Wed·Dec 6, 2017Wednesday·December 6, 2017

1. 01*

   Electroweak Precision Tests in High-Energy Diboson Processes

   Roberto Franceschini🇮🇹 · Giuliano Panico🇪🇸 · Alex Pomarol🇪🇸 · Francesco Riva🇨🇭 · Andrea Wulzer🇨🇭

   A promising avenue to perform precision tests of the SM at the LHC is to measure differential cross-sections at high invariant mass, exploiting in this way the growth with the energy of the corrections induced by heavy new physics. We classify the leading growing-with-energy effects in longitudinal diboson and in associated Higgs production processes, showing that they can be encapsulated in four real "high-energy primary" parameters. We assess the reach on these parameters at the LHC and at future hadronic colliders, focusing in particular on the fully leptonic $WZ$ channel that appears particularly promising. The reach is found to be superior to existing constraints by one order of magnitude, providing a test of the SM electroweak sector at the per-mille level, in competition with LEP bounds. Unlike LHC Run-1 bounds, which only apply to new physics effects that are much larger than the SM in the high-energy tail of the distributions, the probe we study applies to a wider class of new physics scenarios where such large departures are not expected.

   hep-phJHEP(2018)·128 citations
2. 02*

   Evidence for Inflation in an Axion Landscape

   Pran Nath🇺🇸 · Maksim Piskunov🇺🇸

   We discuss inflation models within supersymmetry and supergravity frameworks with a landscape of chiral superfields and one $U(1)$ shift symmetry which is broken by non-perturbative symmetry breaking terms in the superpotential. We label the pseudo scalar component of the chiral fields axions and their real parts saxions. Thus in the models only one combination of axions will be a pseudo-Nambu-Goldstone-boson which will act as the inflaton. The proposed models constitute consistent inflation for the following reasons: The inflation potential arises dynamically with stabilized saxions, the axion decay constant can lie in the sub-Planckian region, and consistency with the Planck data is achieved. The axion landscape consisting of $m$ axion pairs is assumed with the axions in each pair having opposite charges. A fast roll--slow roll splitting mechanism for the axion potential is proposed which is realized with a special choice of the axion basis. In this basis the $2m$ coupled equations split into $2m-1$ equations which enter in the fast roll and there is one unique linear combination of the $2m$ fields which controls the slow roll and thus the power spectrum of curvature and tensor perturbations. It is shown that a significant part of the parameter space exists where inflation is successful, i.e., $N_{\mathrm{pivot}}=[50,60]$, the spectral index $n_s$ of curvature perturbations, and the ratio $r$ of the power spectrum of tensor perturbations and curvature perturbations, lie in the experimentally allowed regions given by the Planck experiment. Further, it is shown that the model allows for a significant region of the parameter space where the effective axion decay constant can lie in the sub-Planckian domain.

   hep-phastro-ph.HEhep-thJHEP(2018)·6 citations
3. 03*

   A three-site gauge model for flavor hierarchies and flavor anomalies

   Marzia Bordone🇨🇭 · Claudia Cornella🇨🇭 · Javier Fuentes-Martin🇨🇭 · Gino Isidori🇨🇭

   We present a three-site Pati-Salam gauge model able to explain the Standard Model flavor hierarchies while, at the same time, accommodating the recent experimental hints of lepton-flavor non-universality in $B$ decays. The model is consistent with low- and high-energy bounds, and predicts a rich spectrum of new states at TeV scale that could be probed in the near future by the high-$p_T$ experiments at the LHC.

   hep-phPLB(2018)·338 citations
4. 04*

   Higgs and superparticle mass predictions from the string theory landscape

   Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Hasan Serce🇺🇸 · Kuver Sinha🇺🇸

