HEP Phenomenology·hep-ph

Tue·Sep 17, 2019Tuesday·September 17, 2019

32 papers—19 primary·13 cross-listed·reconstructed*

01*
Modular $A_{4}$ invariance and leptogenesis
Takehiko Asaka🇯🇵 · Yongtae Heo🇯🇵 · Takuya H. Tatsuishi🇯🇵 · Takahiro Yoshida🇯🇵
We consider a model with three right-handed neutrinos in which Yukawa coupling constants and Majorana masses are obtained by requiring the modular $A_{4}$ symmetry. It has been shown that the model can explain mass hierarchies and mixing patterns of charged leptons and neutrinos with the seesaw mechanism. In this article we investigate the leptogenesis by decays of right-handed neutrinos in this model. It is shown that masses of right-handed neutrinos are about $1 0^{13}$ GeV in order to account for the observed baryon asymmetry of the universe. Furthermore, the positive sign of the baryon asymmetry is obtained only for the limited ranges of mixing angles and CP violation phases of active neutrinos, which can be tested by future neutrino experiments.
hep-phastro-ph.COJHEP(2020)·121 citations
02*
The influence of the scalar unparticle on the W-pair production at ILC in the Randall Sundrum model
Dang Van Soa🇻🇳 · Bui Thi Ha Giang🇻🇳
An attempt is made to present the contribution of the scalar unparticle on some scattering processes in the Randall - Sundum (RS) model. We have evaluated the contribution of the scalar unparticle on the W - pair production cross-sections at International Linear Colliders (ILC). The results indicate that at the low values of the scaling dimension and the bounds on scale $Λ_{U}$ are around few TeV, the cross-sections are much enhanced, which is quite comparable with the W-production in the standard model and hence it is worthwhile to explore in future colliders.
hep-phMod.Phys.Lett.A(2020)·5 citations
03*
Divalent lanthanoid ions in crystals for neutrino mass spectroscopy
H. Hara🇯🇵 · N. Sasao🇯🇵 · M. Yoshimura🇯🇵
Electron spin flip in atoms or ions can cause neutrino pair emission, which provides a method to explore still unknown important neutrino properties by measuring spectrum of emitted photon in association, when electroweak rates are amplified by a phase coherence among participating atoms. Two important remaining neutrino issues to be determined are the absolute neutrino mass (or the smallest neutrino mass in the three-flavor scheme) and the nature of neutrino masses, either of Dirac type or of Majorana type. Use of Raman scattered photon was recently proposed as a promising tool for this purpose. In the present work we continue along this line to further identify promising ion targets in crystals, calculate neutrino pair emission rates, and study how to extract neutrino properties from Raman scattered photon angular distribution. Divalent lanthanoid ions in crystals, in particular Sm $^{2 +}$ , are the most promising, due to (1) its large number density, (2) sharp optical lines, (3) a variety of available ionic levels. Rejection of amplified quantum electrodynamic backgrounds is made possible to controllable levels by choosing a range of Raman trigger direction, when Sm $^{2 +}$ sites are at O $_{h}$ inversion center of host crystals such as SrF $_{2}$ .
hep-phcond-mat.mtrl-scihep-exphysics.atom-ph2 citations
04*
Reply to E. Shuryak's Comments on "Three regimes of QCD"
L. Ya. Glozman🇦🇹
In his recent Comments E. Shuryak reiterates old, unfortunately misleading arguments in favor of deconfined Quark-Gluon Plasma (QGP) immediately above the chiral restoration pseudocritical temperature. In a Comment devoted to our view of QCD at high temperatures he does not address and even mention the essence of our arguments. In recent years a new "hidden" symmetry in QCD was discovered. It is a symmetry of the electric sector of QCD, that is higher than the chiral symmetry of the QCD Lagrangian as the whole. This symmetry was clearly observed above T_c in spatial correlators and very recently also in time correlators. The latter correlators are directly related to observable spectral density. Then in a model-independent way we conclude that degrees of freedom in QCD above T_c, but below roughly 3T_c, are chirally symmetric quarks bound by the chromoelectric field into color-singlet compounds without the chromomagnetic effects. This regime of QCD has been referred to as a Stringy Fluid since such objects are very reminiscent of strings.At higher temperatures there is a very smooth transition to the partonic degrees of freedom, i.e. to the QGP regime. Here we will address some of the points made by Shuryak.
