HEP Phenomenology·hep-ph

Wed·Feb 19, 2020Wednesday·February 19, 2020

32 papers—23 primary·9 cross-listed·reconstructed*

01*
Stochastic evolution of scalar fields with continuous symmetries during inflation
Peter Adshead🇺🇸 · Lauren Pearce🇺🇸 · Jessie Shelton🇺🇸 · Zachary J. Weiner🇺🇸
During inflation, scalar fields with masses less than the Hubble scale acquire vacuum expectation values (vevs) via stochastic processes driven by quantum fluctuations. For nearly massless spectator scalars transforming nontrivially under a continuous symmetry group, we demonstrate that the evolution of the vev depends on the dimensionality of the scalar field space. Fields in larger representations both attain larger vacuum expectation values and converge more rapidly to equilibrium. We present an argument demonstrating how this higher-dimensional evolution can be obtained in unitary gauge for fields transforming under local symmetries with a mass gap that is small compared to the Hubble scale. Finally, we show that accounting for the full number of degrees of freedom in the Standard Model Higgs multiplet tightens Higgs stability constraints on the inflationary scale at the percent level and has more dramatic consequences for both the vev and the energy stored in the Higgs field after inflation.
hep-phastro-ph.COPRD(2020)·24 citations
02*
Revisit to the $b \to c τ ν$ transition: in and beyond the SM
Kingman Cheung🇹🇼 · Zhuo-Ran Huang🇫🇷 · Hua-Dong Li🇨🇳 · Cai-Dian Lü🇨🇳 · Ying-nan Mao🇹🇼 · Ru-Ying Tang🇨🇳
We perform an analysis of the $b \to c τ ν$ data, including $R (D^{(*)})$ , $R (J / ψ)$ , $P_{τ} (D^{*})$ and $F_{L}^{D^{*}}$ , within and beyond the Standard Model (SM). We fit the $B \to D^{(*)}$ hadronic form factors in the HQET parametrization to the lattice and the light-cone sum rule (LCSR) results, applying the general strong unitarity bounds corresponding to $J^{P} = 1^{-}$ , $1^{+}$ , $0^{-}$ and $0^{+}$ . Using the obtained HQET relations between helicity amplitudes, we give the strong unitarity bounds on individual helicity amplitudes, which can be used in the BGL fits. Using the fitted form factors and taking into account the most recent Belle measurement of $R (D^{(*)})$ we investigate the model-independent and the leptoquark model explanations of the $b \to c τ ν$ anomalies. Specifically, we consider the one-operator, the two-operator new physics (NP) scenarios and the NP models with a single $R_{2}$ , $S_{1}$ or $U_{1}$ leptoquark which is supposed to be able to address the $b \to c τ ν$ anomalies, and our results show that the $R_{2}$ leptoquark model is in tension with the limit $B (B_{c} \to τ ν) < 10%$ . Furthermore, we give predictions for the various observables in the SM and the NP scenarios/leptoquark models based on the present form factor study and the analysis of NP.
hep-phhep-exNPB(2021)·59 citations
03*
A covariant model for the decuplet to octet Dalitz decays
G. Ramalho🇧🇷
In the last years it became possible to measure in HADES the dilepton decays of several baryons. The baryon dilepton decays provide information about the electromagnetic structure of the baryons in the timelike region. In the present work, we study the $B^{'} \to e^{+} e^{-} B$ decays, where $B^{'}$ is a baryon decuplet member and $B$ is a baryon octet member. Our calculations are based on the covariant spectator quark model, where the contribution of the quark core is complemented with an $S U (3)$ contribution from the pion cloud. The pion cloud contribution prove to be relevant in the range of study. We present predictions for the $Σ^{0} (1385) \to e^{+} e^{-} Λ (1116)$ and $Σ^{+} (1385) \to e^{+} e^{-} Σ^{+} (1193)$ decays, which may be tested at HADES in a near future. Predictions for the remaining decuplet baryon Dalitz decays are also presented. We conclude that different orders of magnitudes are expected for the baryon decuplet Dalitz decay widths, according to the quark content of the baryons. We also conclude that the dependence of the transition form factors on the square momentum transfer ( $q^{2}$ ) is important for some transitions.