   Predictions for the scale of SUSY breaking from the string landscape go back at least a decade to the work of Denef and Douglas on the statistics of flux vacua. The assumption that an assortment of SUSY breaking F and D terms are present in the hidden sector, and their values are uniformly distributed in the landscape of D=4, N=1 effective supergravity models, leads to the expectation that the landscape pulls towards large values of soft terms favored by a power law behavior P(m(soft))~ m(soft)^n. On the other hand, similar to Weinberg's prediction of the cosmological constant, one can assume an anthropic selection of weak scales not too far from the measured value characterized by m(W,Z,h)~ 100 GeV. Working within a fertile patch of gravity-mediated low energy effective theories where the superpotential mu term is << m(3/2), as occurs in models such as radiative breaking of Peccei-Quinn symmetry, this biases statistical distributions on the landscape by a cutoff on the parameter Delta(EW), which measures fine-tuning in the m(Z)-mu mass relation. The combined effect of statistical and anthropic pulls turns out to favor low energy phenomenology that is more or less agnostic to UV physics. While a uniform selection n=0 of soft terms produces too low a value for m(h), taking n=1 or 2 produce most probabilistically m(h)~125 GeV for negative trilinear terms. For n>=1, there is a pull towards split generations with m(squarks,sleptons)(1,2)~10-30 TeV whilst m(t1)~ 1-2 TeV. The most probable gluino mass comes in at ~ 3-4 TeV--apparently beyond the reach of HL-LHC (although the required quasi-degenerate higgsinos should still be within reach). We comment on consequences for SUSY collider and dark matter searches.

   hep-phhep-thJHEP(2018)·48 citations
5. 05*

   Strong coupling constants of negative parity heavy baryons with $\pi$ and $K$ mesons

   T.M.Aliev🇹🇷 · S.Bilmis🇹🇷 · M.Savci🇹🇷

   The strong coupling constants of negative parity heavy baryons belonging to a sextet and antitriplet representations of $S{U}_f(3)$ with light $\pi$ and $K$ mesons are estimated within the light cone QCD sum rules. It is observed that each class of the sextet-sextet, sextet-antitriplet, and antitriplet-antitriplet transitions can be described by only one corresponding function. The pollutions arising from the positive to positive, positive to negative, and negative to positive parity baryons transitions are eliminated by constructing sum rules for different Lorentz structures. The obtained coupling constants are compared with the ones for the positive parity heavy baryons.

   hep-phAdv.High Energy Phys.(2017)·3 citations
6. 06*

   $R_{K^{(\ast )}}$ and $R(D^{(\ast )})$ anomalies resolved with lepton mixing

   Debajyoti Choudhury🇮🇳 · Anirban Kundu🇮🇳 · Rusa Mandal🇮🇳 · Rahul Sinha🇮🇳

   In a recent paper arXiv:1706.08437, we have advanced a minimal resolution of some of the persistent anomalies in semileptonic $B$-decays. These include the neutral-current observables $R_K$ and $R_{K^{\ast }}$, as well as the charged-current observables $R(D)$ and $R(D^{\ast })$. Recently, it has been observed that the semileptonic decays of the $B_c$ meson also hint at a similar type of anomaly. In this longer version, we discuss in detail why, if the anomalies are indeed there, it is a challenging task to explain the data consistently in terms of a simple and compelling new physics scenario. We find that the minimal scheme to achieve a reasonable fit involves the inclusion of just two (or, at worst, three with a possible symmetry relationship between their Wilson coefficients) new current-current operators, constructed in terms of the flavour eigenstates, augmented by a change of basis for the charged lepton fields. With only three unknown parameters, this class of models not only explain all the anomalies (including that in $B_c\to J/\psi \ell \nu$) to a satisfactory level but also predict some interesting signatures, like $B\to K\mu \tau$, $B_s\to \tau \tau$, or $B\to K$ plus missing energy, that can be observed at LHCb or Belle-II.

   hep-phNPB(2018)·28 citations
7. 07*

   Effects of Renormalizing the chiral SU(2) Quark-Meson-Model

   Andreas Zacchi🇩🇪 · Jürgen Schaffner-Bielich🇩🇪

   We investigate the restoration of chiral symmetry at finite temperature in the SU(2) quark meson model where the mean field approximation is compared to the renormalized version for quarks and mesons. In a combined approach at finite temperature all the renormalized versions show a crossover transition. The inclusion of different renormalization scales leave the order parameter and the mass spectra nearly untouched, but strongly influence the thermodynamics at low temperatures and around the phase transition. We find unphysical results for the renormalized version of mesons and the combined one.

