HEP Phenomenology·hep-ph

Thu·Aug 29, 2019Thursday·August 29, 2019

20 papers—11 primary·9 cross-listed·reconstructed*

01*
Gluonic Probe for the Short Range Correlation in Nucleus
Ji Xu🇨🇳 · Feng Yuan🇺🇸
We investigate the gluonic probe to the nucleon-nucleon short range correlation (SRC) in nucleus through heavy flavor production in deep inelastic scattering (DIS). The relevant EMC effects of $F_{2}^{c c ˉ}$ structure function will provide a universality test of the SRCs which have been extensively studied in the quark-channel. These SRCs can also be studied through the sub-threshold production of heavy flavor in $e A$ collisions at the intermediate energy electron-ion collider, including open Charm and $J / ψ$ ( $Υ$ ) production.
hep-phnucl-exnucl-thPLB(2020)·21 citations
02*
Cold quark matter with heavy quarks and the stability of charm stars
José C. Jiménez🇧🇷 · Eduardo S. Fraga🇧🇷
We study the effects of heavy quarks on the equation of state for cold and dense quark matter obtained from perturbative QCD, yielding observables parametrized only by the renormalization scale. We investigate the thermodynamics of charm quark matter under the constraints of $β$ equilibrium and electric charge neutrality in a region of densities where perturbative QCD is, in principle, much more reliable. We also analyze the stability of charm stars, which might be realized as a new branch of ultradense hybrid compact stars, and find that such quark stars are unstable under radial oscillations.
hep-phastro-ph.HEgr-qchep-lat+1PRD(2020)·8 citations
03*
Particle Probes with Superradiant Pulsars
David E. Kaplan🇺🇸 · Surjeet Rajendran🇺🇸 · Paul Riggins🇺🇸
We demonstrate that rotational superradiance can be efficient in millisecond pulsars. Measurements from the two fastest known pulsars PSR J1748-2446ad and PSR B1937+21 can place bounds on bosons with masses below 10^{-11} eV. The bounds are maximally good at masses corresponding to the rotation rate of the star, where scalar interactions that mediate forces ~ 10^6 times weaker than gravity are ruled out, exceeding existing fifth force constraints by 3 orders of magnitude. For certain neutron star equations of state, these measurements would also constrain the QCD axion with masses between 5 10^{-13} and 3 10^{-12} eV. Despite the ability of most neutron star equations of state to support frequencies as high as ~ 1500 Hz, the observed absence of pulsars above ~ 700 Hz could be due to the existence of a new particle of mass ~ 10^{-11} eV with a Yukawa coupling to nucleons.
hep-phastro-ph.HEgr-qchep-th16 citations
04*
Probing the Symmetric Higgs Portal with Di-Higgs Boson Production
Christoph Englert🇬🇧 · Joerg Jaeckel🇩🇪
A coupling of a scalar, charged under an unbroken global U(1) symmetry, to the Standard Model via the Higgs portal is one of the simplest gateways to a dark sector. Yet, for masses $m_{S} \geq m_{H} /2$ there are few probes of such an interaction. In this note we evaluate the sensitivity to the Higgs portal coupling of di-Higgs boson production at the LHC as well as at a future high energy hadron collider, FCC-hh, taking into account the full momentum dependence of the process. This significantly impacts the sensitivity compared to estimates of changes in the Higgs-coupling based on the effective potential. We also compare our findings to precision single Higgs boson probes such as the cross section for vector boson associated Higgs production at a future lepton collider, e.g. FCC-ee, as well as searches for missing energy based signatures.
hep-phhep-exPRD(2019)·22 citations
05*
Interacting hadron resonance gas model in magnetic field and the fluctuations of conserved charges
Guruprasad Kadam🇮🇳 · Somenath Pal🇮🇳 · Abhijit Bhattacharyya🇮🇳
In this paper we discuss the interacting hadron resonance gas model in presence of a constant external magnetic field. The short range repulsive interaction between hadrons are accounted through van der Waals excluded volume correction to the ideal gas pressure. Here we take the sizes of hadrons as $r_{π}$ (pion radius) $= 0$ fm, $r_{K}$ (kaon radius) $= 0.35$ fm, $r_{m}$ (all other meson radii) $= 0.3$ fm and $r_{b}$ (baryon radii) $= 0.5$ fm. We analyse the effect of uniform background magnetic field on the thermodynamic properties of interacting hadron gas. We especially discuss the effect of interactions on the behaviour of magnetization of low temperature hadronic matter. The vacuum terms have been regularized using magnetic field independent regularization scheme. We find that the magnetization of hadronic matter is positive which implies that the low temperature hadronic matter is paramagnetic. We further find that the repulsive interactions have very negligible effect on the overall magnetization of the hadronic matter and the paramagnetic property of the hadronic phase remains unchanged. We have also investigated the effects of short range repulsive interactions as well as the magnetic field on the baryon and electric charge number susceptibilities of hadronic matter within the ambit of excluded volume hadron resonance gas model.
