Tue·Apr 25, 2017Tuesday·April 25, 2017

1. 01*

   Pseudo-Majoron as Light Mediator of Singlet Scalar Dark Matter

   Ernest Ma🇺🇸 · Markos Maniatis🇨🇱

   In the singlet-triplet majoron model of neutrino mass, lepton number is spontaneously broken. If it is also softly broken, then a naturally light pseudoscalar particle ${\eta }_I$ exists. It may then act as a light mediator for a real singlet scalar $\chi$ with odd dark parity. It is itself unstable, but decays dominantly to two neutrinos through its triplet scalar component, thereby not disturbing the cosmic microwave background (CMB). It also mixes with the standard-model Higgs boson only in one loop, thereby not contributing significantly to the elastic scattering of $\chi$ off nuclei in dark-matter direct-search experiments.

   hep-phJHEP(2017)·13 citations
2. 02*

   The analysis of the charmonium-like states $X^{\ast }(3860)$,$X(3872)$, $X(3915)$, $X(3930)$ and $X(3940)$ according to its strong decay behaviors

   Guo Liang Yu🇨🇳 · Zhi Gang Wang🇨🇳 · Zhen Yu Li🇨🇳

   Inspired by the newly observed state $X^{\ast }(3860)$, we analyze the strong decay behaviors of some charmonium-like states $X^{\ast }(3860)$,$X(3872)$, $X(3915)$, $X(3930)$ and $X(3940)$ by the ${}^3{P}_0$ model. We carry out our work based on the hypothesis that these states are all being the charmonium systems. Our analysis indicates that $0^{++}$ charmonium state can be a good candidate for $X^{\ast }(3860)$ and $1^{++}$ state is the possible assignment for $X(3872)$. Considering as the $3^1{S}_0$ state, the decay behavior of $X(3940)$ is inconsistent with the experimental data. So, we can not assign $X(3940)$ as the $3^1{S}_0$ charmonium state by present work. Besides, our analysis imply that it is reasonable to assign $X(3915)$ and $X(3930)$ to be the same state, $2^{++}$. However, combining our analysis with that of Zhou~\cite{ZhouZY}, we speculate that $X(3915)$/$X(3930)$ might not be a pure $c\overline{c}$ systems.

   hep-phCPC(2018)·20 citations
3. 03*

   Search for domain wall dark matter with atomic clocks on board global positioning system satellites

   Benjamin M. Roberts🇺🇸 · Geoffrey Blewitt🇺🇸 · Conner Dailey🇺🇸 · Mac Murphy🇺🇸 · Maxim Pospelov🇨🇦 · Alex Rollings🇺🇸 · Jeff Sherman🇺🇸 · Wyatt Williams🇺🇸 · Andrei Derevianko🇺🇸

   Cosmological observations indicate that 85% of all matter in the Universe is dark matter (DM), yet its microscopic composition remains a mystery. One hypothesis is that DM arises from ultralight quantum fields that form macroscopic objects such as topological defects. Here we use GPS as a ~ 50,000 km aperture DM detector to search for such defects in the form of domain walls. GPS navigation relies on precision timing signals furnished by atomic clocks hosted on board GPS satellites. As the Earth moves through the galactic DM halo, interactions with topological defects could cause atomic clock glitches that propagate through the GPS satellite constellation at galactic velocities ~ 300 km/s. Mining 16 years of archival GPS data, we find no evidence for DM in the form of domain walls at our current sensitivity level. This allows us to improve the limits on certain quadratic scalar couplings of domain wall DM to standard model particles by several orders of magnitude.

   hep-phastro-ph.COastro-ph.HEphysics.atom-phNature Commun.(2017)·112 citations
4. 04*

   Electroweak Vacuum Instability and Renormalized Vacuum Field Fluctuations in Friedmann-Lemaitre-Robertson-Walker Background

   Kazunori Kohri🇯🇵 · Hiroki Matsui🇯🇵

   The cosmological Higgs vacuum stability has been an attractive research subject and it is crucial to accurately follow the development of the Higgs fluctuations. In this work, we thoroughly investigate how the vacuum fluctuations of the Higgs field affect the stability of the electroweak vacuum in Friedmann-Lemaitre-Robertson-Walker (FLRW) background. Adopting adiabatic (WKB) approximation or adiabatic regularization methods, we clearly show that vacuum fluctuations of the Higgs field in the FLRW background depend on the curvature and also masses of the Higgs or other scalar fields. The Higgs fluctuations can generate true vacuum bubbles and trigger off a collapse of the electroweak vacuum. Furthermore we clearly show that the effective Higgs potential in the FLRW background is modified by the Higgs vacuum fluctuations. The vacuum fluctuations of the standard model fields can stabilize or destabilize the effective Higgs potential through backreaction effects. Considering the improved effective Higgs potential with the Higgs vacuum fluctuations $⟨{\delta \varphi }^2⟩$ in various backgrounds, we provide new cosmological constraints on the mass of the Higgs-coupled scalar fields and a quantitative description of the Higgs stability in the FLRW background.

