Wed·May 17, 2017Wednesday·May 17, 2017

1. 01*

   Gauge invariant one-loop corrections to Higgs boson couplings in non-minimal Higgs models

   Shinya Kanemura🇯🇵 · Mariko Kikuchi🇹🇼 · Kodai Sakurai🇯🇵 · Kei Yagyu🇮🇹

   We comprehensively evaluate renormalized Higgs boson couplings at one-loop level in non-minimal Higgs models such as the Higgs Singlet Model (HSM) and the four types of Two Higgs Doublet Models (THDMs) with a softly-broken $Z_2$ symmetry. The renormalization calculation is performed in the on-shell scheme improved by using the pinch technique to eliminate the gauge dependence in the renormalized couplings. We first review the pinch technique for scalar boson two-point functions in the Standard Model (SM), the HSM and the THDMs. We then discuss the difference in the results of the renormalized Higgs boson couplings between the improved on-shell scheme and the ordinal one with a gauge dependence appearing in mixing parameters of scalar bosons. Finally, we widely investigate how we can identify the HSM and the THDMs focusing on the pattern of deviations in the renormalized Higgs boson couplings from predictions in the SM.

   hep-phPRD(2017)·86 citations
2. 02*

   Surveying the SO(10) Model Landscape: The Left-Right Symmetric Case

   Frank F. Deppisch🇬🇧 · Tomas E. Gonzalo🇳🇴 · Lukas Graf🇬🇧

   Grand Unified Theories (GUTs) are a very well motivated extensions of the Standard Model (SM), but the landscape of models and possibilities is overwhelming, and different patterns can lead to rather distinct phenomenologies. In this work we present a way to automatise the model building process, by considering a top to bottom approach that constructs viable and sensible theories from a small and controllable set of inputs at the high scale. By providing a GUT scale symmetry group and the field content, possible symmetry breaking paths are generated and checked for consistency, ensuring anomaly cancellation, SM embedding and gauge coupling unification. We emphasise the usefulness of this approach for the particular case of a non-supersymmetric SO(10) model with an intermediate left-right symmetry and we analyse how low-energy observables such as proton decay and lepton flavour violation might affect the generated model landscape.

   hep-phPRD(2017)·23 citations
3. 03*

   Probing the Anomalous FCNC tqgamma Couplings at Large Hadron electron Collider

   I. Turk Cakir (Giresun Univ.)🇹🇷 · A. Yilmaz (Giresun Univ.)🇹🇷 · H. Denizli (Abant Izzet Baysal Univ.)🇹🇷 · A. Senol (Abant Izzet Baysal Univ.)🇹🇷 · H. Karadeniz (Giresun Univ.)🇹🇷 · O. Cakir (Ankara Univ.)🇹🇷

   We investigate the anomalous flavour changing neutral current (FCNC) interactions of top quark through the process $e^{-}p\to e^{-}{W}^{\pm }q+X$. We calculate the signal and background cross sections in electron proton collisions at Large Hadron electron Collider (LHeC) with a 7 TeV proton beam from the LHC and a new 60 GeV electron beam from energy recovery linac (ERL). We study the relevant background processes including one electron and three jets in the final state. The distributions of the invariant mass of two jets and an additional jet tagged as $b$-jet are used to account signal and background events after the analysis cuts. We find upper bounds on anomalous FCNC couplings $\lambda$ of the order of $10^{-2}$ at LHeC for a luminosity projection of $100$ fb${}^{-1}$ together with the fast simulation of detector effects. As a matter of interest, we analyze the sensitivity to the couplings $({\lambda }_u,{\lambda }_c)$ and find an enhanced sensitivity to ${\lambda }_c$ at the LHeC when compared to the results from the HERA.

   hep-phAdv.High Energy Phys.(2017)·23 citations
4. 04*

   Natural Fermion Hierarchies from Random Yukawa Couplings

   Gero von Gersdorff🇧🇷

   The Standard Model of particle physics requires Yukawa matrices with eigenval- ues that differ by orders of magnitude. We propose a novel way to explain this fact without any small or large parameters. The mechanism is based on the observation that products of matrices of random order one-numbers have hierarchical spectra. The same mechanism can easily account for the hierarchical structure of the quark mixing matrix.