hep-phhep-exnucl-exnucl-thPRD(2020)·18 citations
04*
Fermion spectrum and $g - 2$ anomalies in a low scale 3-3-1 model
A. E. Cárcamo Hernández🇨🇱 · Yocelyne Hidalgo Velásquez🇨🇱 · Sergey Kovalenko🇨🇱 · H. N. Long🇻🇳 · Nicolás A. Pérez-Julve🇨🇱 · V. V. Vien🇻🇳
We propose a renormalizable theory based on the $S U (3)_{C} \times S U (3)_{L} \times U (1)_{X}$ gauge symmetry, supplemented by the spontaneously broken $U (1)_{L_{g}}$ global lepton number symmetry and the $S_{3} \times Z_{2}$ discrete group, which successfully describes the observed SM fermion mass and mixing hierarchy. In our model the top and exotic quarks get tree level masses, whereas the bottom, charm and strange quarks as well as the tau and muon leptons obtain their masses from a tree level Universal seesaw mechanism thanks to their mixing with charged exotic vector like fermions. The masses for the first generation SM charged fermions are generated from a radiative seesaw mechanism at one loop level. The light active neutrino masses are produced from a loop level radiative seesaw mechanism. Our model successfully accommodates the experimental values for electron and muon anomalous magnetic dipole moments.
hep-phEPJC(2021)·52 citations
05*
Studying Coulomb correction at EIC and EicC
Ze-hao Sun🇨🇳 · Du-xin Zheng🇨🇳 · Jian Zhou🇨🇳 · Ya-jin Zhou🇨🇳
We study the gauge link contribution to the dipole type transverse momentum dependent distributions of coherent photons, which is conventionally referred to as the Coulomb correction. We further propose to search for the evidence of the Coulomb correction in the Bethe-Heitler process in eA collisions at EIC and EicC.
hep-phPLB(2020)·20 citations
06*
Decay and electromagnetic production of strongly coupled quarkonia in pNRQCD
Nora Brambilla🇩🇪 · Hee Sok Chung🇩🇪 · Daniel Müller🇩🇪 · Antonio Vairo🇩🇪
We improve the pNRQCD approach to annihilation processes of heavy quarkonium and make first pNRQCD predictions for exclusive electromagnetic production of heavy quarkonium. We consider strongly coupled quarkonia, i.e., quarkonia that are not Coulombic bound states. Possible strongly coupled quarkonia include excited charmonium and bottomonium states. For these, pNRQCD provides expressions for the decay and exclusive electromagnetic production NRQCD matrix elements that depend on the wavefunctions at the origin and few universal gluon field correlators. We compute electromagnetic decay widths and exclusive production cross sections, and inclusive decay widths into light hadrons for $P$ -wave quarkonia at relative order $v^{2}$ and leading order, respectively. We also compute the decay widths of $2 S$ and $3 S$ bottomonium states into lepton pairs and their ratios with the inclusive widths into light hadrons at relative order $v^{2}$ .
hep-phJHEP(2020)·31 citations
07*
Implication of the hidden sub-GeV bosons for the $(g - 2)_{μ}$ , $^{8}$ Be- $^{4}$ He anomaly, proton charge radius, EDM of fermions and dark axion portal
D. V. Kirpichnikov🇷🇺 · Valery E. Lyubovitskij🇩🇪 · Alexey S. Zhevlakov🇷🇺
We discuss new physics phenomenology of hidden scalar ( $S$ ), pseudoscalar ( $P$ ), vector ( $V$ ) and axial-vector ( $A$ ) particles coupled to nucleons and leptons, which could give contributions to proton charge radius, $(g - 2)_{μ}$ , $^{8}$ Be- $^{4}$ He anomaly and electric dipole moment (EDM) of Standard Model (SM) particles. In particular, we estimate sensitivity of NA64 $μ$ experiment to observe muon missing energy events involving hidden scalar and vector particles. That analysis is based on {\tt GEANT4} Monte Carlo simulation of the signal process of muon scattering off target nuclei $μ N \to μ N S (V)$ followed by invisible boson decay into Dark Matter (DM) particles, $S (V) \to χχ$ . The existence of light sub-GeV bosons could possibly explain the muon $(g - 2)$ anomaly observed. We also summarize existing bounds on ATOMKI $X 17 (J^{P} = 0^{-}, 1^{\pm})$ boson coupling with neutron, proton and electron. We implement these constraints to estimate the contribution of $P$ , $V$ and $A$ particles to proton charge radius via direct 1-loop calculation of Sachs form factors. The analysis reveals the corresponding contribution is negligible. We also calculate bounds on dark axion portal couplings of dimension-five operators, which contribute to the EDMs of leptons and neutron.
hep-phPRD(2020)·45 citations
08*
QCD phase structure from functional methods
Fei Gao🇩🇪 · Jan M. Pawlowski🇩🇪
We discuss the QCD phase structure at finite temperature and chemical potential for $2$ -flavour and $2 + 1$ -flavour QCD. The results are achieved by computing QCD correlation functions within a generalised functional approach that combines Dyson-Schwinger equations (DSE) and the functional renormalisation group (fRG). In this setup fRG precision data from arXiv:1706.06326 for the vacuum quark-gluon vertex and gluon propagator of $2$ -flavour QCD are used as input, and the respective DSEs are expanded about this input. While the vacuum results for other correlation functions serve as a self-consistency check for functional approaches, the results at finite temperature and density are computed, for the first time, without the need of phenomenological infrared parameters.