hep-phhep-latnucl-th2 citations
05*
Higgs boson pair production via gluon fusion at N $^{3}$ LO in QCD
Long-Bin Chen🇨🇳 · Hai Tao Li🇺🇸 · Hua-Sheng Shao🇫🇷 · Jian Wang🇨🇳
We present next-to-next-to-next-to-leading order (N $^{3}$ LO) QCD predictions for the Higgs boson pair production via gluon fusion at hadron colliders in the infinite top-quark mass limit. Besides the inclusive total cross sections at various collision energies, we also provide the invariant mass distribution of the Higgs boson pair. Our results show that the N $^{3}$ LO QCD corrections enhance the next-to-next-to-leading order cross section by $3.0%$ ( $2.7%$ ) at $s = 13 (100)$ TeV, while the scale uncertainty is reduced substantially below $3%$ ( $2%$ ). We also find that a judicious scale choice can significantly improve the perturbative convergence. For the invariant mass distribution, our calculation demonstrates that the N $^{3}$ LO corrections improve the scale dependence but almost do not change the shape.
hep-phhep-exPLB(2020)·132 citations
06*
Parameter space stability of multiple soft interactions
Rahul Kumar Thakur🇮🇳 · Bhupendra Nath Tiwari🇮🇹 · Rahul Nigam🇮🇳
We study the fluctuation theory analysis of multiple soft interactions that are used to design SIBYLL 2.1 and related cosmic ray event generators. We examine fluctuation stabilities of Lund string fragmentation involving quark-antiquark and diquark-antidiquark pairs. Using the primordial transverse momentum hadron-hadron pairs, we find that the resulting Gaussian distribution yields an ill-defined ensemble under fluctuation of the model parameters of parent quark and diquarks. Further, we investigate the nature of multiple soft interactions through Pomeron-Reggeon fluctuations at various energy scales. We show that there are both stable and unstable regions under fluctuations of the Reggeon and Pomeron densities and all initial energy scales. The optimal stability zone is achieved at the Reggeon and Pomeron densities as predicted by GRV model. For hadron-hadron collisions, the limiting Gaussian profile as a function of the impact parameters of soft interactions for proton-proton collisions corresponds to an indeterminate statistical basis. Subsequently, we add higher order corrections in the Regge trajectory of constituent hadrons that play an important role in determining the shape of a proton or meson profile function in the realm of minijet model. We also discuss the accelerated nucleons with jerks and soft profile functions at off-shell-conditions. In addition, we illustrate the wall of stability/instability for multiple soft interactions by considering energy dependent soft contributions to scattering cross section as the model embedding. Qualitative discussions are provided at physical energy scales ranging from 1 GeV to 1800 GeV. This includes the analysis of CDF, P238, UA5 and ZEUS experiments.
hep-phNPA(2020)·0 citations
07*
IceCube PeV Neutrino Events from the Decay of Superheavy Dark Matter;an Analysis
Madhurima Pandey🇮🇳 · Debasish Majumdar🇮🇳 · Ashadul Halder🇮🇳
Considering the ultrahigh energy (UHE) neutrino events reported by IceCube in the PeV regime to have originated from the decay of superheavy dark matter, the IceCube UHE neutrino events are analysed and the best fit values of the two parameters namely the mass of the superheavy dark matter and its decay lifetime are obtained. The theoretical astrophysical flux is also included in theanalysis. We find that while the neutrino events in the energy range $\sim$ 60 TeV- $\sim$ 120 TeV appears to have astrophysical origin, the events in the energy range $\sim 1.2 \times 1 0^{5}$ GeV - $\sim 5 \times 1 0^{7}$ GeV can be well described from the superheavy dark matter decay hypothesis. We also find that although hadronic decay channel of the superheavy dark matter can well explain the events in the energy range $\sim 1.2 \times 1 0^{5}$ GeV - $\sim 5 \times 1 0^{6}$ GeV, the higher energy regime higher than this range can be addressed only when the leptonic decay channel is considered.