   hep-phastro-ph.COgr-qchep-thPRD(2018)·23 citations
5. 05*

   Quarkonium as relativistic bound state on the light front

   Yang Li🇺🇸 · Pieter Maris🇺🇸 · James P. Vary🇺🇸

   We study charmonium and bottomonium as relativistic bound states in a light-front quantized Hamiltonian formalism. The effective Hamiltonian is based on light-front holography. We use a recently proposed longitudinal confinement to complete the soft-wall holographic potential for the heavy flavors. The spin structure is generated from the one-gluon exchange interaction with a running coupling. The adoption of asymptotic freedom improves the spectroscopy compared with previous light-front results. Within this model, we compute the mass spectroscopy, decay constants and the r.m.s. radii. We also present a detailed study of the obtained light-front wave functions and use the wave functions to compute the light-cone distributions, specifically the distribution amplitudes and parton distribution functions. Overall, our model provides a reasonable description of the heavy quarkonia.

   hep-phnucl-thPRD(2017)·149 citations
6. 06*

   The discrete charm of flavour and CP violation

   G. C. Branco🇵🇹 · M. N. Rebelo🇵🇹

   We point out that in the Standard Model (SM) there is no explanation why $|V_{23}{|}^2+|V_{13}{|}^2$ is of order $10^{-3}$. A framework is described for explaining this small mixing, involving the introduction of vector-like quarks. A symmetry is introduced so that at a first stage $V_{CKM}=1\mathrm{I}$ and only the third generation of quarks acquires a mass. It is shown that when interactions of vector-like quarks are taken into account a realistic quark mass spectrum is generated together with a correct $V_{CKM}$ matrix.

   hep-phJ.Phys.Conf.Ser.(2017)·2 citations
7. 07*

   High-precision calculation of the 4-loop contribution to the electron g-2 in QED

   Stefano Laporta🇮🇹

   I have evaluated up to 1100 digits of precision the contribution of the 891 4-loop Feynman diagrams contributing to the electron $g$-$2$ in QED. The total mass-independent 4-loop contribution is $a_e=-1.912245764926445574152647167439830054060873390658725345\dots {\left(\frac{\alpha }{\pi }\right)}^4$. I have fit a semi-analytical expression to the numerical value. The expression contains harmonic polylogarithms of argument $e^{\frac{i\pi }{3}}$, $e^{\frac{2i\pi }{3}}$, $e^{\frac{i\pi }{2}}$, one-dimensional integrals of products of complete elliptic integrals and six finite parts of master integrals, evaluated up to 4800 digits.

   hep-phPLB(2017)·228 citations
8. 08*

   Constraining compressed versions of MUED and MSSM using soft tracks at the LHC

   Sabyasachi Chakraborty🇮🇳 · Saurabh Niyogi🇮🇳 · K. Sridhar🇮🇳

   A compressed spectrum is an anticipated hideout for many beyond standard model scenarios. Such a spectrum naturally arises in the minimal universal extra dimension framework and also in supersymmetric scenarios. Low $p_T$ leptons and jets are characteristic features of such situations. Hence, a monojet with $/E_T$ has been the conventional signal at the Large Hadron Collider (LHC). However, we stress that inclusion of $p_T$-binned track observables from such soft objects provide very efficient discrimination of new physics signals against various SM backgrounds. We consider two benchmark points each for minimal universal extra dimension (MUED) and minimal supersymmetric standard model (MSSM) scenarios. We perform a detailed cut-based and multivariate analysis (MVA) to show that the new physics parameter space can be probed in the ongoing run of LHC at 13 TeV center-of-mass energy with an integrated luminosity $\sim$ 20-50 fb${}^{-1}$. When studied in conjunction with the dark matter relic density constraint assuming standard cosmology, we find that compressed MUED (with $\Lambda R=2$) can be already excluded from the existing data. Also, MVA turns out to be a better technique than regular cut-based analysis since tracks provide uncorrelated observables which would extract more information from an event.

   hep-phJHEP(2017)·10 citations
9. 09*

   Lindblad and Bloch equations for conversion of a neutron into an antineutron

   B.O. Kerbikov🇷🇺

   We propose a new approach based on the Lindblad and Bloch equations for the density matrix to the problem of a neutron into an antineutron conversion. We consider three strategies to search for conversion: experiments with trapped neutrons, oscillations in nuclei, and quasi-free propagation. We draw a distinction between $n\bar{n}$ oscillations in which the probability that a neutron transforms into an antineutron depends on time according to the sine-square law and the non-oscillatory overdamped $n\bar{n}$ conversion. We show that in all three cases decoherence due to the interaction with the environment leads to non-oscillatory evolution.