hep-phhep-exhep-latnucl-thPRD(2020)·187 citations
09*
The quirk trajectory
Jinmian Li🇨🇳 · Tianjun Li🇨🇳 · Junle Pei🇨🇳 · Wenxing Zhang🇨🇳
We for the first time obtain the analytical solution for the quirk equation of motion in an approximate way. Based on it, we study several features of quirk trajectory in a more precise way, including quirk oscillation amplitude, number of periods, as well as the thickness of quirk pair plane. Moreover, we find an exceptional case where the quirk crosses at least one of the tracking layers repeatedly. Finally, we consider the effects of ionization energy loss and fixed direction of infracolor string for a few existing searches.
hep-phhep-exEPJC(2020)·14 citations
10*
Using neural networks for efficient evaluation of high multiplicity scattering amplitudes
Simon Badger🇬🇧 · Joseph Bullock🇬🇧
Precision theoretical predictions for high multiplicity scattering rely on the evaluation of increasingly complicated scattering amplitudes which come with an extremely high CPU cost. For state-of-the-art processes this can cause technical bottlenecks in the production of fully differential distributions. In this article we explore the possibility of using neural networks to approximate multi-variable scattering amplitudes and provide efficient inputs for Monte Carlo integration. We focus on QCD corrections to $e^{+} e^{-} \to$ jets up to one-loop and up to five jets. We demonstrate reliable interpolation when a series of networks are trained to amplitudes that have been divided into sectors defined by their infrared singularity structure. Complete simulations for one-loop distributions show speed improvements of at least an order of magnitude over a standard approach.
hep-phJHEP(2020)·72 citations
11*
Testing Yukawa Unification at LHC Run-3 and HL-LHC
Mario Gomez🇪🇸 · Qaisar Shafi🇺🇸 · Cem Salih Un🇹🇷
We explore $t - b - τ$ Yukawa unification (YU) in a supersymmetric $S U (4)_{c} \times S U (2)_{L} \times S U (2)_{R}$ model without imposing a discrete left-right (L-R) symmetry. A number of interesting solutions that are compatible with $t - b - τ$ YU, LSP neutralino dark matter (DM), and LHC and other experimental constraints are identified. In particular, they include gluino-neutralino and stau-neutralino co-annihilation scenarios, where the NLSP gluino mass can range from 1-3 TeV. Higgsino-like dark matter solutions are also identified for which gluino masses can approach 5 TeV or so. This scenario will be tested at LHC Run-3 and its future upgrades.
hep-phJHEP(2020)·18 citations
12*
Transverse momentum dependent factorization for lattice observables
Alexey A. Vladimirov🇩🇪 · Andreas Schäfer🇩🇪
Using soft collinear effective field theory, we derive the factorization theorem for the quasi-transverse-momentum-dependent (quasi-TMD) operator. We check the factorization theorem at one-loop level and compute the corresponding coefficient function and anomalous dimensions. The factorized expression is built from the physical TMD distribution, and a nonperturbative lattice related factor. We demonstrate that lattice related functions cancel in appropriately constructed ratios. These ratios could be used to explore various properties of TMD distributions, for instance, the nonperturbative evolution kernel. A discussion of such ratios and the related continuum properties of TMDs is presented.
hep-phhep-latPRD(2020)·63 citations
13*
Preserving unitarity for overlapping multichannel states: Breit-Wigner versus K matrix -- comparison, advantages and disadvantages
Victor Henner🇷🇺 · Tatyana Belozerova🇷🇺
The K-matrix method is often used to describe overlapping resonances. It guarantees the unitarity of the scattering matrix but its parameters are not resonances masses and widths. It is also unclear how to separate resonant and background contributions and to describe background in terms of phase shifts. The Breit-Wigner (BW) approach operates with parameters having direct experimental meaning but a simple sum of the BW functions is not unitary. We show how to construct the unitary S-matrix by taking into account the interference of the BW functions. The method is simple and straightforward, background can be added to resonance amplitudes in the standard quantum mechanics form. In examples we give a comparison between the K-matrix and unitary BW-approaches.