   hep-phJHEP(2017)·27 citations
5. 05*

   Correlations of ${ϵ}_K^{\prime }/{ϵ}_K$ with $K\to \pi \nu \overline{\nu }$ in Models of New Physics

   Teppei Kitahara🇩🇪

   Recent calculations have pointed to a 2.8 $\sigma$ tension between data on ${ϵ}_K^{\prime }/{ϵ}_K$ and the standard-model (SM) prediction. Several new physics (NP) models can explain this discrepancy, and such NP models are likely to predict deviations of $\mathcal{B}(K\to \pi \nu \overline{\nu })$ from the SM predictions, which can be probed precisely in the near future by NA62 and KOTO experiments. We present correlations between ${ϵ}_K^{\prime }/{ϵ}_K$ and $\mathcal{B}(K\to \pi \nu \overline{\nu })$ in two types of NP scenarios: a box dominated scenario and a $Z$-penguin dominated one. It is shown that different correlations are predicted and the future precision measurements of $K\to \pi \nu \overline{\nu }$ can distinguish both scenarios.

   hep-phhep-ex1 citation
6. 06*

   Radiative decays of a singlet scalar boson through vector-like quarks

   Yeo Woong Yoon🇰🇷 · Kingman Cheung🇹🇼 · Sin Kyu Kang🇰🇷 · Jeonghyeon Song🇰🇷

   If the standard model Higgs boson were much heavier, it would appear as a broad resonance since its decay into a pair of longitudinally polarized gauge bosons is highly enhanced. We study whether the same enhancement happens at loop level in a simple extension of the standard model with a singlet scalar boson $S$. In order to focus on the loop effects, we assume that $S$ does not interact with the standard model particles at tree level. The singlet scalar $S$ is linked to the standard model world by vector-like quarks running in the loop. We introduce three vector-like quark multiplets, an $SU(2{)}_L$ doublet, an up-type singlet, and a down-type singlet. There are two kinds of loop effects in the $S$ phenomenology, the mixing with the Higgs boson and the radiative decays into $hh$, $WW$, $ZZ$, $gg$, and $\gamma \gamma$ through the triangle loops. We show that the crucial condition for enhancing loop effects including the longitudinal polarization enhancement is the large mass differences among vector-like quarks. The current LHC constraints on $S$ from the heavy scalar searches and the Higgs precision data are shown to be very significant: the mixing angle with the Higgs boson should be smaller than about 0.1 for $m_S=750$ GeV.

   hep-phPRD(2017)·4 citations
7. 07*

   Kira - A Feynman Integral Reduction Program

   Philipp Maierhoefer🇩🇪 · Johann Usovitsch🇩🇪 · Peter Uwer🇩🇪

   In this article, we present a new implementation of the Laporta algorithm to reduce scalar multi-loop integrals---appearing in quantum field theoretic calculations---to a set of master integrals. We extend existing approaches by using an additional algorithm based on modular arithmetic to remove linearly dependent equations from the system of equations arising from integration-by-parts and Lorentz identities. Furthermore, the algebraic manipulations required in the back substitution are optimized. We describe in detail the implementation as well as the usage of the program. In addition, we show benchmarks for concrete examples and compare the performance to Reduze 2 and FIRE 5. In our benchmarks we find that Kira is highly competitive with these existing tools.

   hep-phComput.Phys.Commun.(2018)·553 citations
8. 08*

   Flavor Non-universality Gauge Interactions and Anomalies in B-Meson Decays

   Yong Tang🇯🇵 · Yue-Liang Wu🇨🇳

   Motivated by flavor non-universality and anomalies in semi-leptonic B-meson decays, we present a general and systematic discussion about how to construct anomaly-free $U(1{)}^{\prime }$ gauge theories based on an extended standard model with only three right-handed neutrinos. If all standard model fermions are vector-like under this new gauge symmetry, the most general family non-universal charge assignments, $(a,b,c)$ for three-generation quarks and $(d,e,f)$ for leptons, need satisfy just one condition to be anomaly-free, $3(a+b+c)=-(d+e+f)$. Any assignment can be linear combinations of five independent anomaly-free solutions. We also illustrate how such models can generally lead to flavor-changing interactions and easily resolve the anomalies in B-meson decays. Probes with $B_s-{\bar{B}}_s$ mixing, decay into ${\tau }^{\pm }$, dilepton and dijet searches at colliders are also discussed.

