HEP Phenomenology·hep-ph

Fri·May 1, 2020Friday·May 1, 2020

28 papers—22 primary·6 cross-listed·reconstructed*

01*
Simulating hard photon production with WHIZARD
J. Kalinowski🇵🇱 · W. Kotlarski🇵🇱 · P. Sopicki🇵🇱 · A. F. Zarnecki🇵🇱
One of the important goals of the proposed future $e^{+} e^{-}$ collider experiments is the search for dark matter particles using different experimental approaches. The most general search approach is based on the mono-photon signature, which is expected when production of the invisible final state is accompanied by a hard photon from initial state radiation. Analysis of the energy spectrum and angular distributions of those photons can shed light on the nature of dark matter and its interactions. Therefore, it is crucial to be able to simulate the signal and background samples in a uniform framework, to avoid possible systematic biases. The WHIZARD program is a flexible tool, which is widely used by $e^{+} e^{-}$ collaborations for simulation of many different "new physics" scenarios. We propose the procedure of merging the matrix element calculations with the lepton ISR structure function implemented in WHIZARD. It allows us to reliably simulate the mono-photon events, including the two main Standard Model background processes: radiative neutrino pair production and radiative Bhabha scattering. We demonstrate that cross sections and kinematic distributions of mono-photon in neutrino pair-production events agree with corresponding predictions of the KKMC, a Monte Carlo generator providing perturbative predictions for SM and QED processes, which has been widely used in the analysis of LEP data.
hep-phEPJC(2020)·42 citations
02*
Eligibility of EFT approach to search for tqg FCNC phenomenon
E.E. Boos🇷🇺 · V.E. Bunichev🇷🇺 · L.V. Dudko🇷🇺 · M.A. Perfilov🇷🇺 · G.A. Vorotnikov🇷🇺
The Effective Field Theory (EFT) approach is widely used in the search for possible deviations from the predictions of the Standard Model. Such an approximation of possible BSM physics is valid up to a certain levels of energy scale and accuracy. In this article, we investigate potential limitation of the EFT approach related to unitarity to describe possible contributions of flavor changing neutral currents (FCNC) involving the top quark. The numerical and analytical calculations of the FCNC processes used in the EFT approach demonstrate the constant asymptotic behavior of the total cross section with increasing energy. It is shown that the EFT approach for studying the possible contribution of FCNC does not violate the restrictions following from perturbative unitarity, the asymptotic behavior of the cross section does not exceed the Froissart bound, and the approach itself can be used to set the corresponding experimental limits for FCNC couplings or Wilson coefficients at present and future colliders.
hep-phPhys.Atom.Nucl.(2020)·8 citations
03*
LSND Constraints on the Higgs Portal
Saeid Foroughi-Abari🇨🇦 · Adam Ritz🇨🇦
High-luminosity fixed target experiments provide impressive sensitivity to new light weakly coupled degrees of freedom. We revisit the minimal case of a scalar singlet $S$ coupled to the Standard Model through the Higgs portal, that decays visibly to leptons for scalar masses below the di-pion threshold. The dataset from the LSND experiment is found to impose the leading constraints within two mass windows between $m_{S} \sim 100$ and 350 MeV. In the process, we analyze a number of scalar production channels in the target, finding that proton bremsstrahlung provides the dominant channel at LSND beam energies.
hep-phPRD(2020)·54 citations
04*
Thermodynamic properties and transport coefficients of QCD matter within the non-extensive Polyakov-Nambu-Jona-Lasinio model
Ya-Peng Zhao🇨🇳
We present a non-extensive version of the Polyakov-Nambu-Jona-Lasinio model which is based on the non-extentive statistical mechanics. This new statistics is characterized by a dimensionless non-extensivity parameter $q$ that accounts for all possible effects violating the assumptions of the Boltzmann-Gibbs statistics (when $q \to 1$ , it returns to the Boltzmann-Gibbs case). Using this q-Polyakov-Nambu-Jona-Lasinio model and including two different Polyakov-loop potentials, we discussed the influence of the parameter $q$ on chiral and deconfinement phase transition, various thermodynamic quantities and transport coefficients at finite temperature and zero quark chemical potential. We found that the Stefan-Boltzmann limit is actually related to the choice of statistics. For example, in the Tsallis statistics, the thermodynamic quantities $\frac{ϵ}{T ^{4}}$ , $\frac{p}{T ^{4}}$ and $\frac{s}{T ^{3}}$ all increase with $q$ , exceed their usual Stefan-Boltzmann limits and tend to a new $q$ -related Tsallis limit at temperature high enough. Interestingly, however, due to a surprising cancellation, the high temperature limit of $c_{s}^{2}$ is still its SB limit $1/3$ . In addition, we found some similarities between the non-extensive effect and the finite-size effect. For example, as $q$ increases (size decreases), the criticality of $\frac{c _{v}}{T ^{3}}$ and $c_{s}^{2}$ gradually disappears. Besides, in order to better study the non-extensive effect, we defined a new susceptibility and calculated the response of thermodynamic quantities and transport coefficients to $q$ . And found that their response patterns are different.