hep-ph1 citation
14*
String monopoles, string walls, vortex-skyrmions and nexus objects in polar distorted B-phase of $^{3}$ He
G. E. Volovik🇫🇮 · K. Zhang🇫🇮
The composite cosmological objects -- Kibble-Lazarides-Shafi (KLS) walls bounded by strings and cosmic strings terminated by Nambu monopoles -- could be produced during the phase transitions in the early Universe. Recent experiments in superfluid $^{3}$ He reproduced the formation of the KLS domain walls, which opened the new arena for the detailed study of those objects in human controlled system with different characteristic lengths. These composite defects are formed by two successive symmetry breaking phase transitions. In the first transition the strings are formed, then in the second transition the string becomes the termination line of the KLS wall. In the same manner, in the first transition monopoles are formed, and then in the second transition these monopoles become the termination points of strings. Here we show that in the vicinity of the second transition the composite defects can be described by relative homotopy groups. This is because there are two well separated length scales involved, which give rise to two different classes of the degenerate vacuum states, $R_{1}$ and $R_{2}$ , and the composite objects correspond to the nontrivial elements of the group $π_{n} (R_{1}, R_{2})$ . We discuss this on example of the so-called polar distorted B phase, which is formed in the two-step phase transition in liquid $^{3}$ He distorted by aerogel. In this system the string monopoles terminate spin vortices with even winding number, while KLS string walls terminate on half quantum vortices. In the presence of magnetic field, vortex-skyrmions are formed, and the string monopole transforms to the nexus. We also discuss the integer-valued topological invariants of those objects. Our consideration can be applied to the composite defects in other condensed matter and cosmological systems.
hep-phcond-mat.dis-nncond-mat.mes-hallcond-mat.supr-conPRResearch(2020)·25 citations
15*
Signatures of the two $K_{1} (1270)$ poles in $D^{+} \to ν e^{+} V P$ decay
Guan-Ying Wang🇨🇳 · Luis Roca🇪🇸 · En Wang🇨🇳 · Wei-Hong Liang🇨🇳 · Eulogio Oset🇪🇸
We analyze theoretically the $D^{+} \to ν e^{+} ρ K ˉ$ and $D^{+} \to ν e^{+} K ˉ^{*} π$ decays to see the feasibility to check the double pole nature of the axial-vector resonance $K_{1} (1270)$ predicted by the unitary extensions of chiral perturbation theory (UChPT). Indeed, within UChPT the $K_{1} (1270)$ is dynamically generated from the interaction of a vector and a pseudoscalar meson, and two poles are obtained for the quantum numbers of this resonance. The lower mass pole couples dominantly to $K^{*} π$ and the higher mass pole to $ρ K$ , therefore we can expect that different reactions weighing differently these channels in the production mechanisms enhance one or the other pole. We show that the different final $V P$ channels in $D^{+} \to ν e^{+} V P$ weigh differently both poles, and this is reflected in the shape of the final vector-pseudoscalar invariant mass distributions. Therefore, we conclude that these decays are suitable to distinguish experimentally the predicted double pole of the $K_{1} (1270)$ resonance.
hep-phEPJC(2020)·14 citations
16*
Multiphoton signals of a (96 GeV?) stealth boson
J.A. Aguilar-Saavedra🇪🇸 · F.R. Joaquim🇵🇹
Cascade decays of new scalars into final states with multiple photons and possibly quarks may lead to distinctive experimental signatures at high-energy colliders. Such signals are even more striking if the scalars are highly boosted, as when produced from the decay of a much heavier resonance. We study this type of events within the framework of the minimal stealth boson model, an anomaly-free $U (1)_{Y^{'}}$ extension of the Standard Model with two complex scalar singlets. It is shown that, while those signals may have cross sections that might render them observable with LHC Run 2 data, they have little experimental coverage. We also establish a connection with a CMS excess observed in searches for new scalars decaying into diphoton final states near 96 GeV. In particular, we conclude that the predicted multiphoton signatures are compatible with such excess.
hep-phhep-exEPJC(2020)·42 citations
17*
Manifestation of kaonium in the $e^{+} e^{-} \to K^{+} K^{-}$ process
P. Lichard🇨🇿
We analyze the precise data obtained by the CMD-3 experiment on the $e^{+} e^{-}$ annihilation into two charged kaons in the vicinity of the $ϕ$ peak. A perfect fit is obtained only if a pole on the real axis below the reaction threshold is assumed. This can be interpreted as proof of the existence of the 2p state of kaonium, a compound of $K^{+}$ and $K^{-}$ . The BaBar Collaboration data on the same process supports this conclusion and, in addition, points to the strong interaction as a dominant source of the binding energy. The possibility of discovering 2p kaonium in the $e^{+} e^{-} \to π^{+} π^{-}$ process is discussed. The 2p state of $K^{0}$ -onium is indicated on the basis of the CMD-3 $e^{+} e^{-} \to K_{S}^{0} K_{L}^{0}$ data.