   hep-phhep-exCPC(2018)·59 citations
9. 09*

   EWPD in the SMEFT and the $\mathcal{O}(y_t^2,\lambda )$ one loop $Z$ decay width

   Michael Trott🇩🇰

   The interpretation of electroweak precision data in the Standard Model Effective Field Theory is discussed. One loop corrections $\propto y_t^2,\lambda$ to the partial $Z$ decay widths and ratios of partial widths in this theory are discussed. A reparameterization invariance and the non-minimal character of matching onto this theory is reviewed.

   hep-ph4 citations
10. 10*

    Massless quark production in chromoelectric field with back reaction

    M. R. Jia🇨🇳 · F. Wan🇨🇳 · C. Lv🇨🇳 · B. S. Xie🇨🇳

    We study the massless quark production in $SU(2)$ gauge chromoelectric field by single-time Wigner function covariantly with back reaction. The evolution of field and current are investigated. For a phenomenological distribution function, both the time and momentum dependence have been studied. Interesting phenomena are found, which are: when considering the back reaction, the yield of quark production is higher than the Bjorken expanding field, and momentum 'gap' with confinement phenomenon exists in the phenomenological distribution function. To have a better understanding on the phenomena, components of the Wigner function are qualitatively analyzed.

    hep-phCommun.Theor.Phys.(2018)·0 citations
11. 11*

    $B$ decays to radially excited $D$ mesons in Heavy Quark Effective Theory

    Damir Bečirević🇫🇷 · Alain Le Yaouanc🇫🇷 · Luis Oliver🇫🇷

    Semileptonic transitions $\overline{B}\to D^{(n)}\ell \overline{\nu }$, where $D^{(n)}(n\ne 0)$ is a radially excited meson, have recently attracted much attention as a way to understand some puzzles between theory and data. Following closely the formalism of Falk and Neubert for the elastic case, we study the $1/m_Q$ corrections to the heavy quark limit, in which the inelastic Isgur-Wise function vanishes at zero recoil, ${\xi }^{(n)}(1)=0(n\ne 0)$. We find simple formulas that involve the derivative ${\xi }^{(n{)}^{\prime }}(1)$, and we propose a number of ways of isolating this quantity in practice. We formulate also a generalization to the inelastic case of Luke's theorem. On the other hand, although some $1/m_Q$ HQET results are satisfied in the Bakamjian-Thomas relativistic quark model, we emphasize the problems concerning these corrections in this scheme.

    hep-phhep-exhep-latPRD(2017)·2 citations
12. 12*

    Unexpected pattern of transitions to radial excitations by heavy quark current

    Damir Bečirević🇫🇷 · Alain Le Yaouanc🇫🇷 · Luis Oliver🇫🇷 · Jean-Claude Raynal🇫🇷

    Motivated by the claimed possibility of a large contribution of the first radial excitation of the $D^{(\ast )}$ to the $B$ semileptonic decay into charmed mesons, also invoked to solve the "$1/2$ vs. $3/2$ semileptonic puzzle", we discuss the transitions to heavy-light radial excitations by a heavy $b\to c$ quark current. We first consider a HQET sum rule, which provides a bound on the slopes of Isgur-Wise functions which we then calculate in the Bakamjian-Thomas framework which both guaranties covariance in the heavy quark limit and satisfies a set of HQET sum rules. We observe a remarkable property that for a large variety of wave functions the transition to the first radial excitation is very small while the transition matrix element to the second radial excitation is large and dominant in saturating the HQET sum rule. This is opposite to what is found in non-relativistic models, where the transition to the first radial excitation dominates the sum rule. The relative magnitude of the transition to the second excitation appears to be weakly dependent on the dynamical scale (radius of the bound states), and the same holds true for the slope of the elastic transition. These features could be tested in the heavy mass limit of lattice QCD. This pattern is shown to be related to the general structure of the Bakamjian-Thomas model, it is independent of the spin structure of the approach and derives mainly from the Lorentz transformation of the spatial wave function, a feature often disregarded in quark models.