   hep-phnucl-thPRD(2018)·18 citations
8. 08*

   Higgs Pair Productions in the CP-violating Two-Higgs-Doublet Model

   Ligong Bian🇨🇳 · Ning Chen🇨🇳 · Yun Jiang🇩🇰

   The SM-like Higgs pair productions are discussed in the framework of the general CP-violating two-Higgs-doublet model, where we find the CP-violating mixing angles can be related to the Higgs self couplings. Therefore, the future experimental searches for Higgs boson pairs can be constrained by the improved precision of the electric dipole moment measurements. Based on a series constraints of the SM-like Higgs boson signal fits, the perturbative unitarity and stability bounds to the Higgs potential, and the most recent LHC searches for the heavy Higgs bosons, we suggest a set of benchmark models for the future high-energy collider searches for the Higgs pair productions. The $e^{+}{e}^{-}$ colliders operating at $\sqrt{s}=$ (500 GeV, 1 TeV) are capable of measuring the Higgs cubic self couplings of the benchmark models directly. We also estimate the cross sections of the resonance contributions to the Higgs pair productions for the benchmark models at the future LHC and SppC/Fcc-hh runs.

   hep-phInt.J.Mod.Phys.A(2017)·4 citations
9. 09*

   Neutrinos, DUNE and the world best bound on CPT invariance

   Gabriela Barenboim🇪🇸 · Christoph Andreas Ternes🇪🇸 · Mariam Tórtola🇪🇸

   CPT symmetry, the combination of Charge Conjugation, Parity and Time reversal, is a cornerstone of our model building strategy and therefore the repercussions of its potential violation will severely threaten the most extended tool we currently use to describe physics, i.e. local relativistic quantum fields. However, limits on its conservation from the Kaon system look indeed imposing. In this work we will show that neutrino oscillation experiments can improve this limit by several orders of magnitude and therefore are an ideal tool to explore the foundations of our approach to Nature. Strictly speaking testing CPT violation would require an explicit model for how CPT is broken and its effects on physics. Instead, what is presented in this paper is a test of one of the predictions of CPT conservation, i.e., the same mass and mixing parameters in neutrinos and antineutrinos. In order to do that we calculate the current CPT bound on all the neutrino mixing parameters and study the sensitivity of the DUNE experiment to such an observable. After deriving the most updated bound on CPT from neutrino oscillation data, we show that, if the recent T2K results turn out to be the true values of neutrino and antineutrino oscillations, DUNE would measure the fallout of CPT conservation at more than 3$\sigma$. Then, we study the sensitivity of the experiment to measure CPT invariance in general, finding that DUNE will be able to improve the current bounds on $\Delta (\Delta m_{31}^2)$ by at least one order of magnitude. We also study the sensitivity to the other oscillation parameters. Finally we show that, if CPT is violated in nature, combining neutrino with antineutrino data in oscillation analysis will produce imposter solutions.

   hep-phhep-exPLB(2018)·61 citations
10. 10*

    Multiparton interactions, small-x processes and diffraction

    F. Hautmann🇬🇧 · H. Jung🇩🇪

    The connection between multiparton interaction, diffractive processes and saturation effects is discussed. The relation of the rise of the gluon density at small longitudinal momentum fractions x with the occurrence of saturation, diffraction and multiparton interaction is being studied both experimentally and theoretically. We illustrate key ideas underlying recent progress, and stress the role of different theoretical approaches to small-x QCD evolution in investigations of multiparton interactions.

    hep-phAdv.Ser.Direct.High Energy Phys.(2018)·3 citations
11. 11*

    Global analysis on determination of fracture functions considering sea quark asymmetries in the nucleon

    Samira Shoeibi🇮🇷 · F. Taghavi-Shahri🇮🇷 · Kurosh Javidan🇮🇷

    Several experiments at the electron-proton ($ep$) collider HERA have collected high precision data on the spectrum of leading-proton and leading-neutron carrying a large fraction of the proton's energy. In this paper, we have analyzed recent experimental data on the production of leading-nucleon in deep inelastic scattering (DIS) processes at HERA in the framework of a perturbative QCD (pQCD). An approach based on the fractures functions framework has been used, and the nucleon fracture functions (nucleon FFs) ${\mathcal{M}}_2^{(n/p)}(x,Q^2,x_L)$ have been extracted from global QCD analysis of DIS data measured by ZEUS collaboration at HERA. We show that the approach of fracture functions formalisem allows us phenomenologically parametrize the nucleon FFs at the input scale, $Q_0^2$. Considering leading-nucleon production data in the DIS processes, we present the results for the separate parton distributions for all parton species. The extracted results from the $t$-integrated leading-baryon fracture functions, $F_2^{\mathrm{LB}(3)}(x,Q^2,x_L)$ are in good agreement with all DIS data analyzed, for a wide range of longitudinal momentum fraction $x_L$ as well as scaled fractional momentum variable $x$.