hep-phastro-ph.CO4 citations
08*
Millicharged particles at electron colliders
Jinhan Liang🇨🇳 · Zuowei Liu🇨🇳 · Yue Ma🇨🇳 · Yu Zhang🇨🇳
We propose to search for millicharged particles in electron colliders operated with the center-of-mass energies at $O$ (1-10) GeV, which include Belle II, BESIII, BaBar, and also the proposed experiment STCF. We use the monophoton final state at electron colliders to probe the parameter space of millicharged particles, that is spanned by millicharge $ϵ$ and mass $m$ . We find that electron colliders have sensitivity to the previously unexplored parameter space for millicharged particles with MeV-GeV mass: $ϵ ≲ O (1 0^{- 1})$ for $0.5$ GeV $≲ m ≲ 3.5$ GeV in BaBar, $ϵ ≲ O (1 0^{- 3})$ for $0.1$ GeV $≲ m ≲ 1.5$ GeV in BESIII, $ϵ ≲ 1 0^{- 3} - 1 0^{- 2}$ for $0.1$ GeV $≲ m ≲ 4$ GeV in Belle II, and $ϵ ≲ O (1 0^{- 4})$ for $1$ MeV $≲ m ≲ 1$ GeV in STCF.
hep-phastro-ph.COastro-ph.HEastro-ph.SRPRD(2020)·32 citations
09*
A note on the predictions of models with modular flavor symmetries
Mu-Chun Chen🇺🇸 · Saul Ramos-Sanchez🇲🇽 · Michael Ratz🇺🇸
Models with modular flavor symmetries have been thought to be highly predictive. We point out that these predictions are subject to corrections from non-holomorphic terms in the Lagrangean. Specifically, in the models discussed in the literature, the Kähler potential is not fixed by the symmetries, for instance. The most general Kähler potential consistent with the symmetries of the model contains additional terms with additional parameters, which reduce the predictive power of these constructions. We also comment on how one may conceivably retain the predictivity.
hep-phhep-thPLB(2020)·140 citations
10*
Equation of state and chiral transition in soft-wall AdS/QCD with more realistic gravitational background
Zhen Fang🇨🇳 · Yue-Liang Wu🇨🇳
We construct an improved soft-wall AdS/QCD model with a cubic coupling term of the dilaton and the bulk scalar field. The background fields in this model are solved from the Einstein-dilaton system with a nontrivial dilaton potential, which has been shown to be able to reproduce the equation of state from lattice QCD with two flavors. The chiral transition behaviors are investigated in the improved soft-wall AdS/QCD model with the solved gravitational background, and the crossover transition can be realized. Our study provides a possibility to address the deconfining and chiral phase transitions simultaneously in the bottom-up holographic framework.
hep-phCPC(2020)·12 citations
11*
Study of nuclear modification factors of (anti-)hadrons and light (anti-)nuclei in Pb-Pb collisions at $s_{NN}$ = 2.76 TeV
Zhi-Lei She🇨🇳 · Gang Chen🇨🇳 · Feng-Xian Liu🇨🇳 · Liang Zheng🇨🇳 · Yi-Long Xie🇨🇳
The nuclear modification factors ( $R_{AA}$ ) of $π^{\pm}, p (p ˉ)$ , and $d (d ˉ)$ with $∣ y ∣ < 0.5, p_{T} < 20.0$ ~GeV/c in peripheral (40-60\%) and central (0-5\%) Pb-Pb collisions at $s_{N N} = 2.76$ TeV have been studied using the parton and hadron cascade ({\footnotesize PACIAE}) model plus the dynamically constrained phase space coalescence ({\footnotesize DCPC}) model. It is found that the $R_{AA}$ of light (anti)nuclei ( $d, d ˉ$ ) is similar to that of hadrons ( $π^{\pm}, p, p ˉ$ ), and the $R_{AA}$ of antiparticles is the same as that of particles. The suppression of $R_{AA}$ at high- $p_{T}$ strongly depends on event centrality and mass of the particles, i.e., the central collision is more suppressed than the peripheral collision. Besides, the yield ratios and double ratios for different particle species in $pp$ and Pb-Pb collisions are discussed, respectively. It is observed that the yield ratios and double ratios of $d$ to $p$ and $p$ to $π$ are similar to those of their anti-particles in three different collision systems, suggesting that the suppressions of matter ( $π^{+}, p, d$ ) and the corresponding antimatter ( $π^{-}, p ˉ, d ˉ$ ) are around the same level.
hep-phnucl-th2 citations
12*
Dark matter and Collider signals in supersymmetric $U (1)^{'}$ models with non-universal $Z^{'}$ couplings
Mariana Frank🇨🇦 · Katri Huitu🇫🇮 · Subhadeep Mondal🇫🇮
We analyse supersymmetric models augmented by an extra $U (1)$ gauge group. To avoid anomalies in these models without introducing exotics, we allow for family-dependent $U (1)^{'}$ charges, and choose a simple form for these, dependent on one $U (1)^{'}$ charge parameter only. With this choice, $Z^{'}$ decays into di-taus but not di-leptons, weakening considerably the constraints on its mass. In the supersymmetric sector, the effect is to lower the singlino mass, allowing it to be the dark matter candidate. We investigate the dark matter constraints and collider implications of such models, with mostly singlino, or mostly higgsinos, or a mixture of the two as lightest supersymmetric particles. In these scenarios, $Z^{'}$ decays significantly into chargino or neutralino pairs, and thus indirectly into final state leptons. We devise benchmarks which, with adequate cuts, can yield signals visible at the high-luminosity LHC.