hep-phhep-exnucl-thPRD(2020)·5 citations
18*
Direct comparison of sterile neutrino constraints from cosmological data, $ν_{e}$ disappearance data and $ν_{μ} \to ν_{e}$ appearance data in a $3 + 1$ model
Matthew Adams🇬🇧 · Fedor Bezrukov🇬🇧 · Jack Elvin-Poole🇺🇸 · Justin J. Evans🇬🇧 · Pawel Guzowski🇬🇧 · Brían Ó Fearraigh🇳🇱 · Stefan Söldner-Rembold🇬🇧
We present a quantitative, direct comparison of constraints on sterile neutrinos derived from neutrino oscillation experiments and from Planck data, interpreted assuming standard cosmological evolution. We extend a $1 + 1$ model, which is used to compare exclusions contours at the 95% CL derived from Planck data to those from $ν_{e}$ -disappearance measurements, to a $3 + 1$ model. This allows us to compare the Planck constraints with those obtained through $ν_{μ} \to ν_{e}$ appearance searches, which are sensitive to more than one active-sterile mixing angle. We find that the cosmological data fully exclude the allowed regions published by the LSND, MiniBooNE and Neutrino-4 collaborations, and those from the gallium and rector anomalies, at the 95% CL. Compared to the exclusion regions from the Daya Bay $ν_{e}$ -disappearance search, the Planck data are more strongly excluding above $∣Δ m_{41}^{2} ∣ \approx 0.1 eV^{2}$ and $m_{eff}^{sterile} \approx 0.2 eV$ , with the Daya Bay exclusion being stronger below these values. Compared to the combined Daya Bay/Bugey/MINOS exclusion region on $ν_{μ} \to ν_{e}$ appearance, the Planck data is more strongly excluding above $Δ m_{41}^{2} \approx 5 \times 1 0^{- 2} eV^{2}$ , with the exclusion strengths of the Planck data and the Daya Bay/Bugey/MINOS combination becoming comparable below this value.
hep-phastro-ph.COhep-exEPJC(2020)·22 citations
19*
Two-Loop QCD-EW Master Integrals for Z Plus Jet Production at Large Transverse Momentum
Hjalte Frellesvig🇩🇪 · Kirill Kudashkin🇩🇪 · Christopher Wever🇩🇪
The production of electroweak $Z$ bosons that decay to neutrinos and recoil against jets with large transverse momentum $p_{⊥}$ is an important background process to searches for dark matter at the Large Hadron Collider (LHC). To fully benefit from opportunities offered by the future high-luminosity LHC, the theoretical description of the $pp \to Z + j$ process should be extended to include mixed QCD-electroweak corrections. The goal of this paper is to initiate the computation of such corrections starting with the calculation of the Feynman integrals needed to describe two-loop QCD-electroweak contributions to $q q ˉ \to Z + g$ scattering amplitudes. Making use of the hierarchy between the large transverse momenta of the recoiling jet, relevant for heavy dark matter searches, and the $Z$ boson mass $m_{Z}$ , we present the relevant master integrals as a series expansion in $m_{Z} / p_{⊥}$ .
hep-phJHEP(2020)·4 citations
20*
GLIMPSE: Graphene-based super-Light Invisible Matter Particle SEarch
Doojin Kim🇺🇸 · Jong-Chul Park🇰🇷 · Gil-Ho Lee🇰🇷 · Kin Chung Fong🇺🇸
We propose a new dark-matter detection strategy that will potentially enable the search for super-light dark matter $m_{χ} ≃ 0.1$ keV, improving the minimum detectable mass by more than three orders of magnitude compared to ongoing experiments. This can be achieved by intimately integrating the target material, specifically the $π$ -bond electrons in graphene, into a Josephson junction to create a highly sensitive detector capable of detecting energy deposits from dark matter as small as $\sim 0.1$ meV. We investigate detection prospects of pg-, ng-, and $μ$ g-scale detectors by calculating the scattering rate between dark matter and free electrons confined in two-dimensional graphene, including Pauli-blocking factors and in-medium screening effects. We find that the proposed detector is expected to not only serve as a complementary probe of super-light dark matter but also achieve higher experimental sensitivities than other proposed experiments, assuming zero readout noise, thanks to the extremely low threshold energy of our graphene Josephson junction sensor.
hep-phcond-mat.mes-hallhep-exPRD(2025)·18 citations
21*
Power meets Precision to explore the Symmetric Higgs Portal
Christoph Englert🇬🇧 · Joerg Jaeckel🇩🇪 · Michael Spannowsky🇬🇧 · Panagiotis Stylianou🇬🇧
We perform a comprehensive study of collider aspects of a Higgs portal scenario that is protected by an unbroken $Z_{2}$ symmetry. If the mass of the Higgs portal scalar is larger than half the Higgs mass, this scenario becomes very difficult to detect. We provide a detailed investigation of the model's parameter space based on analyses of the direct collider sensitivity at the LHC as well as at future lepton and hadron collider concepts and analyse the importance of these searches for this scenario in the context of expected precision Higgs and electroweak measurements. In particular we also consider the associated electroweak oblique corrections that we obtain in a first dedicated two-loop calculation for comparisons with the potential of, e.g., GigaZ. The currently available collider projections corroborate an FCC-hh 100 TeV as a very sensitive tool to search for such a weakly-coupled Higgs sector extension, driven by small statistical uncertainties over a large range of energy coverage. Crucially, however, this requires good theoretical control. Alternatively, Higgs signal-strength measurements at an optimal FCC-ee sensitivity level could yield comparable constraints.