    hep-phhep-exPoS(2018)·0 citations
12. 12*

    Diffuse axion-like particle searches

    Hendrik Vogel🇺🇸 · Ranjan Laha🇩🇪 · Manuel Meyer🇺🇸

    We propose a new method to search for axion-like particles (ALPs) based on the gamma-rays produced concomitant with high-energy astrophysical neutrinos. The existence of high-energy neutrinos implies production of gamma-rays in the same sources. Photons can convert into ALPs in the sources' magnetic fields, and will travel as ALPs through extragalactic space. Back-conversion in the Milky Way's magnetic field leads to a diffuse anisotropic high-energy photon flux that existing and upcoming gamma-ray detectors, like HAWC, CTA, and LHAASO can detect. This method probes unexplored ALP parameter space, with LHAASO being realistically sensitive to couplings above $10^{-11}\mathrm{Ge}{\mathrm{V}}^{-1}$ and masses up to $3\times 10^{-6}\mathrm{eV}$ in ten years. Our technique also explores viable ALP dark matter parameter space.

    hep-phastro-ph.COastro-ph.HEhep-ex+1PoS(2019)·35 citations
13. 13*

    Anomalous $Z^{\prime }$ and Diboson Resonances at the LHC

    Ahmed Ismail🇺🇸 · Andrey Katz🇨🇭

    We propose novel collider searches which can significantly improve the LHC reach to new gauge bosons $Z^{\prime }$ with mixed anomalies with the electroweak (EW) gauge group. Such a $Z^{\prime }$ necessarily acquires a Chern-Simons coupling to the EW gauge bosons and these couplings can drive both exotic $Z$ decays into $Z^{\prime }\gamma$ if the new gauge boson is sufficiently light, as well as $Z^{\prime }$ decays into EW gauge bosons.While the exotic decay rate of the heavy $Z$ into $Z^{\prime }\gamma$ is too small to be observed at the LHC, for a light $Z^{\prime }$, we show the potential of a lepton jet search in association with a photon to probe the rare decay $Z\to Z^{\prime }\gamma$.

    hep-phhep-exJHEP(2018)·24 citations
14. 14*

    Protecting the Axion with Local Baryon Number

    Michael Duerr🇩🇪 · Kai Schmidt-Hoberg🇩🇪 · James Unwin🇺🇸

    The Peccei-Quinn (PQ) solution to the Strong CP Problem is expected to fail unless the global symmetry U(1)${}_{\mathrm{PQ}}$ is protected from Planck-scale operators up to high mass dimension. Suitable protection can be achieved if the PQ symmetry is an automatic consequence of some gauge symmetry. We highlight that if baryon number is promoted to a gauge symmetry, the exotic fermions needed for anomaly cancellation can elegantly provide an implementation of the Kim-Shifman-Vainshtein-Zakharov 'hidden axion' mechanism with a PQ symmetry protected from Planck-scale physics.

    hep-phPLB(2018)·37 citations
15. 15*

    The Flavor-locked Flavorful Two Higgs Doublet Model

    Wolfgang Altmannshofer🇺🇸 · Stefania Gori🇺🇸 · Dean J. Robinson🇺🇸 · Douglas Tuckler🇺🇸

    We propose a new framework to generate the Standard Model (SM) quark flavor hierarchies in the context of two Higgs doublet models (2HDM). The `flavorful' 2HDM couples the SM-like Higgs doublet exclusively to the third quark generation, while the first two generations couple exclusively to an additional source of electroweak symmetry breaking, potentially generating striking collider signatures. We synthesize the flavorful 2HDM with the `flavor-locking' mechanism, that dynamically generates large quark mass hierarchies through a flavor-blind portal to distinct flavon and hierarchon sectors: Dynamical alignment of the flavons allows a unique hierarchon to control the respective quark masses. We further develop the theoretical construction of this mechanism, and show that in the context of a flavorful 2HDM-type setup, it can automatically achieve realistic flavor structures: The CKM matrix is automatically hierarchical with $|V_{cb}|$ and $|V_{ub}|$ generically of the observed size. Exotic contributions to meson oscillation observables may also be generated, that may accommodate current data mildly better than the SM itself.