    hep-phhep-latPRD(2017)·4 citations
13. 13*

    The anomalous decay $f_1(1285)\to \rho \gamma$ and related processes

    A. A. Osipov🇷🇺 · A. A. Pivovarov🇷🇺 · M. K. Volkov🇷🇺

    We work out the low-energy expansion of the anomalous $f_1(1285)\to \rho \gamma$ decay amplitude by using the Nambu--Jona-Lasinio model with $U(2)\times U(2)$ chiral symmetric four-quark interactions in the one-quark-loop approximation. The related processes $f_1(1285)\to \omega \gamma$, $a_1(1260)\to \omega \gamma$, and $a_1(1260)\to \rho \gamma$, are also considered. An effective meson Lagrangian responsible for $f_1\rho \gamma$, $f_1\omega \gamma$, $a_1\rho \gamma$ and $a_1\omega \gamma$ interactions is found. The predicted radiative decay widths, ${\Gamma }_{f_1\to {\rho }^0\gamma }=311\text{mbox}keV$, ${\Gamma }_{f_1\to \omega \gamma }=34.3\text{mbox}keV$, ${\Gamma }_{a_1\to {\rho }^0\gamma }=26.8\text{mbox}keV$, ${\Gamma }_{a_1\to \omega \gamma }=238\text{mbox}keV$, allow an experimental test of the hypothesis that $f_1(1285)$ and $a_1(1260)$-mesons have a quark-antiquark nature. At present, only the $f_1(1285)\to \rho \gamma$ decay has been measured. Our result is in remarkably good agreement with the recent data of CLAS Collaboration ${\Gamma }_{f_1\to {\rho }^0\gamma }=453\pm 177\text{mbox}keV$, but disagrees with the PDG-based estimate of ${\Gamma }_{f_1\to {\rho }^0\gamma }=1326\pm 313\text{mbox}keV$. The calculations presented require a minimum of theoretical input, and are shown to be consistent with the non-renormalization theorems of QCD.

    hep-phPRD(2017)·22 citations
14. 14*

    Neutrino mass matrices with one texture equality and one vanishing neutrino mass

    Jinzhong Han🇨🇳 · Ruihong Wang🇨🇳 · Weijian Wang🇨🇳 · Xing-Ning Wei🇨🇳

    In the light of latest data of neutrino oscillation experiments, we carry out a systematic investigation on the texture structures of Majorana neutrino mass matrix $M_{\nu }$, which contain one vanishing neutrino mass and an equality between two matrix elements. Among 15 logically possible patterns, it is found that for norm order ($m_3>m_2>m_1=0$) of neutrino masses only five of them are compatible with recent experimental data at the $3\sigma$ level, while for inverted order ($m_2>m_1>m_3=0$) ten patterns is phenomenologically allowed. In the numerical analysis, we perform a scan over the parameter space of all viable patterns to get a large sample of scattering points. We present the implications of each allowed pattern for three mixing angles $({\theta }_{12},{\theta }_2,{\theta }_3)$, leptonic CP violation and neutrinoless double-beta decay, predicting strong correlations between oscillation parameters. The theoretical realization of a concrete example is discussed in the framework of Froggatt-Nielsen mechanism.

    hep-phPRD(2017)·16 citations
15. 15*

    Impact of CP-violating interference effects on MSSM Higgs searches

    Elina Fuchs🇮🇱 · Georg Weiglein🇩🇪

    Interference and mixing effects between neutral Higgs bosons in the MSSM with complex parameters are shown to have a significant impact on the interpretation of LHC searches for additional Higgs bosons. Complex MSSM parameters introduce mixing between the CP-even and CP-odd Higgs states and generate CP-violating interference terms. Both effects are enhanced in the case of almost degenerate states. Employing as an example an extension of a frequently used benchmark scenario by a non-zero phase ${\varphi }_{A_t}$, the interference contributions are obtained for the production of neutral Higgs bosons in gluon-fusion and in association with b-quarks followed by the decay into a pair of $\tau$-leptons. While the resonant mixing increases the individual cross sections for the two heavy Higgs bosons $h_2$ and $h_3$, strongly destructive interference effects between the contributions involving $h_2$ and $h_3$ leave a considerable parameter region unexcluded that would appear to be ruled out if the interference effects were neglected.