hep-phnucl-thPRD(2020)·37 citations
05*
On the physics potential of ILC and CLIC
Aleksander Filip Zarnecki🇵🇱
The International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are the two options for a future high-energy, high-luminosity linear electron-positron collider. Both are expected to be built in stages, optimised for their physics potential. The main goals are the precision measurements of Higgs-boson and top-quark properties as well as direct and indirect searches for new physics Beyond Standard Model. In my talk I will review some of the latest results from both ILC and CLIC demonstrating their physics potential, pointing to similarities and complementarity of both projects.
hep-phhep-exPoS(2020)·21 citations
06*
QCD Hidden-Color Hexa-diquark in the Central Core of Nuclei
Jennifer Rittenhouse West🇺🇸 · Stanley J. Brodsky🇺🇸 · Guy F. de Teramond🇨🇷 · Alfred S. Goldhaber🇺🇸 · Ivan Schmidt🇨🇱
Hidden-color configurations are a key prediction of QCD with important physical consequences. In this work we examine a QCD color-singlet configuration in nuclei formed by combining six scalar $[u d]$ diquarks in a strongly bound $SU (3)_{C}$ channel. The resulting hexadiquark state is a charge-2, spin-0, baryon number-4, isospin-0, color-singlet state. It contributes to alpha clustering in light nuclei and to the additional binding energy not saturated by ordinary nuclear forces in \he as well as the alpha-nuclei sequence of interest for nuclear astrophysics. We show that the strongly bound combination of six scalar isospin-0 $[u d]$ diquarks within the nuclear wave function - relative to free nucleons - provides a natural explanation of the EMC effect measured by the CLAS collaboration's comparison of nuclear parton distribution function ratios for a large range of nuclei. These experiments confirmed that the EMC effect; i.e., the distortion of quark distributions within nuclei, is dominantly identified with the dynamics of neutron-proton (``isophobic'') short-range correlations within the nuclear wave function rather than proton-proton or neutron-neutron correlations.
hep-phnucl-exnucl-thNPA(2021)·20 citations
07*
New physics in $b \to s ℓℓ$ decays with complex Wilson coefficients
Aritra Biswas🇮🇳 · Soumitra Nandi🇮🇳 · Ipsita Ray🇮🇳 · Sunando Kumar Patra🇮🇳
We perform a data-driven analysis of new physics (NP) effects in exclusive $b \to s ℓ^{+} ℓ^{-}$ decays in a model-independent effective theory approach with dimension six operators considering scalar, pseudo-scalar, vector and axial-vector operators with the corresponding Wilson coefficients (WC) taken to be complex. The analysis has been done with the most recent data while comparing the outcome with that from the relatively old data-set. We find that a left-handed quark current with vector muon coupling is the only one-operator $(O_{9})$ scenario that can explain the data in both the cases with real and complex WC with a large non-zero imaginary contribution. We simultaneously apply model selection tools like cross-validation and information-theoretic approach like Akaike Information Criterion (AIC) to find out the operator or sets of operators that can best explain the available data in this channel. The $O_{9}$ with complex WC is the only one-operator scenario which survives the test. However, there are a few two and three-operator scenarios (with real or complex WCs) which survive the test, and the operator $O_{9}$ is common among them.