    hep-phJHEP(2018)·39 citations
16. 16*

    Consistency of perturbed Tribimaximal, Bimaximal and Democratic mixing with Neutrino mixing data

    Sumit K. Garg🇮🇳

    We scrutinize corrections to tribimaximal (TBM), bimaximal (BM) and democratic (DC) mixing matrices for explaining recent global fit neutrino mixing data. These corrections are parameterized in terms of small orthogonal rotations (R) with corresponding modified PMNS matrices of the forms \big($R_{ij}^l\cdot U,U\cdot R_{ij}^r,U\cdot R_{ij}^r\cdot R_{kl}^r,R_{ij}^l\cdot R_{kl}^l\cdot U$\big ) where $R_{ij}^{l,r}$ is rotation in ij sector and U is any one of these special matrices. We showed that for perturbative schemes dictated by single rotation, only \big($R_{12}^l\cdot U_{BM},R_{13}^l\cdot U_{BM},U_{TBM}\cdot R_{13}^r$ \big ) can fit the mixing data at $3\sigma$ level. However for $R_{ij}^l\cdot R_{kl}^l\cdot U$ type rotations, only \big ($R_{23}^l\cdot R_{13}^l\cdot U_{DC}$\big ) is successful to fit all neutrino mixing angles within $1\sigma$ range. For $U\cdot R_{ij}^r\cdot R_{kl}^r$ perturbative scheme, only \big($U_{BM}\cdot R_{12}^r\cdot R_{13}^r$,~$U_{DC}\cdot R_{12}^r\cdot R_{23}^r$,~$U_{TBM}\cdot R_{12}^r\cdot R_{13}^r$\big ) are consistent at $1\sigma$ level. The remaining double rotation cases are either excluded at 3$\sigma$ level or successful in producing mixing angles only at $2\sigma -3\sigma$ level. We also updated our previous analysis on PMNS matrices of the form \big($R_{ij}\cdot U\cdot R_{kl}$\big ) with recent mixing data. We showed that the results modifies substantially with fitting accuracy level decreases for all of the permitted cases except \big($R_{12}\cdot U_{BM}\cdot R_{13}$, $R_{23}\cdot U_{TBM}\cdot R_{13}$ and $R_{13}\cdot U_{TBM}\cdot R_{13}$\big ) in this rotation scheme.

    hep-phNPB(2018)·14 citations
17. 17*

    Study of $B_c\to DS$ Decays in PQCD Approach

    Zhi-Tian Zou🇨🇳 · Ying Li🇨🇳 · Xin Liu🇨🇳

    Within the framework of perturbative QCD approach based on $k_T$ factorization, we studied 40 $B_c\to DS$ decay modes in the leading order and leading power, where "S" stands for the light scalar meson. Under two different scenarios (S1 and S2) for the description of scalar mesons, we explored the branching fractions and related CP asymmetries. As a heavy meson consisting of two heavy quarks with different flavor, the light-cone distribution amplitude of $B_c$ meson has not been well defined, so the $\delta$-function is adopted. The contributions of emission diagrams are suppressed by the vector decay constants and CKM elements, the contributions of annihilation are dominant. After the calculation, we found some branching fractions are in the range of $[10^{-5},10^{-4}]$, which could be measured in the current LHCb experiment, and other decays with smaller branching fractions will be tested at the high-energy colliders in future. Furthermore, some decay modes have large CP asymmetries, but they are unmeasurable currently due to the small branching fractions.

    hep-phhep-exPRD(2018)·14 citations
18. 18*

    Emergence of the mass discrepancy-acceleration relation from dark matter-baryon interactions

