is commensurate with a "nuclear halo". Here, we analyze the X boson in terms of its consequences for both electronic atoms as well as muonic hydrogen and deuterium. We find that the most promising atomic systems where the X boson has an appreciable effect, distinguishable from a finite-nuclear-size effect, are muonic atoms of low and intermediate nuclear charge numbers.

    hep-phPRA(2018)·15 citations
26. 26*

    The Variable Flavor Number Scheme at Next-to-Leading Order

    J. Blümlein🇩🇪 · A. De Freitas🇩🇪 · C. Schneider🇦🇹 · K. Schönwald🇩🇪

    We present the matching relations of the variable flavor number scheme at next-to-leading order, which are of importance to define heavy quark partonic distributions for the use at high energy colliders such as Tevatron and the LHC. The consideration of the two-mass effects due to both charm and bottom quarks, having rather similar masses, are important. These effects have not been considered in previous investigations. Numerical results are presented for a wide range of scales. We also present the corresponding contributions to the structure function $F_2(x,Q^2)$.

    hep-phhep-exPLB(2018)·45 citations
27. 27*

    M${}^3$: A New Muon Missing Momentum Experiment to Probe $(g-2{)}_{\mu }$ and Dark Matter at Fermilab

    Yonatan Kahn🇺🇸 · Gordan Krnjaic🇺🇸 · Nhan Tran🇺🇸 · Andrew Whitbeck🇺🇸

    New light, weakly-coupled particles are commonly invoked to address the persistent $\sim 4\sigma$ anomaly in $(g-2{)}_{\mu }$ and serve as mediators between dark and visible matter. If such particles couple predominantly to heavier generations and decay invisibly, much of their best-motivated parameter space is inaccessible with existing experimental techniques. In this paper, we present a new fixed-target, missing-momentum search strategy to probe invisibly decaying particles that couple preferentially to muons. In our setup, a relativistic muon beam impinges on a thick active target. The signal consists of events in which a muon loses a large fraction of its incident momentum inside the target without initiating any detectable electromagnetic or hadronic activity in downstream veto systems. We propose a two-phase experiment, M${}^3$ (Muon Missing Momentum), based at Fermilab. Phase 1 with $\sim 10^{10}$ muons on target can test the remaining parameter space for which light invisibly-decaying particles can resolve the $(g-2{)}_{\mu }$ anomaly, while Phase 2 with $\sim 10^{13}$ muons on target can test much of the predictive parameter space over which sub-GeV dark matter achieves freeze-out via muon-philic forces, including gauged $U(1{)}_{L_{\mu }-L_{\tau }}$.

    hep-phastro-ph.COhep-exphysics.ins-detJHEP(2018)·174 citations
28. 28*

    Radio Signals from Axion Dark Matter Conversion in Neutron Star Magnetospheres

    Anson Hook🇺🇸 · Yonatan Kahn🇺🇸 · Benjamin R. Safdi🇺🇸 · Zhiquan Sun🇺🇸

    We show that axion dark matter (DM) may be detectable through narrow radio lines emitted from neutron stars. The neutron star magnetosphere hosts a strong magnetic field and a plasma frequency that increases towards the neutron star surface. As the axions pass through the magnetosphere, they can resonantly convert into radio photons in a narrow region around the radius at which the plasma frequency equals the axion mass. The bandwidth of the signal is set by the small DM velocity dispersion far away from the neutron star. We solve the axion-photon mixing equations, including a full treatment of the magnetized plasma and associated anisotropic dielectric tensor, to obtain the conversion probability. We discuss possible neutron-star targets and how they may probe the QCD axion parameter space in the mass range of ~0.2-40 $\mu$eV.

    hep-phastro-ph.COastro-ph.HEPRL(2018)·225 citations
29. 29*

    Extended supersymmetry in Dirac action with extra dimensions

    Yukihiro Fujimoto🇯🇵 · Kouhei Hasegawa🇯🇵 · Kenji Nishiwaki🇰🇷 · Makoto Sakamoto🇯🇵 · Kentaro Tatsumi🇯🇵 · Inori Ueba🇯🇵

    We investigate a new realization of extended quantum-mechanical supersymmetry. We first show that an $\mathcal{N}=2$ quantum-mechanical supersymmetry is hidden in the four-dimensional (4D) spectrum of the Kaluza-Klein decomposition for the higher dimensional Dirac field, that is, Kaluza-Klein mode functions of 4D right-handed spinors and 4D left-handed ones form $\mathcal{N}=2$ supermultiplets. In addition to $\mathcal{N}=2$ supersymmetry, we discover that an $\mathcal{N}$-extended supersymmetry ($\mathcal{N}=d+2(d+1)$ for $d=$ even (odd) extra dimensions) is further hidden in the 4D spectrum. The extended symmetry can explain additional degeneracy of the spectrum. Furthermore, we show that a superpotential can be introduced into the $\mathcal{N}$-extended supercharges and clarify the condition to preserve the supersymmetry. The partial breaking of the supersymmetry is also demonstrated.