hep-phnucl-thJ.Phys.G(2020)·28 citations
06*
Magnetic field driven enhancement of the weak decay width of charged pions
M. Coppola🇦🇷 · D. Gomez Dumm🇦🇷 · S. Noguera🇪🇸 · N. N. Scoccola🇦🇷
We study the effect of a uniform magnetic field $B$ on the decays $π^{-} \to l^{-} ν ˉ_{l}$ , where $l^{-} = e^{-}, μ^{-}$ , carrying out a general analysis that includes four $π^{-}$ decay constants. Taking the values of these constants from a chiral effective Nambu-Jona--Lasinio (NJL) model, it is seen that the total decay rate gets strongly increased with respect to the $B = 0$ case, with an enhancement factor ranging from $\sim 10$ for $e B = 0.1 GeV^{2}$ up to $\sim 1 0^{3}$ for $e B = 1 GeV^{2}$ . The ratio between electronic and muonic decays gets also enhanced, reaching a value of about $1 : 2$ for $e B = 1 GeV^{2}$ . In addition, we find that for large $B$ the angular distribution of outgoing antineutrinos shows a significant suppression in the direction of the magnetic field.
hep-phhep-latJHEP(2020)·14 citations
07*
Investigating extended scalar sectors at current and future colliders
Tania Robens🇭🇷
In this work, I briefly report on constraints that can be obtained on new physics models that extend the scalar sector of the Standard Model (SM) of particle physics at the LHC. I concentrate on a few simple examples which serve to demonstrate advantages as well as possible drawbacks of current experimental searches, and comment on the discovery prospects of such models at future colliders.
hep-phPoS(2019)·6 citations
08*
High dimensional parameter tuning for event generators
Johannes Bellm🇸🇪 · Leif Gellersen🇸🇪
Monte Carlo Event Generators are important tools for the understanding of physics at particle colliders like the LHC. In order to best predict a wide variety of observables, the optimization of parameters in the Event Generators based on precision data is crucial. However, the simultaneous optimization of many parameters is computationally challenging. We present an algorithm that allows to tune Monte Carlo Event Generators for high dimensional parameter spaces. To achieve this we first split the parameter space algorithmically in subspaces and perform a Professor tuning on the subspaces with bin wise weights to enhance the influence of relevant observables. We test the algorithm in ideal conditions and in real life examples including tuning of the event generators Herwig 7 and Pythia 8 for LEP observables. Further, we tune parts of the Herwig 7 event generator with the Lund string model.
hep-phhep-exEPJC(2020)·27 citations
09*
Absorption of Fermionic Dark Matter by Nuclear Targets
Jeff A. Dror🇺🇸 · Gilly Elor🇺🇸 · Robert McGehee🇺🇸
Absorption of fermionic dark matter leads to a range of distinct and novel signatures at dark matter direct detection and neutrino experiments. We study the possible signals from fermionic absorption by nuclear targets, which we divide into two classes of four Fermi operators: neutral and charged current. In the neutral current signal, dark matter is absorbed by a target nucleus and a neutrino is emitted. This results in a characteristically different nuclear recoil energy spectrum from that of elastic scattering. The charged current channel leads to induced $β$ decays in isotopes which are stable in vacuum as well as shifts of the kinematic endpoint of $β$ spectra in unstable isotopes. To confirm the possibility of observing these signals in light of other constraints, we introduce UV completions of example higher dimensional operators that lead to fermionic absorption signals and study their phenomenology. Most prominently, dark matter which exhibits fermionic absorption signals is necessarily unstable leading to stringent bounds from indirect detection searches. Nevertheless, we find a large viable parameter space in which dark matter is sufficiently long lived and detectable in current and future experiments.
hep-phastro-ph.COhep-exJHEP(2020)·91 citations
10*
SimpleBounce : a simple package for the false vacuum decay
Ryosuke Sato🇩🇪
We present SimpleBounce, a C++ package for finding the bounce solution for the false vacuum decay. This package is based on a flow equation which is proposed by the author and solves Coleman-Glaser-Martin's reduced problem: the minimization problem of the kinetic energy while fixing the potential energy. The bounce configuration is obtained by a scale transformation of the solution of this problem. For models with 1--8 scalar field(s), the bounce action can be calculated with O(0.1) % accuracy in O(0.1) s. This package is available at https://github.com/rsato64/SimpleBounce.
hep-phastro-ph.COhep-thComput.Phys.Commun.(2021)·44 citations
11*
On the relation between Migdal effect and dark matter-electron scattering in isolated atoms and semiconductors
Rouven Essig🇺🇸 · Josef Pradler🇦🇹 · Mukul Sholapurkar🇺🇸 · Tien-Tien Yu🇺🇸
A key strategy for the direct detection of sub-GeV dark matter is to search for small ionization signals. These can arise from dark matter-electron scattering or when the dark matter-nucleus scattering process is accompanied by a "Migdal" electron. We show that the theoretical descriptions of both processes are closely related, which allows for a principal mapping between dark matter-electron and dark matter-nucleus scattering rates once the dark matter interactions with matter are specified. We explore this parametric relationship for noble-liquid targets and, for the first time, provide an estimate of the "Migdal" ionization rate in semiconductors that is based on evaluating a crystal form factor that accounts for the semiconductor band structure. We also present new dark-matter-nucleus scattering limits down to dark matter masses of 500 keV using published data from XENON10, XENON100, and a SENSEI prototype Skipper-CCD. For a dark photon mediator, the dark matter-electron scattering rates dominate over the Migdal rates for dark matter masses below 100 MeV. We also provide projections for proposed experiments with xenon and silicon targets.