    Benoit Famaey🇫🇷 · Justin Khoury🇺🇸 · Riccardo Penco🇺🇸

    The observed tightness of the mass discrepancy-acceleration relation (MDAR) poses a fine-tuning challenge to current models of galaxy formation. We propose that this relation could arise from collisional interactions between baryons and dark matter (DM) particles, without the need for modification of gravity or ad hoc feedback processes. We assume that these interactions satisfy the following three conditions: (i) the relaxation time of DM particles is comparable to the dynamical time in disk galaxies; (ii) DM exchanges energy with baryons due to elastic collisions; (iii) the product between the baryon-DM cross section and the typical energy exchanged in a collision is inversely proportional to the DM number density. We present an example of a particle physics model that gives a DM-baryon cross section with the desired density and velocity dependence. Direct detection constraints require our DM particles to be either very light ($m<<m_b$) or very heavy ($m>>m_b$), corresponding respectively to heating and cooling of DM by baryons. In both cases, our mechanism applies and an equilibrium configuration can in principle be reached. Here, we focus on the heavy DM/cooling case as it is technically simpler. Under these assumptions, we find that rotationally-supported disk galaxies could naturally settle to equilibrium configurations satisfying a MDAR at all radii without invoking finely tuned feedback processes. We also discuss issues related to the small scale clumpiness of baryons, as well as predictions for pressure-supported systems. We argue in particular that galaxy clusters do not follow the MDAR despite being DM-dominated because they have not reached their equilibrium configuration. Finally, we revisit existing phenomenological, astrophysical and cosmological constraints on baryon-DM interactions in light of the unusual density dependence of the cross section.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phJCAP(2018)·35 citations
19. 19*

    Muoproduction of exotic charmonia at COMPASS

    A. Guskov (on behalf of the COMPASS Collaboration)🇷🇺

    Exotic charmonium-like states have been targeted by various experiments in the last 15 years, but their nature still is unknown. Photo-(muo)production is a new promising instrument to study them. COMPASS, a fixed target experiment at CERN, analyzed the full set of the data collected with a muon beam between 2002 and 2011, covering the range from 7 GeV to 19 GeV in the centre-of-mass energy of the (virtual)photon-nucleon system. Production of the X(3872) state in the reaction ${\mu }^{+}N\to {\mu }^{+}(J/\psi {\pi }^{+}{\pi }^{-}){\pi }^{\pm }{N}^{\prime }$ has been observed with a statistical significance of around 5 $\sigma$. The shape of the ${\pi }^{+}{\pi }^{-}$ mass distribution from the decay $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ shows disagreement with previous observations. The product of the cross section and the branching fraction of the $X(3872)$ decay into $J/\psi \pi \pi$ is estimated as 71$\pm$28(stat)$\pm$39(syst) pb. The results obtained for the production of the $Z_c^{\pm }(3900)$ are also reported as well as future perspectives.

    ↳ hep-exhep-phPoS(2018)·2 citations
20. 20*

    The Pursuit of Dark Matter at Colliders - An Overview

    Bjoern Penning🇺🇸

    Dark matter is one of the main puzzles in fundamental physics and the goal of a diverse, multi-pronged research program. Underground and astrophysical searches search for dark matter particles in the cosmos, either by interacting directly or by searching for dark matter annihilation. Particle colliders, in contrast, might produce dark matter in the laboratory and are able to probe all basic interactions. They are sensitive to low dark matter masses, provide complementary information at higher masses and are subject to different systematic uncertainties. Collider searches are therefore an important part of an inter- disciplinary dark matter search strategy. This article highlights the experimental and phenomenological development in collider dark matters searches of recent years and their connection with the wider field.

    ↳ hep-exhep-phJ.Phys.G(2018)·72 citations
21. 21*

    Gravitational-Wave Fringes at LIGO: Detecting Compact Dark Matter by Gravitational Lensing

    Sunghoon Jung🇰🇷 · Chang Sub Shin🇰🇷

    Utilizing gravitational-wave (GW) lensing opens a new way to understand the small-scale structure of the universe. We show that, in spite of its coarse angular resolution and short duration of observation, LIGO can detect the GW lensing induced by compact structures, in particular by compact dark matter (DM) or primordial black holes of $10-10^5{M}_{\odot }$, which remain interesting DM candidates. The lensing is detected through GW frequency chirping, creating the natural and rapid change of lensing patterns: \emph{frequency-dependent amplification and modulation} of GW waveforms. As a highest-frequency GW detector, LIGO is a unique GW lab to probe such light compact DM. With the design sensitivity of Advanced LIGO, one-year observation by three detectors can optimistically constrain the compact DM density fraction $f_{\mathrm{DM}}$ to the level of a few percent.