    hep-phhep-exEPJC(2018)·29 citations
16. 16*

    Constrains of Charge-to-Mass Ratios on Noncommutative Phase Space

    Kai Ma🇨🇳

    Based on recent measurements on the charge-to-mass ratios of proton and anti-proton, we study constraints on the parameters of noncommutative phase space. We find that while the limit on the parameter of coordinate noncommutativity is weak, it is very strong on the parameter of momentum noncommutativity, $\sqrt{\xi }\lesssim 1\mu \mathrm{eV}$. Therefore, the charge-to-mass ratio experiment has a strong sensitivity on the momentum noncommutativity, and enhancement of future experimental achievement can further pin down the momentum noncommutativity.

    hep-phquant-phAdv.High Energy Phys.(2017)·13 citations
17. 17*

    New method of computing the contributions of graphs without lepton loops to the electron anomalous magnetic moment in QED

    Sergey Volkov🇷🇺

    This paper presents a new method of numerical computation of the QED contributions to the electron anomalous magnetic moment which arises from Feynman graphs containing electron and photon lines and not containing electron loops. The method consists of two parts. The first part is the forest-like subtraction formula that removes all ultraviolet and infrared divergences in each Feynman graph point-by-point in Feynman-parametric space. The second part is the importance sampling Monte-Carlo algorithm with the probability density function that is constructed for each Feynman graph individually. The method is fully automated at any order of the perturbation series. The results of applying the method to 2-loop, 3-loop, 4-loop Feynman graphs and to some individual 5-loop graphs are presented.

    hep-phPRD(2017)·30 citations
18. 18*

    Deuteron transverse densities in holographic QCD

    Chandan Mondal🇨🇳 · Dipankar Chakrabarti🇮🇳 · Xingbo Zhao🇨🇳

    We investigate the transverse charge density in the longitudinally as well as transversely polarized deuteron using the recent empirical description of the deuteron electromagnetic form factors in the framework of holographic QCD. The predictions of the holographic QCD are compared with the results of a standard phenomenological parameterization. In addition, we evaluate GPDs and the gravitational form factors for the deuteron. The longitudinal momentum densities are also investigated in the transverse plane.

    hep-phEPJA(2017)·18 citations
19. 19*

    A Study of Invisible Neutrino Decay at DUNE and its Effects on ${\theta }_{23}$ Measurement

    Sandhya Choubey🇮🇳 · Srubabati Goswami🇮🇳 · Dipyaman Pramanik🇮🇳

    We study the consequences of invisible decay of neutrinos in the context of the DUNE experiment. We assume that the third mass eigenstate is unstable and decays to a light sterile neutrino and a scalar or a pseudo-scalar. We consider DUNE running in 5 years neutrino and 5 years antineutrino mode and a detector volume of 40 kt. We obtain the bounds on the rest frame life time ${\tau }_3$ normalized to the mass $m_3$ as ${\tau }_3/m_3>4.50\times 10^{-11}$ s/eV at 90\% C.L. for a normal hierarchical mass spectrum. We also find that DUNE can discover neutrino decay for ${\tau }_3/m_3>4.27\times 10^{-11}$ s/eV at 90\% C.L. In addition, for an unstable ${\nu }_3$ with an illustrative value of ${\tau }_3/m_3$ = $1.2\times 10^{-11}$ s/eV, the no decay case gets disfavoured at the $3\sigma$ C.L. At 90\% C.L. the allowed range for this true value is obtained as $1.71\times 10^{-11}>{\tau }_3/m_3>9.29\times 10^{-12}$ in units of s/eV. We also study the correlation between a non-zero ${\tau }_3/m_3$ and standard oscillation parameters and find an interesting correlation in the appearance channel probability with the mixing angle ${\theta }_{23}$. This alters the octant sensitvity of DUNE, favorably (unfavorably) for true ${\theta }_{23}$ in the lower (higher) octant. The effect of a decaying neutrino does not alter the hierarchy or CP discovery sensitivity of DUNE in a discernible way.