   hep-phNPA(2018)·21 citations
10. 10*

    Radiative corrections to false vacuum decay in quantum mechanics

    M.A. Bezuglov🇷🇺 · A.I. Onishchenko🇷🇺

    We consider radiative corrections to false vacuum decay within the framework of quantum mechanics for the general potential of the form 1/2 M q^2 (q-A)(q-B), where M , A and B are arbitrary parameters. For this type of potential we provide analytical results for Green function in the background of corresponding bounce solution together with one loop expression for false vacuum decay rate. Next, we discuss the computation of higher order corrections for false vacuum decay rate and provide numerical expressions for two and three loop contributions.

    hep-phhep-thquant-phPRD(2017)·5 citations
11. 11*

    Can we measure ${\theta }_{23}$ octant in 3+1 scheme?

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

    Current 3$\nu$ global fits predict two degenerate solutions for ${\theta }_{23}$: one lies in lower octant (${\theta }_{23}<\pi /4$), and the other belongs to higher octant (${\theta }_{23}>\pi /4$). Here, we study how the measurement of ${\theta }_{23}$ octant would be affected in the upcoming Deep Underground Neutrino Experiment (DUNE) if there exist a light eV-scale sterile neutrino. We show that in 3+1 scheme, a new interference term in ${\nu }_{\mu }\to {\nu }_e$ oscillation probability can spoil the chances of measuring ${\theta }_{23}$ octant completely.

    hep-phhep-exphysics.ins-detSpringer Proc.Phys.(2018)·0 citations
12. 12*

    Dynamical Origin of Seesaw

    Jiri Hosek🇨🇿

    In anomaly free gauged three-flavor SU(3)_f x SU(2)_L x U(1)_Y model of Yanagida with fermion and gauge boson masses described by conveniently chosen elementary scalar Higgs fields the neutrino mass matrix comes out in the seesaw form. Following Yanagida's suggestion we demonstrate that no Higgs fields are needed. Strong flavor gluon interactions themselves, treated in a separable approximation, result in universally split lepton and quark masses calculated in terms of a few parameters. While the realistic splitting of charged lepton and quark masses requires the electroweak and QCD radiative corrections the neutrino seesaw mass matrix comes out exact.

    hep-ph5 citations
13. 13*

    Scale of left-right symmetry

    Ravi Kuchimanchi🇺🇸

    Unlike the standard model where neutrino masses can be made arbitrarily small, we find in the minimal left-right symmetric model that Dirac type Yukawa coupling $h_D\sim 10^{-4.2}$ for ${\nu }_{\tau }$ is generated from charged fermion Yukawa couplings through one loop Renormalization Group (RG) running. Using the seesaw relation this implies that the natural scale for right-handed neutrino's Majorana mass (seesaw scale) $M_N=f{v}_R\gtrsim 2000TeV$. If we take the $SU(2{)}_R\times U(1{)}_{B-L}$ breaking scale $v_R$ to be below 50 TeV, so that it can be probed by LHC and a future collider, then the large $h_D$ generated on RG running increases the mass $m_{\nu }$ of the third generation light neutrino and severely suppresses the PMNS mixing angle ${\theta }_{23}$. We discuss the tuning needed for seesaw scales that can be probed by colliders and find the parameter space that can be tested by neutrino experiments for higher scales up to $10^{15}GeV$.

    hep-phhep-ex2 citations
14. 14*

    Polyakov loop correlator in perturbation theory

    Matthias Berwein🇩🇪 · Nora Brambilla🇩🇪 · Peter Petreczky🇺🇸 · Antonio Vairo🇩🇪

    We study the Polyakov loop correlator in the weak coupling expansion and show how the perturbative series re-exponentiates into singlet and adjoint contributions. We calculate the order $g^7$ correction to the Polyakov loop correlator in the short distance limit. We show how the singlet and adjoint free energies arising from the re-exponentiation formula of the Polyakov loop correlator are related to the gauge invariant singlet and octet free energies that can be defined in pNRQCD, namely we find that the two definitions agree at leading order in the multipole expansion, but differ at first order in the quark-antiquark distance.