hep-phPRD(2019)·6 citations
13*
The Bridge Between Chiral Lagrangians and QCD Sum-Rules
Amir H. Fariborz🇺🇸 · J. Ho🇨🇦 · A. Pokraka🇨🇦 · T.G. Steele🇨🇦
Properties of the scale-factor matrices forming a bridge between the mesonic fields of chiral Lagrangians and quark-level structures of QCD sum-rules are reviewed. The scale-factor matrices combined with mixing angles provide a physical projection of a QCD correlation function matrix that disentangles the mesonic states. This methodology is illustrated for the isotriplet $a_{0} (980)$ - $a_{0} (1450)$ system, and the scale factors are determined from the combined inputs of QCD sum-rules and chiral Lagrangians. The resulting scale factors are shown to be in good agreement with the vacuum expectation values in the chiral Lagrangian framework. The sensitivity of the scale factors on the gluon condensate QCD sum-rule parameter is explored.
hep-phNucl.Part.Phys.Proc.(2020)·3 citations
14*
Triply charged Higgs bosons at a 100 TeV $pp$ collider
Junxing Pan🇨🇳 · Jung-Hsin Chen🇹🇼 · Xiao-Gang He🇹🇼 · Gang Li🇹🇼 · Jhih-Ying Su🇹🇼
The neutral Higgs boson predicted from spontaneous breaking of electroweak symmetry in the standard model (SM) has been discovered. Precision test of the Higgs boson properties is one of the promising ways to study new physics beyond SM. Some of the most important information to know is whether there are additional Higgs bosons, neutral, singly charged and even multi-charged ones. In this work, we study the potential to search for triply charged Higgs bosons in the final state with at least three same-sign leptons. A detailed collider analysis of the SM backgrounds and signals at a 100~TeV $pp$ collider is performed with $5 σ$ discovery prospects being obtained, which are expressed as a function of the vacuum expectation value (VEV) $v_{Δ}$ or the mass splitting $Δ m$ . We also revisit the sensitivity at the Large Hadron Collider (LHC) by projecting that at a 100~TeV $pp$ collider. For a comparison, two benchmark values $v_{Δ} = 1 0^{- 6} GeV$ and $5 \times 1 0^{- 3} GeV$ are taken. We find that for the triply charged Higgs boson mass below 1~TeV $5 σ$ discovery significance can be reached at a 100~TeV $pp$ collider with $3.3 fb^{- 1}$ and $110 fb^{- 1}$ of data, respectively, the sensitivity of which is much better than that at the LHC.
hep-phEPJC(2021)·7 citations
15*
Resonant $a_{0} (980)$ state in triangle rescattering $D_{s}^{+} \to π^{+} π^{0} η$ decays
Y.K. Hsiao🇨🇳 · Yao Yu🇨🇳 · Bai-Cian Ke🇨🇳
We study the $D_{s}^{+} \to π^{+} (a_{0} (980)^{0} \to) π^{0} η$ , $π^{0} (a_{0} (980)^{+} \to) π^{+} η$ decays, which have been recently measured by the BESIII collaboration. We propose that $D_{s}^{+} \to π^{+ (0)} (a_{0} (980)^{0 (+)} \to) π^{0 (+)} η$ receives the contributions from the triangle rescattering processes, where $M^{0}$ and $ρ^{+}$ in $D_{s}^{+} \to M^{0} ρ^{+}$ , by exchanging $π^{0 (+)}$ , are formed as $a_{0} (980)^{0 (+)}$ and $π^{+ (0)}$ , respectively, with $M^{0} = (η, η^{'})$ . Accordingly, we calculate that $B (D_{s}^{+} \to a_{0} (980)^{0 (+)} π^{+ (0)}) = (1.7 \pm 0.2 \pm 0.1) \times 1 0^{- 2}$ and $B (D_{s}^{+} \to π^{+ (0)} (a_{0} (980)^{0 (+)} \to) π^{0 (+)} η) = (1.4 \pm 0.1 \pm 0.1) \times 1 0^{- 2}$ , being consistent with the data.