    hep-phJHEP(2018)·44 citations
20. 20*

    Extracting dark matter signatures from atomic clock stability measurements

    Tigran Kalaydzhyan🇺🇸 · Nan Yu🇺🇸

    We analyze possible effects of the dark matter environment on the atomic clock stability measurements. The dark matter is assumed to exist in a form of waves of ultralight scalar fields or in a form of topological defects (monopoles and strings). We identify dark matter signal signatures in clock Allan deviation plots that can be used to constrain the dark matter coupling to the Standard Model fields. The existing data on the Al+/Hg+ clock comparison are used to put new limits on the dilaton dark matter in the region of masses m > 10^{-15} eV. We also estimate the sensitivities of future atomic clock experiments in space, including the cesium microwave and strontium optical clocks aboard the International Space Station, as well as a potential nuclear clock. These experiments are expected to put new limits on the topological dark matter in the range of masses 10^{-10} eV < m < 10^{-6} eV.

    hep-phastro-ph.HEgr-qcphysics.atom-ph+1PRD(2017)·27 citations
21. 21*

    Warm Dark Matter Galaxies with Central Supermassive Black-Holes

    Hector J. de Vega🇫🇷 · Norma G. Sanchez (CNRS Paris SU PSL OP, Chalonge-de Vega International School Center)🇫🇷

    We generalize the Thomas-Fermi approach to galaxy structure to include self-consistently and non-linearly central supermassive black holes. This approach naturally incorporates the quantum pressure of the warm dark matter (WDM) particles and shows its full powerful and clearness in the presence of supermassive black holes (SPMHs). We find the main galaxy and central black hole magnitudes: halo radius r_h , halo mass M_h, black hole mass M_BH, velocity dispersion, phase space density, with their realistic astrophysical values, masses and sizes over a wide galaxy range. The SMBH masses arise naturally in this framework. Our extensive numerical calculations and detailed analytic resolution show that with SMBH's, both WDM regimes: classical (Boltzmann dilute) and quantum (compact) do necessarily co-exist in any galaxy: from the smaller and compact galaxies to the largest ones. The transition from the quantum to the classical region occurs precisely at the same point r_A where the chemical potential vanishes. A novel halo structure with three regions shows up: A small quantum compact core of radius r_A around the SMBH, followed by a less compact region till the BH influence radius r_i, and then for r> r_i the known halo galaxy shows up with its astrophysical size. Three representative families of galaxy plus central SMBH solutions are found and analyzed:small, medium and large galaxies having SMBH masses of 10^5, 10^7 and 10^9 M_sun respectively. A minimum galaxy size and mass ~ 10^7 M_sun larger than the one without SMBH is found. Small galaxies in the range 10^4 M_sun < M_h < 10^7 M_sun cannot harbor central SMBHs. We find novel scaling M_BH - r_h - M_h relations. The galaxy equation of state is derived: The pressure P(r) takes huge values in the SMBH vecinity and then sharply decreases entering the classical region following a local perfect gas behaviour.(Abridged)

    ↳ astro-ph.GAgr-qchep-phhep-thUniverse(2022)·12 citations
22. 22*

    Primordial black hole constraints for extended mass functions

    Bernard Carr🇬🇧 · Martti Raidal🇪🇪 · Tommi Tenkanen🇬🇧 · Ville Vaskonen🇪🇪 · Hardi Veermäe🇪🇪

    We revisit the cosmological and astrophysical constraints on the fraction of the dark matter in primordial black holes (PBHs) with an extended mass function. We consider a variety of mass functions, all of which are described by three parameters: a characteristic mass and width and a dark matter fraction. Various observations then impose constraints on the dark matter fraction as a function of the first two parameters. We show how these constraints relate to those for a monochromatic mass function, demonstrating that they usually become more stringent in the extended case than the monochromatic one. Considering only the well-established bounds, and neglecting the ones that depend on additional astrophysical assumptions, we find that there are three mass windows, around $4\times 10^{-17}{M}_{\odot },$ $2\times 10^{-14}{M}_{\odot }$ and $25-100M_{\odot }$, where PBHs can constitute all dark matter. However, if one includes all the bounds, PBHs can only constitute of order $10\%$ of the dark matter.