    hep-phhep-lathep-thnucl-thPRD(2017)·22 citations
15. 15*

    Imprints of a light Sterile Neutrino at DUNE, T2HK and T2HKK

    Sandhya Choubey🇮🇳 · Debajyoti Dutta🇮🇳 · Dipyaman Pramanik🇮🇳

    We evaluate the impact of sterile neutrino oscillations in the so-called 3+1 scenario on the proposed long baseline experiment in USA and Japan. There are two proposals for the Japan experiment which are called T2HK and T2HKK. We show the impact of sterile neutrino oscillation parameters on the expected sensitivity of T2HK and T2HKK to mass hierarchy, CP violation and octant of ${\theta }_{23}$ and compare it against that expected in the case of standard oscillations. We add the expected ten years data from DUNE and present the combined expected sensitivity of T2HKK+DUNE to the oscillation parameters. We do a full marginalisation over the relevant parameter space and show the effect of the magnitude of the true sterile mixing angles on the physics reach of these experiments. We show that if one assumes that the source of CP violation is the standard CP phase alone in the test case, then it appears that the expected CP violation sensitivity decreases due to sterile neutrinos. However, if we give up this assumption, then the CP sensitivity could go in either direction. The impact on expected octant of ${\theta }_{23}$ and mass hierarchy sensitivity is shown to depend on the magnitude of the sterile mixing angles in a nontrivial way.

    hep-phPRD(2017)·58 citations
16. 16*

    Loops with heavy particles in multi Higgs production amplitudes

    M.B.Voloshin🇺🇸

    In view of a recently renewed interest to production of multiple Higgs bosons the amplitude for such process at the threshold of $n$ particles is considered. An explicit calculation is done for the loop corrections to the amplitude arising from interaction with a heavy fermion (e.g. top quark) and also with a heavy scalar. It is shown that such corrections generally break the scaling dependence on the number $n$ and the Higgs self coupling, which dependence is known from the past studies of models with one field. The correction due to the top quark loop is also found to be numerically large and exceeding that from the self coupling until very high $n$.

    hep-phPRD(2017)·10 citations
17. 17*

    Analysis of Deeply Virtual Compton Scattering Data at Jefferson Lab and Proton Tomography

    Raphaël Dupré🇫🇷 · Michel Guidal🇫🇷 · Silvia Niccolai🇫🇷 · Marc Vanderhaeghen🇩🇪

    The CLAS and Hall A collaborations at Jefferson Laboratory have recently released new results for the ep->ep{\gamma} reaction. We analyze these new data within the Generalized Parton Distribution formalism. Employing a fitter algorithm introduced and used in earlier works, we are able to extract from these data new constraints on the kinematical dependence of three Compton Form Factors. Based on experimental data, we subsequently extract the dependence of the proton charge radius on the quarks longitudinal momentum fraction.

    hep-phEPJA(2017)·53 citations
18. 18*

    Starobinsky-like Inflation, Supercosmology and Neutrino Masses in No-Scale Flipped SU(5)

    John Ellis🇬🇧 · Marcos A. G. Garcia🇺🇸 · Natsumi Nagata🇯🇵 · Dimitri V. Nanopoulos🇺🇸 · Keith A. Olive🇺🇸

    We embed a flipped $\mathrm{SU}(5)\times \mathrm{U}(1)$ GUT model in a no-scale supergravity framework, and discuss its predictions for cosmic microwave background observables, which are similar to those of the Starobinsky model of inflation. Measurements of the tilt in the spectrum of scalar perturbations in the cosmic microwave background, $n_s$, constrain significantly the model parameters. We also discuss the model's predictions for neutrino masses, and pay particular attention to the behaviours of scalar fields during and after inflation, reheating and the GUT phase transition. We argue in favor of strong reheating in order to avoid excessive entropy production which could dilute the generated baryon asymmetry.

    hep-phastro-ph.COgr-qchep-thJCAP(2017)·47 citations
19. 19*

    Spin partners of the $Z_b(10610)$ and $Z_b(10650)$ revisited

    V. Baru🇩🇪 · E. Epelbaum🇩🇪 · A. A. Filin🇩🇪 · C. Hanhart🇩🇪 · A. V. Nefediev🇷🇺

    We study the implications of the heavy-quark spin symmetry for the possible spin partners of the exotic states $Z_b(10610)$ and $Z_b(10650)$ in the spectrum of bottomonium. We formulate and solve numerically the coupled-channel equations for the $Z_b$ states that allow for a dynamical generation of these states as hadronic molecules. The force includes short-range contact terms and the one-pion exchange potential, both treated fully nonperturbatively. The strength of the potential at leading order is fixed completely by the pole positions of the $Z_b$ states such that the mass and the most prominent contributions to the width of the isovector heavy-quark spin partner states $W_{bJ}$ with the quantum numbers $J^{++}$ ($J=0,1,2$) come out as predictions. Since the accuracy of the present experimental data does not allow one to fix the pole positions of the $Z_b$'s reliably enough, we also study the pole trajectories of their spin partner states as functions of the $Z_b$ binding energies. It is shown that, once the heavy-quark spin symmetry is broken by means of the physical $B$ and $B^{\ast }$ masses, especially the pion tensor force has a significant impact on the location of the partner states clearly demonstrating the need of a coupled-channel treatment of pion dynamics to understand the spin multiplet pattern of hadronic molecules.

    hep-phhep-exnucl-thJHEP(2017)·52 citations
20. 20*

    Gauge-invariant approach to the beta function in Yang-Mills theories with universal extra dimensions