    ↳ astro-ph.COgr-qchep-phPRL(2019)·176 citations
22. 22*

    Value of the axial-vector coupling strength in $\beta$ and $\beta \beta$ decays: A review

    Jouni Suhonen🇫🇮

    In this review the quenching of the weak axial-vector coupling strength, $g_{\mathrm{A}}$, is discussed in nuclear $\beta$ and double-$\beta$ decays. On one hand, the nuclear-medium and nuclear many-body effects are separated, and on the other hand the quenching is discussed from the points of view of different many-body methods and different $\beta$-decay and double-$\beta$-decay processes. Both the historical background and the present status are reviewed and contrasted against each other. The theoretical considerations are tied to performed and planned measurements, and possible new measurements are urged, whenever relevant and doable. Relation of the quenching problem to the measurements of charge-exchange reactions and muon-capture rates is pointed out.

    ↳ nucl-thhep-phFront.in Phys.(2017)·212 citations
23. 23*

    The Chiral Separation Effect in quenched finite-density QCD

    M. Puhr🇩🇪 · P. V. Buividovich🇩🇪

    We present results of a study of the Chiral Separation Effect (CSE) in quenched finite-density QCD. Using a recently developed numerical method we calculate the conserved axial current for exactly chiral overlap fermions at finite density for the first time. We compute the anomalous transport coefficient for the CSE in the confining and de-confining phase and investigate possible deviations from the universal value. In both phases we find that non-perturbative corrections to the CSE are absent and we reproduce the universal value for the transport coefficient within small statistical errors. Our results suggest that the CSE can be used to determine the renormalisation factor of the axial current.

    ↳ hep-lathep-phhep-thEPJ Web Conf.(2018)·1 citation
24. 24*

    CP violation in $b$ hadrons at LHCb

    A. Hicheur🇧🇷

    The most recent results on CP violation in $b$ hadrons obtained by the LHCb Collaboration with Run I and years 2015-2016 of Run II are reviewed. The different types of violation are covered by the studies presented in this paper.

    ↳ hep-exhep-phInt.J.Mod.Phys.Conf.Ser.(2018)·0 citations
25. 25*

    A modification of Faddeev-Popov approach free from Gribov ambiguity

    Chong-yao Chen🇨🇳 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳

    We propose a modified version of the Faddeev-Popov quantization approach for non-Abelian gauge field theory to avoid the Gribov ambiguity. We show that by means of introducing a new method to insert the correct identity into the Yang-Mills generating functional and considering the identity generated by an integral through a subgroup of the gauge group, the problem of the Gribov ambiguity can be removed naturally. Meanwhile by handling the absolute value of the Faddeev-Popov determinant with the method introduced by Williams and collaborators, we lift the Jacobian determinant together with the absolute value and obtain a local Lagrangian. The new Lagrangian have a nilpotent symmetry which can be viewed as an analogue of the BRST symmetry.

    ↳ hep-thhep-phnucl-thCommun.Theor.Phys.(2020)·1 citation
26. 26*

    Dark Matter Annihilation from Nearby Ultra-compact Micro Halos to Explain the Tentative Excess at ~1.4 TeV in DAMPE data

    Fengwei Yang🇨🇳 · Meng Su🇨🇳 · Yue Zhao🇨🇳

    The tentative 1.4 TeV excess in the $e^{+}{e}^{-}$ spectrum measured by The DArk Matter Particle Explorer (DAMPE) motivates the possible existence of one or more local dark matter concentrated regions. In particular, Ultra-compact Micro Halos (UCMHs) seeded by large density perturbations in the early universe, allocated within ~0.3 kpc from the solar system, could provide the potential source of electrons and positrons produced from dark matter annihilation, enough to explain the DAMPE signal. Here we consider a UCMH with density profile assuming radial in-fall and explore the preferred halo parameters to explain the 1.4 TeV "DAMPE excess". We find that typical parameter space of UCMHs can easily explain the "DAMPE excess" with usual thermal-averaged annihilation cross section of WIMP. The fraction of dark matter stored in such UCMHs in the Galactic-scale halo can be reduced to as small as $O(10^{-5})$, well within the current cosmological and astrophysical constraints.