hep-phhep-exNPB(2021)·53 citations
08*
Potential-driven Inflation with Disformal Coupling to Gravity
Taotao Qiu🇨🇳 · Zehua Xiao🇨🇳 · Jiaming Shi🇨🇳 · Muhsin Aljaf🇨🇳
In this paper, we investigate the potential-driven inflation models with a disformal coupling to Einstein Gravity, to find out the effects of such a coupling on these models. We consider a simple coupling form which introduces only one parameter, and three inflation models, namely the chaotic inflation, the Higgs inflation, and the monodromy inflation. We find that the disformal coupling can have some modifications to the observational variables of these models such as the power spectrum, the spectral index as well as the tensor/scalar ratio, although not too large due to the constraints on the disformal coupling parameter. With these modifications, one has the opportunity of improving models that lie on the edge of the favorable regions of Planck observational data, such as monodromy inflation. Moreover, the non-trivial sound speed of tensor perturbations (gravitational waves) may come out, due to the coupling of gravity and kinetic terms of the field.
hep-phastro-ph.COgr-qchep-thPRD(2020)·4 citations
09*
High frequency gravitational waves from spin-3/2 fields
Karim Benakli🇫🇷
We point out the peculiar form of the gravitational wave signal expected from a gas of particles carry spin 3/2 produced during preheating. Given the very few ways that gravitinos can manifest themselves in an experimentally observable way, we stress the importance of improving the sensitivity of ultra-high frequency detectors in the future. This review is based on work that appeared in [arXiv:1811.11774 [hep-ph]].
hep-phInt.J.Mod.Phys.A(2020)·2 citations
10*
Are 3-4-1 models able to explain the upcoming results of the muon anomalous magnetic moment?
D. Cogollo🇧🇷 · Yohan M. Oviedo-Torres🇧🇷 · Yoxara S. Villamizar🇧🇷
In light of the upcoming measurement of the muon anomalous magnetic moment (g-2), we revisit the corrections to g-2 in the context of the $S U (4)_{L} \times U (1)_{X}$ gauge symmetry. We investigate three models based on this gauge symmetry and express our results in terms of the energy scale at which the $S U (4)_{L} \times U (1)_{X}$ symmetry is broken. To draw solid conclusions we put our findings into perspective with existing collider bounds. Lastly, we highlight the difference between our results and those rising from $S U (3)_{L} \times U (1)_{X}$ constructions.
hep-phInt.J.Mod.Phys.A(2020)·10 citations
11*
One-loop Matching for Spin-Dependent Quasi-TMDs
Markus A. Ebert🇺🇸 · Stella T. Schindler🇺🇸 · Iain W. Stewart🇺🇸 · Yong Zhao🇺🇸
Transverse momentum dependent parton distribution functions (TMDPDFs) provide a unique probe of the three-dimensional spin structure of hadrons. We construct spin-dependent quasi-TMDPDFs that are amenable to lattice QCD calculations and that can be used to determine spin-dependent TMDPDFs. We calculate the short-distance coefficients connecting spin-dependent TMDPDFs and quasi-TMDPDFs at one-loop order. We find that the helicity and transversity distributions have the same coefficient as the unpolarized TMDPDF. We also argue that the same is true for pretzelosity and that this spin universality of the matching will hold to all orders in $α_{s}$ . Thus, it is possible to calculate ratios of these distributions as a function of longitudinal momentum and transverse position utilizing simpler Wilson line paths than have previously been considered.
hep-phhep-latnucl-thJHEP(2020)·55 citations
12*
Phenomenology of a Supersymmetric Model Inspired by Inflation
Wolfgang Gregor Hollik🇩🇪 · Cheng Li🇩🇪 · Gudrid Moortgat-Pick🇩🇪 · Steven Paasch🇩🇪
The current challenges in High Energy Physics and Cosmology are to build coherent particle physics models to describe the phenomenology at colliders in the laboratory and the observations in the universe. From these observations, the existence of an inflationary phase in the early universe gives guidance for particle physics models. We study a supersymmetric model which incorporates successfully inflation by a non-minimal coupling to supergravity and shows a unique collider phenomenology. Motivated by experimental data, we set a special emphasis on a new singlet-like state at 97 GeV and single out possible observables for a future linear collider that permit a distinction of the model from a similar scenario without inflation. We define a benchmark scenario that is in agreement with current collider and Dark Matter constraints, and study the influence of the non-minimal coupling on the phenomenology. Measuring the singlet-like state with high precision on the percent level seems to be promising for resolving the models, even though the Standard Model-like Higgs couplings deviate only marginally. However, a hypothetical singlet-like state with couplings of about 20% compared to a Standard Model Higgs at 97 GeV encourages further studies of such footprint scenarios of inflation.