    M. Huerta-Leal🇲🇽 · H. Novales-Sánchez🇲🇽 · J. J. Toscano🇲🇽

    The radiative correction to beta function is comprehensively studied at 1 loop in the context of universal extra dimensions. Instead of using cutoffs to regularize 1-loop divergences, the dimensional regularization scheme is used. Large momenta effects are removed from physical amplitudes by adjusting the parameters of the appropriate counterterms. The use of a SU(N)-covariant gauge-fixing procedure is stressed. 1-loop contributions of KK excitations are characterized by discrete KK sums and continuous momenta sums, which can diverge. Two types of UVs are identified, one arising from poles of the gamma function and associated with short-distance effects in the usual 4-dimensional spacetime manifold, and the other emerging either from poles of the 1-dimensional Epstein function or from the gamma function, and corresponding to short-distance effects in the compact manifold. We address the cases of 5 and 4+n dimensions (n>1) separately. In 5 dimensions the 1-dimensional Epstein function is convergent, so the usual counterterm renormalizes the vacuum polarization function. For 4+n dimensions, the 1-dimensional Epstein function is divergent, so renormalization is implemented by interactions of canonical dimension higher than 4, already present in the effective theory. The polarization function is renormalized using both mass-dependent and mass-independent schemes, with extra-dimensions effects decoupling in the former case but not in the latter. The beta function is calculated for an arbitrary number of extra dimensions. Our main result is that Yang-Mills theory remains perturbative at 1 loop, which is in disagreement with the results obtained in the literature by using a cutoff regulator, which suggest that Yang-Mills theory in more than 4 dimensions ceases to be perturbative. We emphasize the advantages of a mass-dependent scheme in this type of theories, in which decoupling is manifest.

    hep-phPRD(2020)·4 citations
21. 21*

    Radial Scaling in Inclusive Jet Production at Hadron Colliders

    Frank E. Taylor🇺🇸

    Inclusive jet production in p-p and pbar-p collisions shows many of the same kinematic systematics as observed in single particle inclusive production at much lower energies. In an earlier study (1974) a phenomenology, called radial scaling, was developed for the single particle inclusive cross sections that attempted to capture the essential underlying physics of point-like parton scattering and the fragmentation of partons into hadrons suppressed by the kinematic boundary. The phenomenology was successful in emphasizing the underlying systematics of the inclusive particle productions. Here we demonstrate that inclusive jet production at the LHC in high-energy p-p collisions and at the Tevatron in pbar-p inelastic scattering show similar behavior. The ATLAS inclusive jet production plotted as a function of this scaling variable is studied for sqrt(s) of 2.76, 7 and 13 TeV and is compared to pbar-p inclusive jet production at 1.96 TeV measured at the CDF and D0 at the Tevatron and p-Pb inclusive jet production at the LHC ATLAS at sqrt(sNN) = 5.02 TeV. Inclusive single particle production at FNAL fixed target and ISR energies are compared to inclusive J/Psi production at the LHC measured in ATLAS, CMS and LHCb. Striking common features of the data are discussed.

    hep-phPRD(2018)·1 citation
22. 22*

    Impact of Rare Decays $t\to {\ell }^{\prime }\nu b\ell \ell$ and $t\to q{q}^{\prime }b\ell \ell$ on Searches for Top-Associated Physics

    Peter Onyisi🇺🇸 · Aaron Webb🇺🇸

    Searches for top quark-associated physics such as $t\bar{t}W$ or $t\bar{t}H$ in final states with multiple leptons require a careful accounting of expected backgrounds due to the lack of reconstructible resonances. We demonstrate that the rare top quark decays $t\to {\ell }^{\prime }\nu b\ell \ell$ and $t\to q{q}^{\prime }b\ell \ell$, when a soft lepton is not detected, can contribute a non-negligible background to such searches. Simulations in the LHC experiments typically do not account for such decays and as such backgrounds to such searches may be underestimated.

    hep-phhep-exJHEP(2018)·5 citations
23. 23*

    Lepton flavor non-universality in the B-sector: a global analyses of various new physics models