    ↳ astro-ph.COhep-phPRD(2017)·532 citations
23. 23*

    Measuring the effects of Loop Quantum Cosmology in the CMB data

    Spyros Basilakos🇬🇷 · Vahid Kamali🇮🇷 · Ahmad Mehrabi🇮🇷

    In this Essay we investigate the observational signatures of Loop Quantum Cosmology (LQC) in the CMB data. First, we concentrate on the dynamics of LQC and we provide the basic cosmological functions. We then obtain the power spectrum of scalar and tensor perturbations in order to study the performance of LQC against the latest CMB data. We find that LQC provides a robust prediction for the main slow-roll parameters, like the scalar spectral index and the tensor-to-scalar fluctuation ratio, which are in excellent agreement within $1\sigma$ with the values recently measured by the Planck collaboration. This result indicates that LQC can be seen as an alternative scenario with respect to that of standard inflation.

    ↳ gr-qcastro-ph.COhep-phhep-thInt.J.Mod.Phys.D(2017)·6 citations
24. 24*

    Multi-field effects in a simple extension of $R^2$ inflation

    Taro Mori🇯🇵 · Kazunori Kohri🇯🇵 · Jonathan White🇯🇵

    We consider inflation in the system containing a Ricci scalar squared term and a canonical scalar field with quadratic mass term. In the Einstein frame this model takes the form of a two-field inflation model with a curved field space, and under the slow-roll approximation contains four free parameters corresponding to the masses of the two fields and their initial positions. We investigate how the inflationary dynamics and predictions for the primordial curvature perturbation depend on these four parameters. Our analysis is based on the $\delta N$ formalism, which allows us to determine predictions for the non-Gaussianity of the curvature perturbation as well as for quantities relating to its power spectrum. Depending on the choice of parameters, we find predictions that range from those of $R^2$ inflation to those of quadratic chaotic inflation, with the non-Gaussianity of the curvature perturbation always remaining small. Using our results we are able to put constraints on the masses of the two fields.

    ↳ astro-ph.COhep-phhep-thJCAP(2017)·27 citations
25. 25*

    Spectral shapes of forbidden argon beta decays as background component for rare-event searches

    J. Kostensalo🇫🇮 · J. Suhonen🇫🇮 · K. Zuber🇩🇪

    The spectral shape of the electrons from the two first-forbidden unique beta- decays of Ar-39 and Ar-42 were calculated for the first time to the next-to-leading order. Especially the spectral shape of the Ar-39 decay can be used to characterise this background component for dark matter searches based on argon. Alternatively, due to the low thresholds of these experiments, the spectral shape can be investigated over a wide energy range with high statistics and thus allow a sensitive comparison with the theoretical predictions. This might lead to interesting results for the ratio of the weak vector and axial-vector constants in nuclei.

    ↳ nucl-thhep-phnucl-exJ.Phys.G(2018)·11 citations
26. 26*

    Affine Inflation

    Hemza Azri🇹🇷 · Durmus Demir🇹🇷

    Affine gravity, a gravity theory based on affine connection with no notion of metric, supports scalar field dynamics only if scalar fields have non-vanishing potential. The non-vanishing vacuum energy ensures that the cosmological constant is non-vanishing. It also ensures that the energy-momentum tensor of vacuum gives the dynamically generated metric tensor. We construct this affine setup and study primordial inflation in it. We study inflationary dynamics in affine gravity and general relativity, comparatively. We show that non-minimally coupled inflaton dynamics can be transformed into a minimally-coupled one with a modified potential. We also show that there is one unique frame in affine gravity, as opposed to the Einstein and Jordan frames in general relativity. Future observations with higher accuracy may be able to test the affine gravity.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2017)·57 citations
27. 27*