hep-phhep-exEPJC(2021)·20 citations
13*
Tri-Partite entanglement in Neutrino Oscillations
Abhishek Kumar Jha🇮🇳 · Supratik Mukherjee🇮🇳 · Bindu A. Bambah🇮🇳
We investigate and quantify various measures of bipartite and tripartite entanglement in the context of two and three flavor neutrino oscillations. The bipartite entanglement is analogous to the entanglement swapping resulting from a beam splitter in quantum optics. For the three neutrino systems various measures of tripartite entanglement are explored. The significant result is that a monogamy inequality in terms of negativity leads to a residual entanglement, implying true tripartite entanglement in the three neutrino system. This leads us to an analogy of the three neutrino state with a generalized class of W-state in quantum optics.
hep-phquant-phMod.Phys.Lett.A(2021)·33 citations
14*
Improved Treatment of Dark Matter Capture in Neutron Stars
Nicole F. Bell🇦🇺 · Giorgio Busoni🇩🇪 · Sandra Robles🇦🇺 · Michael Virgato🇦🇺
Neutron stars provide a cosmic laboratory to study the nature of dark matter particles and their interactions. Dark matter can be captured by neutron stars via scattering, where kinetic energy is transferred to the star. This can have a number of observational consequences, such as the heating of old neutron stars to infra-red temperatures. Previous treatments of the capture process have employed various approximation or simplifications. We present here an improved treatment of dark matter capture, valid for a wide dark matter mass range, that correctly incorporates all relevant physical effects. These include gravitational focusing, a fully relativistic scattering treatment, Pauli blocking, neutron star opacity and multi-scattering effects. We provide general expressions that enable the exact capture rate to be calculated numerically, and derive simplified expressions that are valid for particular interaction types or mass regimes and that greatly increase the computational efficiency. Our formalism is applicable to the scattering of dark matter from any neutron star constituents, or to the capture of dark matter in other compact objects.
hep-phastro-ph.COastro-ph.HEJCAP(2020)·147 citations
15*
Master Integrals for the mixed QCD-QED corrections to the Drell-Yan production of a massive lepton pair
Syed Mehedi Hasan🇮🇹 · Ulrich Schubert🇺🇸
We showcase the calculation of the master integrals needed for the two loop mixed QCD-QED virtual corrections to the neutral current Drell-Yan process $(q q ˉ \to l^{+} l^{-})$ . After establishing a basis of 51 master integrals, we cast the latter into canonical form by using the Magnus algorithm. The dependence on the lepton mass is then expanded such that potentially large logarithmic contributions are kept. After determining all boundary constants, we give the coefficients of the Taylor series around four space-time dimensions in terms of generalized polylogarithms up to weight four.
hep-phJHEP(2020)·23 citations
16*
Learning Physics at Future $e^{-} e^{+}$ Colliders with Machine
Lingfeng Li🇨🇳 · Ying-Ying Li🇺🇸 · Tao Liu🇨🇳 · Si-Jun Xu🇨🇳
Information deformation and loss in jet clustering are one of the major limitations for precisely measuring hadronic events at future $e^{-} e^{+}$ colliders. Because of their dominance in data, the measurements of such events are crucial for advancing the precision frontier of Higgs and electroweak physics in the next decades. We show that this difficulty can be well-addressed by synergizing the event-level information into the data analysis, with the techniques of deep neutral network. In relation to this, we introduce a CMB-like observable scheme, where the event-level kinematics is encoded as Fox-Wolfram (FW) moments at leading order and multi-spectra at higher orders. Then we develop a series of jet-level (w/ and w/o the FW moments) and event-level classifiers, and analyze their sensitivity performance comparatively with two-jet and four-jet events. As an application, we analyze measuring Higgs decay width at $e^{-} e^{+}$ colliders with the data of 5ab $^{- 1} @$ 240GeV. The precision obtained is significantly better than the baseline ones presented in documents. We expect this strategy to be applied to many other hadronic-event measurements at future $e^{-} e^{+}$ colliders, and to open a new angle for evaluating their physics capability.