    Ashutosh Kumar Alok🇮🇳 · Jacky Kumar🇮🇳 · Dinesh Kumar🇮🇳 · Ruchi Sharma🇮🇳

    The measurements of the ratios $R_{K^{(\ast )}}$ along with $R_{D^{(\ast )}}$ hint towards lepton flavor non universality which is in disagreement with the standard model. In this work, we reanalyze the four new physics models, which are widely studied in the literature as a candidates for the simultaneous explanations of these measurements. These are, standard model like vector boson (VB), $SU(2{)}_L$-singlet vector leptoquark ($U_1$), $SU(2{)}_L$-triplet scalar leptoquark ($S_3$) and $SU(2{)}_L$ triplet vector leptoquark ($U_3$) models. We assume a coupling only to the third generation in the weak basis, so that the $b\to s{\mu }^{+}{\mu }^{-}$ transition is generated only via mixing effects. Preforming a global fit to all relevant data, we show that the vector boson model violates the current upper bound on $Br(\tau \to 3\mu )$ and hence is inconsistent with the present data. Further, we show that within this framework, the $U_1$ leptoquark model cannot simultaneously accommodate $R_{K^{(\ast )}}$ and $R_{D^{(\ast )}}$ measurements. We emphasize that this conclusion is independent of the additional constraints coming from renormaliztion group running effects and high-$p_T$ searches. In addition, we show that the $S_3$ and $U_3$ models are highly disfavored by the constraints coming from $b\to s\nu \bar{\nu }$ data. Finally, we find a that hypothesis of two LQ particles is also challenged by $b\to s\bar{\nu }\nu$ data.

    hep-phhep-exEPJC(2019)·65 citations
24. 24*

    Exceptional Composite Dark Matter

    Guillermo Ballesteros🇫🇷 · Adrian Carmona🇨🇭 · Mikael Chala🇪🇸

    We study the dark matter phenomenology of non-minimal composite Higgs models with $SO(7)$ broken to the exceptional group $G_2$. In addition to the Higgs, three pseudo-Nambu-Goldstone bosons arise, one of which is electrically neutral. A parity symmetry is enough to ensure this resonance is stable. In fact, if the breaking of the Goldstone symmetry is driven by the fermion sector, this ${\mathbb{Z}}_2$ symmetry is automatically unbroken in the electroweak phase. In this case, the relic density, as well as the expected indirect, direct and collider signals are then uniquely determined by the value of the compositeness scale, $f$. Current experimental bounds allow to account for a large fraction of the dark matter of the Universe if the dark matter particle is part of an electroweak triplet. The totality of the relic abundance can be accommodated if instead this particle is a composite singlet. In both cases, the scale $f$ and the dark matter mass are of the order of a few TeV.

    hep-phastro-ph.COEPJC(2017)·46 citations
25. 25*

    Study of a background reconstruction method for the measurement of D-meson azimuthal angular correlations

    Long Ma🇨🇳 · Xin Dong🇺🇸 · Huan-Zhong Huang🇺🇸 · Yu-Gang Ma🇨🇳

    We study experimental background reconstruction methods for the measurement of $D-\overline{D}$ correlation using a PYTHIA simulation. Like-sign and side-band background methods that are widely used in the experimental measurements of single $D$-meson production yields were deployed for the correlation background study. It is found that the like-sign method which well describes the combinatorial background of single $D^0$ meson yields fails to reproduce the correlated background in the $D^0-\overline{D^0}$ correlation measurement, while the side-band background method yields a good description of the background for both the single $D^0$ yields and of the correlated background of the $D^0-\overline{D^0}$ correlation measurement.

    hep-phnucl-thNucl.Sci.Tech.(2021)·6 citations
26. 26*

    Connected and Disconnected Contractions in Pion-Pion Scattering

    Neramballi Ripunjay Acharya🇨🇳 · Feng-Kun Guo🇨🇳 · Ulf-G. Meißner🇩🇪 · Chien-Yeah Seng🇨🇳

    We show that the interplay of chiral effective field theory and lattice QCD can be used in the evaluation of so-called disconnected diagrams, which appear in the study of the isoscalar and isovector channels of pion-pion scattering and have long been a major challenge for the lattice community. By means of partially-quenched chiral perturbation theory, we distinguish and analyze the effects from different types of contraction diagrams to the pion-pion scattering amplitude, including its scattering lengths and the energy-dependence of its imaginary part. Our results may be used to test the current degree of accuracy of lattice calculation in the handling of disconnected diagrams, as well as to set criteria for the future improvement of relevant lattice computational techniques that may play a critical role in the study of other interesting QCD matrix elements.

    ↳ hep-lathep-phnucl-thNPB(2017)·15 citations
27. 27*

    Dark Energy Induced Anisotropy in Cosmic Expansion

    Chien-Ting Chen · Pisin Chen

    In order to understand the nature of the accelerating expansion of the late-time universe, it is important to experimentally determine whether dark energy is a cosmological constant or dynamical in nature. If dark energy already exists prior to inflation, which is a reasonable assumption, then one expects that a dynamical dark energy would leave some footprint in the anisotropy of the late-time accelerated expansion. To demonstrate the viability of this notion, we invoke the quintessence field with the exponential potential as one of the simplest dynamical dark energy models allowed by observations. We investigate the effects of its quantum fluctuations (the physical origin of the perturbation being isocurvature) generated during inflation and having fully positive correlation with the primordial curvature perturbations, and estimate the anisotropy of the cosmic expansion so induced. We show that the primordial amplitude of quantum fluctuations of quintessence field {\delta\phi}_P can be related to the tensor-to-scalar ratio r, and we calculate the perturbed luminosity distance to first order and the associated luminosity distance power spectrum, which is an estimator of anisotropicity of late-time accelerated expansion. We find that the gravitational potential at large scales and late times is less decayed in QCDM compared to that in {\Lambda}CDM so that the smaller the redshift and multipole, the more relative deficit of power in QCDM. Our results of luminosity distance power spectrum also show the similar conclusions of suppression as that of the previous investigation regarding the effect of quantum fluctuations of quintessence field on the CMB temperature anisotropies.