    On the Inflationary Perturbations of Massive Higher-Spin Fields

    Alex Kehagias (NTUA)🇬🇷 · Antonio Riotto (Univ. of Geneva)🇨🇭

    Cosmological perturbations of massive higher-spin fields are generated during inflation, but they decay on scales larger than the Hubble radius as a consequence of the Higuchi bound. By introducing suitable couplings to the inflaton field, we show that one can obtain statistical correlators of massive higher-spin fields which remain constant or decay very slowly outside the Hubble radius. This opens up the possibility of new observational signatures from inflation.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2017)·94 citations
28. 28*

    Wilsonian Ward Identities

    Oliver J. Rosten

    For conformal field theories, it is shown how the Ward identity corresponding to dilatation invariance arises in a Wilsonian setting. In so doing, several points which are opaque in textbook treatments are clarified. Exploiting the fact that the Exact Renormalization Group furnishes a representation of the conformal algebra allows dilatation invariance to be stated directly as a property of the action, despite the presence of a regulator. This obviates the need for formal statements that conformal invariance is recovered once the regulator is removed. Furthermore, the proper subset of conformal primary fields for which the Ward identity holds is identified for all dimensionalities.

    ↳ hep-thcond-mat.stat-mechhep-phEPJC(2019)·6 citations
29. 29*

    Sea Quarks Contribution to the Nucleon Magnetic Moment and Charge Radius at the Physical Point

    Raza Sabbir Sufian🇺🇸 · Yi-Bo Yang🇺🇸 · Jian Liang🇺🇸 · Terrence Draper🇺🇸 · Keh-Fei Liu🇺🇸

    We report a comprehensive analysis of the light and strange disconnected-sea quarks contribution to the nucleon magnetic moment, charge radius, and the electric and magnetic form factors. The lattice QCD calculation includes ensembles across several lattice volumes and lattice spacings with one of the ensembles at the physical pion mass. We adopt a model-independent extrapolation of the nucleon magnetic moment and the charge radius. We have performed a simultaneous chiral, infinite volume, and continuum extrapolation in a global fit to calculate results in the continuum limit. We find that the combined light and strange disconnected-sea quarks contribution to the nucleon magnetic moment is ${\mu }_M(\text{DI})=-0.022(11)(09){\mu }_N$ and to the nucleon mean square charge radius is $⟨r^2{⟩}_E\text{(DI)}=-0.019(05)(05)$ fm${}^2$ which is about $1/3$ of the difference between the $⟨r_p^2{⟩}_E$ of electron-proton scattering and that of muonic atom and so cannot be ignored in obtaining the proton charge radius in the lattice QCD calculation. The most important outcome of this lattice QCD calculation is that while the combined light-sea and strange quarks contribution to the nucleon magnetic moment is small at about $1\%$, a negative $2.5(9)\%$ contribution to the proton mean square charge radius and a relatively larger positive $16.3(6.1)\%$ contribution to the neutron mean square charge radius come from the sea quarks in the nucleon. For the first time, by performing global fits, we also give predictions of the light and strange disconnected-sea quarks contributions to the nucleon electric and magnetic form factors at the physical point and in the continuum and infinite volume limits in the momentum transfer range of $0\le Q^2\le 0.5$ GeV${}^2$.

    ↳ hep-lathep-phnucl-thPRD(2017)·25 citations
30. 30*

    Implications of hydrodynamical simulations for the interpretation of direct dark matter searches

    Nassim Bozorgnia🇳🇱 · Gianfranco Bertone🇳🇱

    In recent years, realistic hydrodynamical simulations of galaxies like the Milky Way have become available, enabling a reliable estimate of the dark matter density and velocity distribution in the Solar neighborhood. We review here the status of hydrodynamical simulations and their implications for the interpretation of direct dark matter searches. We focus in particular on: the criteria to identify Milky Way-like galaxies; the impact of baryonic physics on the dark matter velocity distribution; the possible presence of substructures like clumps, streams, or dark disks; and on the implications for the direct detection of dark matter with standard and non-standard interactions.

    ↳ astro-ph.COhep-phInt.J.Mod.Phys.A(2017)·63 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.