hep-phhep-exEPJC(2020)·59 citations
16*
Superradiant Searches for Dark Photons in Two Stage Atomic Transitions
Amit Bhoonah🇨🇦 · Joseph Bramante🇨🇦 · Ningqiang Song🇨🇦
We study a new mechanism to discover dark photon fields, by resonantly triggering two photon transitions in cold gas preparations. Using coherently prepared cold parahydrogen, coupling sensitivity for sub-meV mass dark photon fields can be advanced by orders of magnitude, with a modified light-shining-through-wall setup. We calculate the effect of a background dark photon field on the dipole moment and corresponding transition rate of cold parahydrogen pumped into its first vibrational excited state by counter-propagating laser beams. The nonlinear amplification of two photon emission triggered by dark photons in a cold parahydrogen sample is numerically simulated to obtain the expected dark photon coupling sensitivity.
hep-phhep-exPRD(2020)·10 citations
17*
Discovering the $h \to Z γ$ Decay in $t t ˉ$ Associated Production
Florian Goertz🇩🇪 · Eric Madge🇩🇪 · Pedro Schwaller🇩🇪 · Valentin Titus Tenorth🇩🇪
We explore the prospects to discover the $h \to Z γ$ decay in $t t ˉ$ -associated production, featuring a signal-to-background ratio of $O (1)$ . Performing a detailed analysis of the semi-leptonic $t t ˉ$ -decay channel, we demonstrate that the production mode could lead to a $\sim 5 σ$ discovery at the high-luminosity LHC, while the effective $h Z γ$ coupling could be extracted with a $\sim 15 %$ accuracy. Extending the analysis to potential future $pp$ colliders with 27 TeV and 100 TeV center-of-mass energies, we also show that the latter would allow precision measurements at the few percent level, rendering possible precise extractions of the spin and CP properties of the Higgs boson.
hep-phhep-exPRD(2020)·5 citations
18*
Charged lepton flavour change and Non-Standard neutrino Interactions
Sacha Davidson🇫🇷 · Martin Gorbahn🇬🇧
Non-Standard neutrino Interactions (NSI) are vector contact interactions involving two neutrinos and two first generation fermions, which can affect neutrino propagation in matter. SU(2) gauge invariance suggests that NSI should be accompanied by more observable charged lepton contact interactions. However, these can be avoided at tree level in various ways. We focus on lepton flavour-changing NSI, suppose they are generated by New Physics heavier than $m_{W}$ that does not induce (charged) Lepton Flavour Violation (LFV) at tree level, and show that LFV is generated at one loop in most cases. The current constraints on charged Lepton Flavour Violation therefore suggest that mu <---> e flavour-changing NSI are unobservable and tau <---> l flavour-changing NSI are an order of magnitude weaker than the weak interactions. This conclusion can be avoided if the heavy New Physics conspires to cancel the one-loop LFV, or if NSI are generated by light New Physics to which our analysis does not apply.
hep-phPRD(2020)·18 citations
19*
Associated production of SM Higgs with a photon in type-II seesaw models at the ILC
L. Rahili🇲🇦 · A. Arhrib🇲🇦 · R. Benbrik🇲🇦
We consider the production of a single Standard Model (SM) Higgs boson ( $h^{0}$ ) in association with a photon at the future Linear collider (LC) in the context of a type-II seesaw model. The type-II seesaw model extends the SM particle content by adding one triple Higgs where its Higgs coupling is a key parameter of the scalar potential triggering the electroweak symmetry-breaking mechanism in the SM. It is a well motivated model since it provides neutrino masses and mixing. The LC presents a particularly interesting possibility to probe Higgs couplings due to the clean beams in the initial state. We study the one loop processes $e^{+} e^{-} \to h^{0} γ$ and $e^{-} γ \to e^{-} h^{0}$ , we show that it is possible to correlate the total cross section predictions with the couplings $h^{0} γ γ$ and $h^{0} γ Z$ which are sensitive to the presence of singly and doubly charged Higgs. For parameter points allowed by the current experimental constraints, our numerical results show that the effect of $H^{\pm}$ and $H^{\pm\pm}$ can be as large as $\pm$ 25\% with respect to the SM predictions. For both processes, we also present differential cross section for different center of mass energy.