    ↳ astro-ph.COhep-phEPJC(2019)·2 citations
28. 28*

    Charge redistribution from novel magneto-vorticity coupling in anomalous hydrodynamics

    Koichi Hattori🇨🇳 · Yi Yin🇺🇸

    We discuss new transport phenomena in the presence of both a strong magnetic field and a vortex field. Their interplay induces a charge distribution and a current along the magnetic field. We show that the associated transport coefficients can be obtained from a simple analysis of the single-particle distribution functions and also from the Kubo formula calculation. The consistent results from these analyses suggest that the transport coefficients are tied to the chiral anomaly in the (1+1) dimension because of the dimensional reduction in the lowest Landau levels.

    ↳ nucl-thhep-phnucl-exNPA(2017)·0 citations
29. 29*

    Testing fundamental interactions on the helium atom

    Krzysztof Pachucki🇵🇱 · Vojtěch Patkóš🇨🇿 · Vladimir Yerokhin🇷🇺

    We critically examine the current status of theoretical calculations of the energies, the fine structure, and the isotope shift of the lowest-lying states of helium, searching for unresolved discrepancies with experiments. Calculations are performed within the quantum electrodynamics expansion in powers of the fine structure constant $\alpha$ and the electron-to-nucleus mass ratio $m/M$. For energies, theoretical results are complete through orders ${\alpha }^{6}m$ and ${\alpha }^6{m}^2/M$, with the resulting accuracy ranging from $0.5$ to $2$~MHz for the $n=2$ states. The fine-structure splitting of the $2^{3}P$ state is predicted with a much better accuracy, 1.7~kHz, as a consequence of a calculation of the next-order ${\alpha }^{7}m$ effect. An excellent agreement of the theoretical predictions with the recent measurements of the fine structure provides one of the best tests of the bound-state QED in few-electron systems and determines the fine-structure constant $\alpha$ with an accuracy of 31~ppb. The isotope shift between ${}^3$He and ${}^4$He is treated theoretically with a sub-kHz accuracy, which allows for a high-precision determination of the differences of the nuclear charge radii $\delta r^2$. Several such determinations, however, yield results that are in a 4$\sigma$ disagreement with each other, what remains unexplained. Apart from this, we find no significant discrepancies between theory and experiment for the helium atom. In the future, a calculation of the next-order ${\alpha }^{7}m$ effect for energy levels will enable determinations of the nuclear charge radii from atomic transition frequencies with an accuracy better than 1\%. Combined with the complementary determinations from muonic atoms, this will provide a sensitive test of universality in electromagnetic interactions of leptons and contribute to the solution of the proton charge radius puzzle.

    ↳ physics.atom-phhep-phPRA(2017)·72 citations
30. 30*

    Anomalous Transport Properties of Dense QCD in a Magnetic Field

    Vivian de la Incera🇺🇸

    Despite recent advancements in the study and understanding of the phase diagram of strongly interacting matter, the region of high baryonic densities and low temperatures has remained difficult to reach in the lab. Things are expected to change with the planned HIC experiments at FAIR in Germany and NICA in Russia, which will open a window to the high-density-low-temperature segment of the QCD phase map, providing a unique opportunity to test the validity of model calculations that have predicted the formation of spatially inhomogeneous phases with broken chiral symmetry at intermediate-to-high densities. Such a density region is also especially relevant for the physics of neutron stars, as they have cores that can have several times the nuclear saturation density. On the other hand, strong magnetic fields, whose presence is fairly common in HIC and in neutron stars, can affect the properties of these exotic phases and lead to signatures potentially observable in these two settings. In this paper, I examine the anomalous transport properties produced by the spectral asymmetry of the lowest Landau level (LLL) in a QCD-inspired NJL model with a background magnetic field that exhibits chiral symmetry breaking at high density via the formation of a Dual Chiral Density Wave (DCDW) condensate. It turns out that in this model the electromagnetic interactions are described by the axion electrodynamics equations and there is a dissipationless Hall current.