    ↳ hep-thhep-phquant-phJ.Phys.A(2018)·3 citations
30. 30*

    A critical examination of constraints on the equation of state of dense matter obtained from GW170817

    I. Tews🇺🇸 · J. Margueron🇺🇸 · S. Reddy🇺🇸

    The correlation of the tidal polarizabilities ${\Lambda }_1$-${\Lambda }_2$ for GW170817 is predicted by combining dense-matter equations of state (EOSs) that satisfy nuclear physics constraints with the chirp mass and mass asymmetry for this event. Our models are constrained by calculations of the neutron-matter EOS using chiral effective field theory Hamiltonians with reliable error estimates up to once or twice the nuclear saturation density. In the latter case, we find that GW170817 does not improve our understanding of the EOS. We contrast two distinct extrapolations to higher density: a minimal model (MM) which assumes that the EOS is a smooth function of density described by a Taylor expansion and a more general model parametrized by the speed of sound that admits phase transitions. This allows us to identify regions in the ${\Lambda }_1$-${\Lambda }_2$ plots that could favor the existence of new phases of matter in neutron stars. We predict the combined tidal polarizability of the two neutron stars in GW170817 to be $80\le \tilde{\Lambda }\le 580$ ($280\le \tilde{\Lambda }\le 480$ for the MM), which is smaller than the range suggested by the LIGO-Virgo data analysis. Our analysis also shows that GW170817 requires a NS with $M=1.4M_{\odot }$ to have a radius $9.0<R_{1.4}<13.6$~km ($11.3<R_{1.4}<13.6$~km for the MM).

    ↳ nucl-thastro-ph.HEhep-phPRC(2018)·363 citations
31. 31*

    Bhabha scattering at ILC250

    Francois Richard🇫🇷

    This note intends to give an estimate on the sensitivity of the channel ee to ee at the future ILC250. At variance with other two fermion processes, the so-called Bhabha process is influenced by t-channel Z/photon exchange. In spite of the complexity of the resulting angular distribution of this process, one observes a good sensitivity to Zprime exchange, similar to those observed in annihilation channels. This feature is illustrated within the gauge-Higgs unification model, GHU, which shows an impressive indirect sensitivity to the mass of Zprime particles, up to about 20 TeV for the leptonic channels. Beam longitudinal polarisation and high luminosity are the key ingredients for this result. Measuring the Zprime ee coupling with the Bhabha process allows to measure separately Zprimemumu and Zprimetautau coupling, which serves for a precise test of lepton universality. Zprimebb and Zprimett couplings show good sensitivities to GHU. LHC and HE-LHC sensitivities are also discussed.

    ↳ hep-exhep-ph12 citations
32. 32*

    Resolution of the small scale structure issues with dissipative dark matter from multiple Standard Model sectors

    R. Foot🇦🇺

    Dissipative dark matter arising from a hidden sector consisting of $N_{\sec }$ exact copies of the Standard Model is discussed. The particles from each sector interact with those from the other sectors by gravity and via the kinetic mixing interaction, described by the dimensionless parameter, $ϵ$. It has been known for some time that models of this kind are consistent with large scale structure and the cosmic microwave background measurements. Here, we argue that such models can potentially explain various observations on small scales, including the observed paucity and planar distribution of satellite galaxies, the flat velocity function of field galaxies, and the structure of galaxy halos. The value of the kinetic mixing parameter is estimated to be $ϵ\approx 1.2\times 10^{-10}$ for $N_{\sec }=5$, the example studied in most detail here. We also comment on cluster constraints such as those which arise from the Bullet cluster.