    ↳ astro-ph.HEastro-ph.COhep-ph42 citations
27. 27*

    Instant Preheating in Quintessential Inflation with $\alpha$-Attractors

    Konstantinos Dimopoulos🇬🇧 · Leonora Donaldson Wood🇬🇧 · Charlotte Owen🇬🇧

    We investigate a compelling model of quintessential inflation in the context of $\alpha$-attractors, which naturally result in a scalar potential featuring two flat regions, the inflationary plateau and the quintessential tail. The "asymptotic freedom" of $\alpha$-attractors, near the kinetic poles, suppresses radiative corrections and interactions, which would otherwise threaten to lift the flatness of the quintessential tail and cause a 5th-force problem respectively. Since this is a non-oscillatory inflation model, we reheat the Universe through instant preheating. The parameter space is constrained by both inflation and dark energy requirements. We find an excellent correlation between the inflationary observables and model predictions, in agreement with the $\alpha$-attractors set-up. We also obtain successful quintessence for natural values of the parameters. Our model predicts potentially sizeable tensor perturbations (at the level of 1%) and a slightly varying equation of state for dark energy, to be probed in the near future.

    ↳ astro-ph.COhep-phhep-thPRD(2018)·111 citations
28. 28*

    Hidden sector searches with SHiP and NA62

    P. Mermod (for the SHiP Collaboration)🇨🇭

    High-intensity proton beams impinging on a fixed target or beam dump allow to probe new physics via the production of new weakly-coupled particles in hadron decays. The CERN SPS provides opportunities to do so with the running NA62 experiment and the planned SHiP experiment. Reconstruction of kaon decay kinematics (beam mode) allows NA62 to probe for the existence of right-handed neutrinos and dark photons with masses below 0.45 GeV. Direct reconstruction of displaced vertices from the decays of new neutral particles (dump mode) will allow NA62 and SHiP to probe right-handed neutrinos with masses up to 5 GeV and mixings down to several orders of magnitude smaller than current constraints, in regions favoured in models which explain at once neutrino masses, matter-antimatter asymmetry and dark matter.

    ↳ hep-exhep-phPoS(2017)·29 citations
29. 29*

    Machine learning as an instrument for data unfolding

    Alexander Glazov🇩🇪

    A method for correcting for detector smearing effects using machine learning techniques is presented. Compared to the standard approaches the method can use more than one reconstructed variable to infere the value of the unsmeared quantity on event by event basis. The method is implemented using a sequential neural network with a categorical cross entropy as the loss function. It is tested on a toy example and is shown to satisfy basic closure tests. Possible application of the method for analysis of the data from high energy physics experiments is discussed.

    ↳ physics.data-anhep-exhep-ph25 citations
30. 30*

    Gravitational Waves Probes of Parity Violation in Compact Binary Coalescence

    Stephon H. Alexander🇺🇸 · Nicolas Yunes🇺🇸

    Is gravity parity violating? Given the recent observations of gravitational waves from coalescing compact binaries, we develop a strategy to find an answer with current and future detectors. We identify the key signatures of parity violation in gravitational waves: amplitude birefringence in their propagation and a modified chirping rate in their generation. We then determine the optimal binaries to test the existence of parity violation in gravity, and prioritize the research in modeling that will be required to carry out such tests before detectors reach their design sensitivity.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2018)·91 citations
31. 31*

    Conformal Higgs Gravity

    Meir Shimon🇮🇱

    It is shown that gravitation naturally emerges from the standard model of particle physics if local scale invariance is imposed in the context of a single conformal (Weyl-symmetric) theory. Gravitation is then conformally-related to the standard model via a conformal transformation, merely a function of the number of fermionic particles dominating the energy density associated with the ground state of the physical system. Doing so resolves major puzzles afflicting the standard models of particle physics and cosmology, clearly indicating these to be artifacts stemming from universally employing the system of units selected here and now. In addition to the three known fundamental interactions mediated by gauge bosons, a scalar-tensor interaction is also accommodated by the theory; its inertial and gravitational sectors are characterized by whether contributions to the Weyl tensor vanish or are finite, respectively. In this approach both inertia and gravity are viewed as collective phenomena, with characteristic gravitational Planck scale devoid of fundamental meaning; consequently, mass hierarchy and Higgs mass instability concerns are avoided altogether. Only standard model particles gravitate; dark matter and dark energy have an inertial origin, and since the Higgs field does not interact with photons it is an ideal candidate for explaining the dark sector of cosmology. On cosmological scales the dynamical vacuum-like Higgs self-coupling accounts for dark energy, and its observed proximity at present to the energy density of nonrelativistic matter is merely a consistency requirement. Spatially varying vacuum expectation value of the Higgs field could likely account for the apparent cold dark matter on both galactic and cosmological scales.

    ↳ gr-qcastro-ph.COhep-phhep-th1 citation

* 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.