hep-phEPJC(2019)·14 citations
20*
Interpreting cosmological tensions from the effective field theory of torsional gravity
Sheng-Feng Yan🇨🇳 · Pierre Zhang🇨🇳 · Jie-Wen Chen🇨🇳 · Xin-Zhe Zhang🇨🇳 · Yi-Fu Cai🇨🇳 · Emmanuel N. Saridakis🇬🇷
Cosmological tensions can arise within $Λ$ CDM scenario amongst different observational windows, which may indicate new physics beyond the standard paradigm if confirmed by measurements. In this article, we report how to alleviate both the $H_{0}$ and $σ_{8}$ tensions simultaneously within torsional gravity from the perspective of effective field theory (EFT). Following these observations, we construct concrete models of Lagrangians of torsional gravity. Specifically, we consider the parametrization $f (T) = - T - 2Λ/ M_{P}^{2} + α T^{β}$ , where two out of the three parameters are independent. This model can efficiently fit observations solving the two tensions. To our knowledge, this is the first time where a modified gravity theory can alleviate both $H_{0}$ and $σ_{8}$ tensions simultaneously, hence, offering an additional argument in favor of gravitational modification.
↳ astro-ph.COgr-qchep-phPRD(2020)·113 citations
21*
Thermal effects of Very Special Relativity Quantum Electrodynamics
R. Bufalo🇧🇷 · M. Ghasemkhani🇮🇷
In this paper we compute the high-temperature effective Lagrangian for the quantum electrodynamics defined in the framework of Very Special Relativity (VSR). The main aspect of the VSR setting is that it modifies the gauge invariance, admitting now different types of interactions appearing in a nonlocal form. In order to explore the richness of these new couplings, we employ the usual Matsubara imaginary-time formalism to evaluate the effective Lagrangian at one and two-loop order. We illustrate the leading VSR Lorentz violation modifications by computing high-temperature internal energy density and establishing a comparison with the expected contribution.
↳ hep-thhep-phPRD(2019)·12 citations
22*
Gauging 1-form center symmetries in simple $S U (N)$ gauge theories
Stefano Bolognesi🇮🇹 · Kenichi Konishi🇮🇹 · Andrea Luzio🇮🇹
Consequences of gauging exact $Z_{k}^{C}$ center symmetries in several simple $S U (N)$ gauge theories, where $k$ is a divisor of $N$ , are investigated. Models discussed include: the $S U (N)$ gauge theory with $N_{f}$ copies of Weyl fermions in self-adjoint single-column antisymmetric representation, the well-discussed adjoint QCD, QCD-like theories in which the quarks are in a two-index representation of $S U (N)$ , and a chiral $S U (N)$ theory with fermions in the symmetric as well as in anti-antisymmetric representations but without fundamentals. Mixed 't Hooft anomalies between the 1-form $Z_{k}^{C}$ symmetry and some 0-form (standard) discrete symmetry provide us with useful information about the infrared dynamics of the system. In some cases they give decisive indication to select only few possiblities for the infrared phase of the theory.
↳ hep-thhep-lathep-phJHEP(2020)·35 citations
23*
Determination of proton parton distribution functions using ATLAS data
Francesco Giuli🇮🇹
Fits to determine parton distribution functions using top-antitop, inclusive $W / Z$ boson and $W^{\pm}$ boson production measurements in association with jets from ATLAS, in combination with deep-inelastic scattering data from HERA, are presented. The ATLAS $W / Z$ boson data exhibit sensitivity to the valence quark distributions and the light quark sea composition, whereas the top-quark pair production data have sensitivity to the gluon distribution. The impact of the these data is increased by fitting several distributions simultaneously, with the full information on the systematic and statistical correlations between data points. The parton distribution functions extracted using $W^{\pm}$ + jets data show an improved determination of the high- $x$ sea-quark densities, while confirming the unsuppressed strange-quark density at lower $x$ < 0.02 found by previous ATLAS analyses.