hep-phhep-exPLB(2020)·22 citations
22*
Neutrino decoherence in an electron and nucleon background
José F. Nieves🇺🇸 · Sarira Sahu🇲🇽
We consider the decoherence effects in the propagation of active neutrinos due to the non-forward neutrino scattering processes in a matter background composed of electrons and nucleons. We calculate the contribution to the imaginary part of the neutrino self-energy arising from such processes. Since the initial neutrino state is depleted but does not actually disappear (the initial neutrino transitions into a neutrino of a different flavor but does not decay) those processes should be associated with decoherence effects that cannot be described in terms of the coherent evolution of the state vector. Based on the formalism developed in our previous work for treating the non-forward scattering processes using the notion of the stochastic evolution of the state, we identify the jump operators, as used in the context of the master or Lindblad equation, in terms of the results of the the calculation of the non-forward neutrino scattering contribution to the imaginary part of the neutrino self-energy. As a guide to estimating the decoherence effects in situations of practical interest we give explicit formulas for the decoherence terms for different background conditions, and point out some of the salient features in particular the neutrino energy dependence. To establish contact wih previous works in which the decoherence terms are treated as phenomenological parameters, we consider the solution to the evolution equation in the two-generation case. We give formulas that are useful for estimating the effects of the decoherence terms under various conditions and environments, including the typical conditions applicable to long baseline experiments, where matter effects are important. In those contexts the effects appear to be small, and indicative that if significant decoherence effects were to be found they would be due to non-standard contributions to the decoherence terms.
hep-phPRD(2020)·16 citations
23*
Sub-Planckian $ϕ^{2}$ Inflation in the Palatini Formulation of Gravity with an $R^{2}$ term
Amy Lloyd-Stubbs🇬🇧 · John McDonald🇬🇧
In the context of the Palatini formalism of gravity with an $R^{2}$ term, a $ϕ^{2}$ potential can be consistent with the observed bound on $r$ whilst retaining the successful prediction for $n_{s}$ . Here we show that the Palatini $ϕ^{2} R^{2}$ inflation model can also solve the super-Planckian inflaton problem of $ϕ^{2}$ chaotic inflation, and that the model can be consistent with Planck scale-suppressed potential corrections. If $α ≳ 1 0^{12}$ , where $α$ is the coefficient of the $R^{2}$ term, the inflaton in the Einstein frame, $σ$ , remains sub-Planckian throughout inflation. In addition, if $α ≳ 1 0^{20}$ then the predictions of the model are unaffected by Planck-suppressed potential corrections in the case where there is a broken shift symmetry, and if $α ≳ 1 0^{32}$ then the predictions are unaffected by Planck-suppressed potential corrections in general. The value of $r$ is generally small, with $r ≲ 1 0^{- 5}$ for $α ≳ 1 0^{12}$ . We calculate the maximum possible reheating temperature, $T_{R ma x}$ , corresponding to instantaneous reheating. For $α \approx 1 0^{32}$ , $T_{R ma x}$ is approximately $1 0^{10}$ GeV, with larger values of $T_{R ma x}$ for smaller $α$ . For the case of instantaneous reheating, we show that $n_{s}$ is in agreement with the 2018 Planck results to within 1- $σ$ , with the exception of the $α \approx 1 0^{32}$ case, which is close to the 2- $σ$ lower bound. Following inflation, the inflaton condensate is likely to rapidly fragment and form oscillons. Reheating via inflaton decays to right-handed neutrinos can easily result in instantaneous reheating. We determine the scale of unitarity violation and show that, in general, unitarity is conserved during inflation.
hep-phastro-ph.COgr-qchep-thPRD(2020)·41 citations
24*
Strings of diquark-quark (QQ)Q baryon before phase transition
A.S. Bakry🇨🇳 · M.A. Deliyergiyev🇨🇭 · A.A. Galal🇪🇬 · M.N. Khalil🇩🇪
We explore the limit at which the effective baryonic Y-string model of the junction approaches the mesonic stringlike behavior. We calculate and compare the numerical values of the static potential and energy-density correlators of diquark-quark and quark-antiquark configurations. The gauge model is pure Yang-Mills $S U (3)$ lattice gauge theory at coupling $β = 6.0$ and finite temperature. The diquark setup is approximated as two quarks confined within a sphere of radius $0.1$ fm. The lattice data of the potential and energy show that the string binding the diquark-quark configuration displays an identical behavior to the quark-antiquark confining string. However, with the temperature increase to a small enough neighborhood of the critical point $T_{c}$ , the gluonic similarities between the two systems do not manifest neither at short nor intermediate distance scales $R < 1.0$ fm. The comparison between the potential and the second moment of the action-density correlators for both systems shows significant splitting. This suggests that subsisted baryonic decoupled states overlap with the mesonic spectrum. The baryonic junction's model for the potential and the profile returns a good fit to the numerical lattice data of the diquark-quark arrangement. However, near the critical point, the mesonic string displays large deviations compared to fits of the corresponding quark-antiquark data.