    ↳ astro-ph.GAhep-phPRD(2018)·12 citations
33. 33*

    Reconstructing the impact parameter of proton-nucleus and nucleus-nucleus collisions

    Rudolph Rogly🇫🇷 · Giuliano Giacalone🇫🇷 · Jean-Yves Ollitrault🇫🇷

    In proton-nucleus and nucleus-nucleus collision experiments, one determines the centrality of a collision according to the multiplicity or energy deposited in a detector. This serves as a proxy for the true collision centrality, as defined by the impact parameter. We show that the probability distribution of impact parameter in a given bin of experiment-defined centrality can be reconstructed without assuming any specific model for the collision dynamics, in both proton-nucleus and nucleus-nucleus systems. The reconstruction is reliable up to about 10\% centrality, and is more accurate for nucleus-nucleus collisions. We perform an application of our procedure to experimental data from all the CERN Large Hadron Collider (LHC) collaborations, from which we extract, in Pb+Pb and $p$+Pb collisions, the corresponding distributions of impact parameter.

    ↳ nucl-thhep-phnucl-exPRC(2018)·38 citations
34. 34*

    Higher-Point Positivity

    Venkatesa Chandrasekaran🇺🇸 · Grant N. Remmen🇺🇸 · Arvin Shahbazi-Moghaddam🇺🇸

    We consider the extension of techniques for bounding higher-dimension operators in quantum effective field theories to higher-point operators. Working in the context of theories polynomial in $X=(\partial \varphi {)}^2$, we examine how the techniques of bounding such operators based on causality, analyticity of scattering amplitudes, and unitarity of the spectral representation are all modified for operators beyond $(\partial \varphi {)}^4$. Under weak-coupling assumptions that we clarify, we show using all three methods that in theories in which the coefficient ${\lambda }_n$ of the $X^n$ term for some $n$ is larger than the other terms in units of the cutoff, ${\lambda }_n$ must be positive (respectively, negative) for $n$ even (odd), in mostly-plus metric signature. Along the way, we present a first-principles derivation of the propagator numerator for all massive higher-spin bosons in arbitrary dimension. We remark on subtleties and challenges of bounding $P(X)$ theories in greater generality. Finally, we examine the connections among energy conditions, causality, stability, and the involution condition on the Legendre transform relating the Lagrangian and Hamiltonian.

    ↳ hep-thhep-phJHEP(2018)·46 citations
35. 35*

    Measuring the supernova unknowns at the next-generation neutrino telescopes through the diffuse neutrino background

    Klaes Moller🇩🇰 · Anna M. Suliga🇩🇰 · Irene Tamborra🇩🇰 · Peter B. Denton (Niels Bohr Institute)🇩🇰

    The detection of the diffuse supernova neutrino background (DSNB) will preciously contribute to gauge the properties of the core-collapse supernova population. We estimate the DSNB event rate in the next-generation neutrino detectors, Hyper-Kamiokande enriched with Gadolinium, JUNO, and DUNE. The determination of the supernova unknowns through the DSNB will be heavily driven by Hyper-Kamiokande, given its higher expected event rate, and complemented by DUNE that will help in reducing the parameters uncertainties. Meanwhile, JUNO will be sensitive to the DSNB signal over the largest energy range. A joint statistical analysis of the expected rates in 20 years of data taking from the above detectors suggests that we will be sensitive to the local supernova rate at most at a 20-33% level. A non-zero fraction of supernovae forming black holes will be confirmed at a 90% CL, if the true value of that fraction is larger than 20%. On the other hand, the DSNB events show extremely poor statistical sensitivity to the nuclear equation of state and mass accretion rate of the progenitors forming black holes.

    ↳ astro-ph.HEhep-exhep-phJCAP(2018)·101 citations
36. 36*

    Confinement Admits Chiral Symmetry Breaking via Bag

    Hai-Jhun Wang🇨🇳 · Hong Wang🇨🇳

    In this paper, it is pointed out for the first time that the linear effective potential between quarks is intrinsically relating to the bag model while concerning the asymptotically-free nature of colours. Based on the relationship we employ the symmetry method to analyze the quark-anti-quark system. For the tight bound system, one of the quark and anti-quark becomes the bag itself. By imposing the Poincare invariance on the quark-anti-quark bound-state, and translating the chiral transformation to its spatial manifestation, we can infer why the chiral symmetry breaking happens. Applying this knowledge to deep inelastic scattering we reach the conclusion that the measured proton spin in scattering experiments should be uncertain quantity.

    ↳ physics.gen-phhep-ph0 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.