↳ hep-exhep-phPoS(2020)·3 citations
24*
Coupled Channel Analysis of $p ˉ p \to π^{0} π^{0} η$ , $π^{0} η η$ and $K^{+} K^{-} π^{0}$ at 900 $M e V / c$ and of $π π$ -Scattering Data
Crystal Barrel Collaboration: M. Albrecht🇩🇪 · C. Amsler🇨🇭 · W. Dünnweber🇩🇪 · M.A. Faessler🇩🇪 · F.H. Heinsius🇩🇪 · H. Koch🇩🇪 · B. Kopf🇩🇪 · U. Kurilla🇩🇪 · C.A. Meyer🇺🇸 · K. Peters🇩🇪 · J. Pychy🇩🇪 · X. Qin🇩🇪 · M. Steinke🇩🇪 · U. Wiedner🇩🇪
A partial wave analysis of antiproton-proton annihilation data in flight at 900 $M e V / c$ into $π^{0} π^{0} η$ , $π^{0} η η$ and $K^{+} K^{-} π^{0}$ is presented. The data were taken at LEAR by the Crystal Barrel experiment in 1996. The three channels have been coupled together with $π π$ -scattering isospin I=0 S- and D-wave as well as I=1 P-wave data utilizing the K-matrix approach. Analyticity is treated using Chew-Mandelstam functions. In the fit all ingredients of the K-matrix, including resonance masses and widths, were treated as free parameters. In spite of the large number of parameters, the fit results are in the ballpark of the values published by the Particle Data Group. In the channel $π^{0} π^{0} η$ a significant contribution of the spin exotic $I^{G} = 1^{-}$ $J^{P C} = 1^{-+}$ $π_{1}$ -wave with a coupling to $π^{0} η$ is observed. Furthermore the contributions of $ϕ (1020) π^{0}$ and $K^{*} (892)^{\pm} K^{\mp}$ in the channel $K^{+} K^{-} π^{0}$ have been studied in detail. The differential production cross section for the two reactions and the spin-density-matrix elements for the $ϕ (1020)$ and $K^{*} (892)^{\pm}$ have been extracted. No spin-alignment is observed for both vector mesons. The spin density matrix elements have been also determined for the spin exotic wave.
↳ hep-exhep-phEPJC(2020)·56 citations
25*
Geometrized quantum Galileons
Lavinia Heisenberg🇨🇭 · Christian F. Steinwachs🇩🇪
We investigate the renormalization structure of the scalar Galileon model in flat spacetime by calculating the one-loop divergences in a closed geometric form. The geometric formulation is based on the definition of an effective Galileon metric and allows to apply known heat-kernel techniques. The result for the one-loop divergences is compactly expressed in terms of curvature invariants of the effective Galileon metric and corresponds to a resummation of the divergent one-loop contributions of all n-point functions. The divergent part of the one-loop effective action therefore serves as generating functional for arbitrary n-point counterterms. We discuss our result within the Galileon effective field theory and give a brief outlook on extensions to more general Galileon models in curved spacetime.
↳ hep-thgr-qchep-phJCAP(2020)·18 citations
26*
Improvement of heavy flavor productions in a multi-phase transport model updated with modern nPDFs
L. Zheng🇨🇳 · C. Zhang🇨🇳 · S.S. Shi🇨🇳 · Z.W. Lin🇺🇸
Recently we have updated a multi-phase transport (AMPT) model with modern parton distribution functions of nuclei (nPDFs). Here we study open charm production in the updated AMPT model and compare to the experimental data from $pp$ and $AA$ collisions over a wide range of collision energies. Besides the update of nPDFs, we have removed the transverse momentum cutoff on initial heavy quark productions and also included the resultant heavy flavor cross section into the total minijet cross section in the initial condition as described by the HIJING model. We show that the AMPT model with these updates provides a much better description of the yields and transverse momentum spectra of various open charm hadrons in comparison with the experimental data. This lays the foundation for further heavy flavor studies within the transport model approach.
↳ nucl-thhep-phnucl-exPRC(2020)·21 citations
27*
Lower tensor to scalar ratio in a SUGRA motivated inflationary potential
Rathin Adhikari🇮🇳 · Mayukh R. Gangopadhyay🇮🇳 · Yogesh🇮🇳
A scalar potential obtained from the $D$ -term in the Supergravity models, which dominates over $F$ term and is mainly responsible for the inflationary phase in the early universe, is studied. The potential with canonical kinetic terms for scalar fields in the Lagrangian, has a very slow roll feature in comparison to various other plateau type inflationary potentials. In this case, a much lower tensor-to-scalar ratio ( $r$ ) of $O (1 0^{- 3})$ is achievable. The requirement of slow roll condition for the inflation potential implies that the up type neutral scalar and the down type neutral scalar in Supergravity models are with equal field strength at the time of inflation. If this relationship holds down to the electroweak scale for the corresponding $v e v$ values of these fields, then it will indicate a higher SUSY breaking scale around 100 TeV. The predicted values of the inflationary observables are well within the 1- $σ$ bounds of the recent constraints from {\it Planck'18} observations. The era of reheating after the inflationary phase, is also studied and the bounds on the reheating temperature ( $T_{r e}$ ) is calculated for a different equation of states during reheating ( $w_{r e}$ ) for the {\it Planck'18} allowed values of the scalar spectral index ( $n_{s}$ ). For our model with $w_{r e} = 2/3$ and $w_{r e} = 1$ , after satisfying all the bounds due to gravitino overproduction, we can have big parameter space for $T_{r e}$ which is well inside {\it Planck'18} 1- $σ$ bound on $n_{s}$ .