↳ hep-lathep-phnucl-thPRD(2023)·3 citations
25*
Parity non-conservation in a condensed matter system
Veit Elser🇺🇸
The nuclear spin of a He $^{3}$ quasiparticle dissolved in superfluid He $^{4}$ sees an apparent magnetic field proportional to the Fermi coupling constant, the superfluid condensate density, and the electron current at the He $^{3}$ nucleus. Whereas the direction of the current must be parallel to the quasiparticle momentum, calculating its magnitude presents an interesting theoretical challenge because it vanishes in the Born-Oppenheimer approximation. We find the effect is too small to be observed and present our results in the hope others will be inspired to look for similar effects in other systems.
↳ cond-mat.otherhep-phphysics.atom-ph0 citations
26*
Can we overcome the neutrino floor at high masses?
Ciaran A. J. O'Hare🇦🇺
The neutrino floor is a barrier in the parameter space of weakly interacting massive particles (WIMPs) below which discovery is impeded due to an almost irreducible background of neutrinos. Directional gas time projection chambers could discriminate against solar neutrinos, relevant for WIMP masses $≲$ 10 GeV. At higher masses $≳$ 100 GeV the floor is set by the background of atmospheric neutrinos. Probing below this part of the floor would require very large target exposures. Since gas-based detectors would be prohibitively large at this scale, we instead reevaluate the prospects for liquid noble experiments to probe below the neutrino floor. We combine all potential methods of subtracting the neutrino background to determine how much of this difficult to reach, but well-motivated, parameter space it is feasible to reach. Most notably, we quantify whether a proposed directional signal in xenon and argon experiments called "columnar recombination" can help in this task. We find that even if the strength of this effect is amplified beyond current experimental results, the quantity of directional information contained in the recombination signal is too low to realistically discriminate against the atmospheric neutrino background. Instead, benefiting from the refined measurements of neutrino fluxes by experiments such as DUNE and JUNO will be the most practical means to push direct WIMP searches below the neutrino floor. For an ultimate global coordination of xenon and argon experiments, we show that the neutrino floor is a surmountable barrier. The direct detection of 100 GeV-scale supersymmetric WIMPs may, eventually, be within reach.
↳ astro-ph.COhep-exhep-phPRD(2020)·75 citations
27*
Gravitational Waves from Primordial Magnetic Fields via Photon-Graviton Conversion
Tomohiro Fujita🇯🇵 · Kohei Kamada🇯🇵 · Yuichiro Nakai🇨🇳
We explore a novel process in the early Universe in which thermalized photons are converted into gravitons in the presence of strong primordial magnetic fields. It is found that the frequency of generated gravitational waves (GWs) is typically of order of GHz and their amplitude can be up to $Ω_{GW} h^{2} \sim 1 0^{- 10}$ . If detected with future developments of the technology to explore this frequency region, the produced stochastic GW background enables us to know when and how strong the primordial magnetic fields are generated. From the peak frequency of the GWs, we can also probe the number of relativistic degrees of freedom at that time.
↳ astro-ph.COgr-qchep-phPRD(2020)·42 citations
28*
Vorticity and Spin Polarization --- A Theoretical Perspective
Xu-Guang Huang🇨🇳
We give a theoretical perspective on the vorticity and spin polarization in heavy-ion collisions. We discuss the recent progress in spin hydrodynamics and spin kinetic theory. We also discuss other effects caused by vorticity including the chiral vortical effect and rotation-induced phase transitions.