    ↳ nucl-thcond-mat.mtrl-scicond-mat.str-elhep-phJ.Phys.Conf.Ser.(2017)·1 citation
31. 31*

    Low-energy $\eta$-nucleon interaction studied with $\eta$ photoproduction off the deuteron

    S. X. Nakamura (1, 2)🇯🇵 · H. Kamano (3,4)🇯🇵 · T. Ishikawa (5,6) ((1) Osaka Univ., (2) Univ. Cruzeiro do Sul, (3) KEK, (4) J-PARC, (5) ELPH, (6) Tohoku Univ.)🇯🇵

    We develop a reaction model for $\eta$ photoproduction off the deuteron ($\gamma d\to \eta pn$), and study the reaction at a special kinematics, where the photon beam energy is $\sim 0.94$ GeV and the scattered proton is detected at $\sim 0^{\circ }$, for the purpose of determining the $\eta$-nucleon scattering length ($a_{\eta N}$) and effective range ($r_{\eta N}$). In this kinematics, the $\eta$-nucleon elastic rescattering is significantly enhanced while other background mechanisms being suppressed. We show that a ratio $R$, the $\gamma d\to \eta pn$ cross section divided by the $\gamma p\to \eta p$ cross section convoluted with the proton momentum distribution in the deuteron, has a very good resolving power of $a_{\eta N}$ and $r_{\eta N}$. We conclude that the $R$ data with 5% error, binned in 1 MeV width of the $\eta$-neutron invariant mass, can determine $\mathrm{Re}[a_{\eta N}]$ ($\mathrm{Re}[r_{\eta N}]$) at the precision of $\sim \pm$0.1 fm ($\sim \pm$0.5 fm), significantly narrowing down the previously estimated ranges of the parameters. To arrive at the conclusion, it is essential to use the $\gamma d\to \eta pn$ reaction model equipped with elementary amplitudes that are well constrained by $\pi N$ and $\gamma N$ reaction data through a sophisticated coupled-channels analysis. This result strongly motivates the Research Center for Electron Photon Science (ELPH) at Tohoku University to measure $R$.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2017)·16 citations
32. 32*

    Taming the Signal-to-Noise Problem in Lattice QCD by Phase Reweighting

    Michael L. Wagman🇺🇸 · Martin J. Savage🇺🇸

    Path integrals describing quantum many-body systems can be calculated with Monte Carlo sampling techniques, but average quantities are often subject to signal-to-noise ratios that degrade exponentially with time. A phase-reweighting technique inspired by recent observations of random walk statistics in correlation functions is proposed that allows energy levels to be extracted from late-time correlation functions with time-independent signal-to-noise ratios. Phase reweighting effectively includes dynamical refinement of source magnitudes but introduces a bias associated with the phase. This bias can be removed by performing an extrapolation, but at the expense of re-introducing a signal-to-noise problem. Lattice Quantum Chromodynamics calculations of the $\rho$ and nucleon masses and of the $\Xi \Xi$ binding energy show consistency between standard results obtained using earlier-time correlation functions and phase-reweighted results using late-time correlation functions inaccessible to standard statistical analysis methods.

    ↳ hep-latcond-mat.stat-mechcond-mat.str-elhep-ph+120 citations
33. 33*

    From Linear to Non-linear SUSY and Back Again

    N. Cribiori🇮🇹 · G. Dall'Agata🇮🇹 · F. Farakos🇮🇹

    We show that couplings of the goldstino field, appearing when global supersymmetry is broken, can always be described in superspace by means of a nilpotent chiral superfield $X$, satisfying $X^2=0$. This applies to both F-term and D-term supersymmetry breaking, even when the supersymmetry breaking model admits a linear description.

    ↳ hep-thhep-phJHEP(2017)·34 citations
34. 34*

    Signatures of extra dimensions in gravitational waves

    David Andriot🇩🇪 · Gustavo Lucena Gómez🇩🇪

    Considering gravitational waves propagating on the most general 4+N-dimensional space-time, we investigate the effects due to the N extra dimensions on the four-dimensional waves. All wave equations are derived in general and discussed. On Minkowski4 times an arbitrary Ricci-flat compact manifold, we find: a massless wave with an additional polarization, the breathing mode, and extra waves with high frequencies fixed by Kaluza-Klein masses. We discuss whether these two effects could be observed.

    ↳ hep-thastro-ph.COastro-ph.HEgr-qc+1JCAP(2017)·80 citations
35. 35*

    Relativistic Dynamics of the Compton Diffusion on a Bound Electron

    Salwa Alsaleh🇸🇦

    A covariant relativistic formalism for the electron-photon and nuclear dynamics is summarised making more accurate predictions in agreement with experiments for Compton scattering in shells with large electron binding energy. An exact solution for the Dirac equation for an electron in the nuclear Coulomb field is obtained, in order to write the relativistic dynamics for this QED process. This is a preparation for the calculation of the relativistic cross-section for Compton scattering on bound electrons; as a precision test for QED.

    ↳ physics.hist-phhep-phEur.Phys.J.Plus(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.