↳ astro-ph.COhep-phGrav.Cosmol.(2022)·15 citations
28*
Spectroscopy From The Lattice: The Scalar Glueball
Ruairí Brett🇺🇸 · John Bulava🇩🇰 · Daniel Darvish🇺🇸 · Jacob Fallica🇺🇸 · Andrew Hanlon🇩🇪 · Ben Hörz🇺🇸 · Colin Morningstar🇺🇸
Lattice calculations allow us to probe the low-lying, non-perturbative spectrum of QCD using first principles numerical methods. Here we present the low-lying spectrum in the scalar sector with vacuum quantum numbers including, in fully dynamical QCD for the first time, the mixing between glueball, q-qbar, and meson-meson operators.
↳ hep-lathep-phnucl-thAIP Conf.Proc.(2020)·21 citations
29*
Predictive power of grand unification from quantum gravity
Astrid Eichhorn🇩🇰 · Aaron Held🇩🇪 · Christof Wetterich🇩🇪
If a grand-unified extension of the asymptotically safe Reuter fixed-point for quantum gravity exists, it determines free parameters of the grand-unified scalar potential. All quartic couplings take their fixed-point values in the trans-Planckian regime. They are irrelevant parameters that are, in principle, computable for a given particle content of the grand unified model. In turn, the direction of spontaneous breaking of the grand-unified gauge symmetry becomes predictable. For the flow of the couplings below the Planck mass, gauge and Yukawa interactions compete for the determination of the minimum of the effective potential.
↳ hep-thgr-qchep-phJHEP(2020)·48 citations
30*
Deep Learning the Morphology of Dark Matter Substructure
Stephon Alexander🇺🇸 · Sergei Gleyzer🇺🇸 · Evan McDonough🇺🇸 · Michael W. Toomey🇺🇸 · Emanuele Usai🇺🇸
Strong gravitational lensing is a promising probe of the substructure of dark matter halos. Deep learning methods have the potential to accurately identify images containing substructure, and differentiate WIMP dark matter from other well motivated models, including vortex substructure of dark matter condensates and superfluids. This is crucial in future efforts to identify the true nature of dark matter. We implement, for the first time, a classification approach to identifying dark matter substructure based on simulated strong lensing images with different substructure. Utilizing convolutional neural networks trained on sets of simulated images, we demonstrate the feasibility of deep neural networks to reliably distinguish among different types of dark matter substructure. With thousands of strong lensing images anticipated with the coming launch of LSST, we expect that supervised and unsupervised deep learning models will play a crucial role in determining the nature of dark matter.
↳ astro-ph.COastro-ph.IMhep-phApJ(2020)·51 citations
31*
The Science of Murray Gell-Mann
Sanjay Jain🇮🇳 · Spenta R. Wadia🇮🇳
This article summarizes some of the most important scientific contributions of Murray Gell-Mann (1929-2019). (Invited article for Current Science, Indian Academy of Sciences.)
↳ physics.hist-phhep-phhep-thnlin.AOCurr.Sci.(2019)·3 citations
32*
libGroomRL: Reinforcement Learning for Jets
Stefano Carrazza🇮🇹 · Frédéric A. Dreyer🇬🇧
In these proceedings, we present a library allowing for straightforward calls in C++ to jet grooming algorithms trained with deep reinforcement learning. The RL agent is trained with a reward function constructed to optimize the groomed jet properties, using both signal and background samples in a simultaneous multi-level training. We show that the grooming algorithm derived from the deep RL agent can match state-of-the-art techniques used at the Large Hadron Collider, resulting in improved mass resolution for boosted objects. Given a suitable reward function, the agent learns how to train a policy which optimally removes soft wide-angle radiation, allowing for a modular grooming technique that can be applied in a wide range of contexts. The neural network trained with GroomRL can be used in a FastJet analysis through the libGroomRL C++ library.
↳ physics.data-anhep-exhep-ph0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.