hep-phhep-exJHEP(2020)·13 citations
17*
Complete Set of Dimension-8 Operators in the Standard Model Effective Field Theory
Hao-Lin Li🇨🇳 · Zhe Ren🇨🇳 · Jing Shu🇨🇳 · Ming-Lei Xiao🇨🇳 · Jiang-Hao Yu🇨🇳 · Yu-Hui Zheng🇨🇳
We present a complete list of the dimension 8 operator basis in the standard model effective field theory using group theoretic techniques in a systematic and automated way. We adopt a new form of operators in terms of the irreducible representations of the Lorentz group, and identify the Lorentz structures as states in a $S U (N)$ group. In this way, redundancy from equations of motion is absent and that from integration-by-part is treated using the fact that the independent Lorentz basis forms an invariant subspace of the $S U (N)$ group. We also decompose operators into the ones with definite permutation symmetries among flavor indices to deal with subtlety from repeated fields. For the first time, we provide the explicit form of independent flavor-specified operators in a systematic way. Our algorithm can be easily applied to higher dimensional standard model effective field theory and other effective field theories, making these studies more approachable.
hep-phPRD(2021)·307 citations
18*
Pati-Salam Axion
Luca Di Luzio🇩🇪
I discuss the implementation of the Peccei-Quinn mechanism in a minimal realization of the Pati-Salam partial unification scheme. The axion mass is shown to be related to the Pati-Salam breaking scale and it is predicted via a two-loop renormalization group analysis to be in the window $m_{a} \in [1 0^{- 11}, 3 \times 1 0^{- 7}]$ eV, as a function of a sliding Left-Right symmetry breaking scale. This parameter space will be fully covered by the late phases of the axion Dark Matter experiments ABRACADABRA and CASPEr-Electric. A Left-Right symmetry breaking scenario as low as 20 TeV is obtained for a Pati-Salam breaking of the order of the reduced Planck mass.
hep-phJHEP(2020)·11 citations
19*
Minimal 3-loop neutrino mass models and charged lepton flavor violation
Ricardo Cepedello🇪🇸 · Martin Hirsch🇪🇸 · Paulina Rocha-Morán🇩🇪 · Avelino Vicente🇪🇸
We study charged lepton flavor violation for the three most popular 3-loop Majorana neutrino mass models. We call these models "minimal" since their particle content correspond to the minimal sets for which genuine 3-loop models can be constructed. In all the three minimal models the neutrino mass matrix is proportional to some powers of Standard Model lepton masses, providing additional suppression factors on top of the expected loop suppression. To correctly explain neutrino masses, therefore large Yukawa couplings are needed in these models. We calculate charged lepton flavor violating observables and find that the three minimal models survive the current constraints only in very narrow regions of their parameter spaces.
hep-phJHEP(2020)·14 citations
20*
Open charm and charmonium states in strong magnetic fields
Amruta Mishra🇮🇳 · S.P.Misra🇮🇳
The mass modifications of the open charm ( $D$ and $D^{*}$ ) mesons, and their effects on the decay widths $D^{*} \to D π$ as well as of the charmonium state, $Ψ (3770)$ to open charm mesons ( $Ψ (3770) \to D D ˉ$ ), are investigated in the presence of strong magnetic fields. These are studied accounting for the mixing of the pseudoscalar ( $P$ ) and vector ( $V$ ) mesons ( $D - D^{*}$ , $η_{c}^{'} - Ψ (3770)$ mixings), with the mixing parameter, $g_{P V}$ of a phenomenological three-point ( $P V γ$ ) vertex interaction determined from the observed radiative decay width of $V \to P γ$ . For charged $D - D^{*}$ mixing, this parameter is dependent on the magnetic field, because of the Landau level contributions to the vacuum masses of these mesons. The masses of the charged $D$ and $D^{*}$ mesons modified due to $P V$ mixing, in addition, have contributions from the lowest Landau levels in the presence of a strong magnetic field. The effects of the magnetic field on the decay widths are studied using a field theoretic model of composite hadrons with quark (and antiquark) consittuents. The parameter for the charged $D - D^{*}$ mixing is observed to increase appreciably with increase in the magnetic field. This leads to dominant modifications to their masses, and hence the decay widths of charged $D^{*} \to D π$ as well as $Ψ (3770) \to D^{+} D^{-}$ at large values of the magnetic field. The modifications of the masses and decay widths of the open and hidden charm mesons in the presence of strong magnetic fields should have observable consequences on the production of the open charm ( $D$ and $D^{*}$ ) mesons as well as of the charmonium states resulting from non-central ultrarelativistic heavy ion collision experiments.