↳ nucl-thhep-phnucl-exNPA(2021)·50 citations
29*
The implications of the axion like particle from the Fermi-LAT and H.E.S.S. observations of PG 1553+113 and PKS 2155-304
Junguang Guo🇨🇳 · Hai-Jun Li🇨🇳 · Xiao-Jun Bi🇨🇳 · Su-Jie Lin🇨🇳 · Peng-Fei Yin🇨🇳
We investigate the axion like particle (ALP)-photon oscillation effect in the high energy $γ$ -ray spectra of PG 1553+113 and PKS 2155-304 measured by Fermi-LAT and H.E.S.S.. The choice of extragalactic background light (EBL) model, which induces the attenuate effect in observed $γ$ -ray spectra, would affect the ALP implication. For the ordinary EBL model that prefers a null hypothesis, we set constraint on the ALP-photon coupling constant at 95% C.L. as $g_{aγ} ≲ 5 \times 1 0^{- 11} GeV^{- 1}$ for the ALP mass $\sim 10$ neV. We also consider the CIBER observation of the cosmic infrared radiation, which shows an excess at the wave wavelength of $\sim 1 μ$ m after the substraction of foregrounds. The high energy gamma-rays from extragalactic sources at high redshifts would suffer from a more significant attenuate effect caused by this excess. In this case, we find that the ALP-photon oscillation would improve the fit to the observed spectra of PKS 2155-304 and PG 1553+113 and find a favored parameter region at 95% C.L..
↳ astro-ph.HEhep-phCPC(2021)·37 citations
30*
Scalable haloscopes for axion dark matter detection in the 30 $μ$ eV range with RADES
A. Álvarez Melcón🇪🇸 · S. Arguedas Cuendis🇨🇭 · C. Cogollos🇪🇸 · A. Díaz-Morcillo🇪🇸 · B. Döbrich🇨🇭 · J.D. Gallego🇪🇸 · J.M. García Barceló🇪🇸 · B. Gimeno🇪🇸 · J. Golm🇩🇪 · I.G. Irastorza🇪🇸 · A.J. Lozano-Guerrero🇪🇸 · C. Malbrunot🇨🇭 and 5 other authors
RADES (Relic Axion Detector Exploratory Setup) is a project with the goal of directly searching for axion dark matter above the $30 μ$ eV scale employing custom-made microwave filters in magnetic dipole fields. Currently RADES is taking data at the LHC dipole of the CAST experiment. In the long term, the RADES cavities are envisioned to take data in the (baby)-IAXO magnet. In this article we report on the modelling, building and characterisation of an optimised microwave-filter design with alternating irises that exploits maximal coupling to axions while being scalable in length without suffering from mode-mixing. We develop the mathematical formalism and theoretical study which justifies the performance of the chosen design. We also point towards the applicability of this formalism to optimise the MADMAX dielectric haloscopes.
↳ hep-exhep-phJHEP(2020)·53 citations
31*
Effective field theory interactions for liquid argon target in DarkSide-50 experiment
The DarkSide-50 Collaboration: P. Agnes🇺🇸 · I. F. M. Albuquerque🇧🇷 · T. Alexander🇺🇸 · A. K. Alton🇺🇸 · M. Ave🇧🇷 · H. O. Back🇺🇸 · G. Batignani🇮🇹 · K. Biery🇺🇸 · V. Bocci🇮🇹 · G. Bonfini🇮🇹 · W. M. Bonivento🇮🇹 · B. Bottino🇮🇹 and 154 other authors
We reanalize data collected with the DarkSide-50 experiment and recently used to set limits on the spin-independent interaction rate of weakly interacting massive particles (WIMPs) on argon nuclei with an effective field theory framework. The dataset corresponds to a total (16660 $\pm$ 270) kg d exposure using a target of low-radioactivity argon extracted from underground sources. We obtain upper limits on the effective couplings of the 12 leading operators in the nonrelativistic systematic expansion. For each effective coupling we set constraints on WIMP-nucleon cross sections, setting upper limits between $2.4 \times 1 0^{- 45} cm^{2}$ and $2.3 \times 1 0^{- 42} cm^{2}$ (8.9 $\times 1 0^{- 45} cm^{2}$ and 6.0 $\times 1 0^{- 42} cm^{2}$ ) for WIMPs of mass of 100 $GeV/ c^{2}$ (1000 $GeV/ c^{2}$ ) at 90\% confidence level.
↳ hep-exhep-phphysics.ins-detPRD(2020)·17 citations
32*
Ruling Out the Massless Up-Quark Solution to the Strong CP Problem by Computing the Topological Mass Contribution with Lattice QCD
Constantia Alexandrou🇨🇾 · Jacob Finkenrath🇨🇾 · Lena Funcke🇨🇦 · Karl Jansen🇩🇪 · Bartosz Kostrzewa🇩🇪 · Ferenc Pittler🇩🇪 · Carsten Urbach🇩🇪
The infamous strong CP problem in particle physics can in principle be solved by a massless up quark. In particular, it was hypothesized that topological effects could substantially contribute to the observed nonzero up-quark mass without reintroducing CP violation. Alternatively to previous work using fits to chiral perturbation theory, in this Letter, we bound the strength of the topological mass contribution with direct lattice QCD simulations, by computing the dependence of the pion mass on the dynamical strange-quark mass. We find that the size of the topological mass contribution is inconsistent with the massless up-quark solution to the strong CP problem.
↳ hep-lathep-phhep-thPRL(2020)·54 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.