hep-phnucl-thIJMPE(2021)·22 citations
21*
Why Neutrino Masses Cannot Arise from Nonzero VEV of Charged Higgs Field in the Only Higgs Doublet
Jianlong Lu🇸🇬
A scheme of neutrino mass generation is proposed by [arXiv:2003.12069], in which the small nonzero neutrino masses come from nonzero vacuum expectation value (VEV) of the charged Higgs field in the Higgs doublet in the Standard Model of particle physics (SM). However, the introduction of nonzero VEV for the charged Higgs field implies broken $U (1)$ symmetry in the electroweak theory, which leads to non-conservation of electric charge and nonzero mass of photon. By comparing the predicted ratio of VEVs of charged Higgs field and neutral Higgs field in [1] with the ratio constrained by the present experimental upper bound of photon mass, we show that this scheme does not work.
hep-ph1 citation
22*
Tritonlike molecules of three identical baryons
Li Ma🇨🇳
In nuclear physics, triton and helium-3 nucleus can be understood as three-body hadronic molecules. Analogous to the loosely bound structures for the triton and helium-3 nucleus, whether there is a bound state formed by three hadrons leaves us an open issue. Based on the one-boson exchange model as well as the adoption of the variational approach, we make a comprehensive investigation on the tritonlike systems of three identical baryons $N N N$ , $ΛΛΛ$ , $ΞΞΞ$ and $ΣΣΣ$ . We predict that the three-body molecular states for the systems of three identical hadrons of baryon octet are probably existent as long as their two-body subsystems have bound states. The numerical results of this work may be helpful for the theoretical and experimental researches on the tri-hadron molecules in future.
hep-phnucl-thAdv.High Energy Phys.(2022)·0 citations
23*
On the canonical formulation of gauge field theories and Poincare transformations
Daniel N. Blaschke🇺🇸 · Francois Gieres🇫🇷
We address the Hamiltonian formulation of classical gauge field theories while putting forward results some of which are not entirely new, though they do not appear to be well known. We refer in particular to the fact that neither the canonical energy momentum vector $(P^{μ})$ nor the gauge invariant energy momentum vector $(P_{inv}^{μ})$ do generate space-time translations of the gauge field by means of the Poisson brackets: In a general gauge, one has to consider the so-called kinematical energy momentum vector and, in a specific gauge (like the radiation gauge in electrodynamics), one has to consider the Dirac brackets rather than the Poisson brackets. Similar arguments apply to rotations and to Lorentz boosts and are of direct relevance to the "nucleon spin crisis" since the spin of the proton involves a contribution which is due to the angular momentum vector of gluons and thereby requires a proper treatment of the latter. We conclude with some comments on the relationships between the different approaches to quantization (canonical quantization based on the classical Hamiltonian formulation, Gupta-Bleuler, path integrals, BRST, covariant canonical approaches).
↳ hep-thhep-phnucl-thNPB(2021)·11 citations
24*
Classification of Equation of State in Relativistic Heavy-Ion Collisions Using Deep Learning
Yu. Kvasiuk🇳🇴 · E. Zabrodin🇳🇴 · L. Bravina🇳🇴 · I. Didur🇺🇦 · M. Frolov🇺🇦
Convolutional Neural Nets, which is a powerful method of Deep Learning, is applied to classify equation of state of heavy-ion collision event generated within the UrQMD model. Event-by-event transverse momentum and azimuthal angle distributions of protons are used to train a classifier. An overall accuracy of classification of 98\% is reached for Au+Au events at $s_{N N} = 11$ GeV. Performance of classifiers, trained on events at different colliding energies, is investigated. Obtained results indicate extensive possibilities of application of Deep Learning methods to other problems in physics of heavy-ion collisions.
↳ nucl-thcs.LGhep-phnucl-exJHEP(2020)·12 citations
25*
Constraining the quadrupole deformation of atomic nuclei with relativistic nuclear collisions
Giuliano Giacalone🇫🇷
Preliminary data by the STAR collaboration at the BNL Relativistic Heavy Ion Collider shows that the elliptic flow, $v_{2}$ , and the average transverse momentum, $⟨ p_{t} ⟩$ , of final-state hadrons produced in high-multiplicity $^{238}$ U+ $^{238}$ U collisions are negatively correlated. This observation brings experimental evidence of a significant prolate deformation, $β \approx 0.3$ , in the colliding $^{238}$ U nuclei. I show that a quantitative description of this new phenomenon can be achieved within the hydrodynamic framework of heavy-ion collisions, and that thus such kind of data in the context of high-energy nuclear experiments can help constrain the quadrupole deformation of the colliding species.
↳ nucl-thhep-exhep-phnucl-exPRC(2020)·71 citations
26*
Non-Cold Dark Matter from Primordial Black Hole Evaporation
Iason Baldes🇧🇪 · Quentin Decant🇧🇪 · Deanna C. Hooper🇧🇪 · Laura Lopez-Honorez🇧🇪
Dark matter coupled solely gravitationally can be produced through the decay of primordial black holes in the early universe. If the dark matter is lighter than the initial black hole temperature, it could be warm enough to be subject to structure formation constraints. In this paper we perform a more precise determination of these constraints. We first evaluate the dark matter phase-space distribution, without relying on the instantaneous decay approximation. We then interface this phase-space distribution with the Boltzmann code CLASS to extract the corresponding matter power spectrum, which we find to match closely those of warm dark matter models, albeit with a different dark matter mass. This mapping allows us to extract constraints from Lyman- $α$ data without the need to perform hydrodynamical simulations. We robustly rule out the possibility, consistent with previous analytic estimates, of primordial black holes having come to dominate the energy density of the universe and simultaneously given rise to all the DM through their decay. Consequences and implications for dark radiation and leptogenesis are also briefly discussed.
↳ astro-ph.COhep-phJCAP(2020)·162 citations
27*
Implications of the weak gravity conjecture in anomalous quiver gauge theories
Yoshihiko Abe🇯🇵 · Tetsutaro Higaki🇯🇵 · Rei Takahashi🇯🇵
We argue a smallness of gauge couplings in abelian quiver gauge theories, taking the anomaly cancellation condition into account. In theories of our interest there exist chiral fermions leading to chiral gauge anomalies, and an anomaly-free gauge coupling tends to be small, and hence can give a non-trivial condition of the weak gravity conjecture. As concrete examples, we consider $U (1)^{k}$ gauge theories with a discrete symmetry associated with cyclic permutations between the gauge groups, and identify anomaly-free $U (1)$ gauge symmetries and the corresponding gauge couplings. Owing to this discrete symmetry, we can systematically study the models and we find that the models would be examples of the weak coupling conjecture. It is conjectured that a certain class of chiral gauge theories with too many $U (1)$ symmetries may be in the swampland. We also numerically study constraints on the couplings from the scalar weak gravity conjecture in a concrete model. These constraints may have a phenomenological implication to model building of a chiral hidden sector as well as the visible sector.
↳ hep-thhep-phPRD(2020)·3 citations
28*
Non-local Entanglement and Fast Scrambling in De-Sitter Holography
Hao Geng🇺🇸
We study holographic entanglement and information scrambling in de-Sitter (dS) space in the context of the DS/dS correspondence. We find that our previously identified non-local entanglement structure of dS vacua can be extended out of the time-reflection symmetric slice. We extend the geometry to a two-sided configuration and calculate the zero-time mutual information between two intervals on different sides when there is a localized shock wave in the bulk. Interestingly, we find that the information scrambling time saturates the fast scrambler bound proposed by Sekino and Susskind and that the shock wave renders a wormhole to be traversable. Furthermore, we calculate a two-sided out-of-time-ordered correlator (OTOC) in the late time regime and we see that, before scrambling, it exponentially grows with an exponent whose value saturates the maximal bound of chaos proposed by Maldacena, Shenker and Stanford. At the end, we provide an explanation why the exponential growing of the late-time OTOC with the maximal bound of chaos saturated and the traversability of the wormhole are simple results of the non-local entanglement structure and point out that this is a realization of the ER=EPR proposal.
↳ hep-thgr-qchep-phquant-phAnnals Phys.(2021)·69 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.