hep-phPRL(2020)·160 citations
12*
Parton Physics on a Quantum Computer
Henry Lamm🇺🇸 · Scott Lawrence🇺🇸 · Yukari Yamauchi (for the NuQS Collaboration)🇺🇸
Parton distribution functions and hadronic tensors may be computed on a universal quantum computer without many of the complexities that apply to Euclidean lattice calculations. We detail algorithms for computing parton distribution functions and the hadronic tensor in the Thirring model. Their generalization to QCD is discussed, with the conclusion that the parton distribution function is best obtained by fitting the hadronic tensor, rather than direct calculation. As a side effect of this method, we find that lepton-hadron cross sections may be computed relatively cheaply. Finally, we estimate the computational cost of performing such a calculation on a digital quantum computer, including the cost of state preparation, for physically relevant parameters.
↳ hep-lathep-phnucl-thquant-phPRResearch(2020)·129 citations
13*
Comprehensive study of mass modifications of light mesons in nuclear matter in the three-flavor extended Linear Sigma Model
Daiki Suenaga🇨🇳 · Phillip Lakaschus🇩🇪
We present a comprehensive study of mass modifications of scalar, pseudo-scalar, vector, and axial-vector mesons in nuclear matter using the three-flavor extended Linear Sigma Model (eLSM) and the two-flavor Parity Doublet Model (PDM). The meson masses in nuclear matter are determined by calculating the one-loop nucleon corrections to the meson mean fields. As a result, we find all spin- $0$ meson masses except those of the pion, kaon, and the lightest scalar-isoscalar mesons decrease at finite baryon density. For spin- $1$ mesons, masses of all axial-vector mesons decrease in medium, and the density dependences of the $ρ$ and $ω$ meson masses strongly depend on the value of chiral invariant mass ( $M_{0}$ ). Also, our results suggest $M_{0} \approx 0.8 GeV$ is preferable.
↳ nucl-thhep-phPRC(2020)·16 citations
14*
Boson pair production in arbitrarily polarized electric fields
Z. L. Li🇨🇳 · B. S. Xie🇨🇳 · Y. J. Li🇨🇳
The momentum spectrum and number density of created bosons for two types of arbitrarily polarized electric fields are calculated and compared with those of created fermions, employing the equal-time Feshbach-Villars-Heisenberg-Wigner formalism which is confirmed that for an uniform and time-varying electric field it is completely equivalent to the quantum Vlasov equation in scalar QED. For an elliptically polarized field, it is found that the number density of created bosons is a square root of the number density of spin-up electrons times that of spin-down ones for a circularly polarized multicycle field. Moreover, the degree of spin polarization roughly grows as the Keldysh adiabaticity parameter increases for arbitrarily polarized multicycle fields. For a field constituted of two circularly polarized fields with a time delay, it is shown that momentum vortices also exist in boson pair creation and are induced only by the orbital angular momentum of particles. However, the vortices can reproduce the quantum statistic effect due to the effect of spin of particles. These results further deepen the understanding of some significant signatures in pair production.
↳ quant-phhep-phPRD(2019)·23 citations
15*
Possible Formation of QGP-droplets in Proton-Proton Collisions at the CERN Large Hadron Collider
Raghunath Sahoo🇮🇳
Proton-proton (pp) collisions have been traditionally used as a baseline measurement in the search for a deconfined state of matter in heavy-ion collisions at ultrarelativistic energies. The unprecedented collision energies that are available at the Large Hadron Collider (LHC) at the European Laboratory for Nuclear Research (CERN) have illuminated new challenges in understanding the possible formation of droplets of this deconfined matter of partonic degrees of freedom in hadronic collisions, especially in high-multiplicity events. Enhancement of multi-strange particles compared to pions, degree of collectivity, comparable freeze-out temperature with heavy-ion collisions, observation of a long-range ridge-like structure for high-multiplicity events are some of the experimental observations in this direction. In this article, we discuss some of the experimental observables and outline new theoretical directions to understand the possibilities of exploring the formation of QGP-droplets in pp collisions at the LHC.
↳ nucl-exhep-exhep-phnucl-thAAPPS Bull.(2019)·53 citations
16*
Neutrino halo effect on collective neutrino oscillation in iron core-collapse supernova model of a 9.6 $M_{⊙}$ star
Masamichi Zaizen🇯🇵 · John F. Cherry🇺🇸 · Tomoya Takiwaki🇯🇵 · Shunsaku Horiuchi🇺🇸 · Kei Kotake🇯🇵 · Hideyuki Umeda🇯🇵 · Takashi Yoshida🇯🇵
We extend the multi-angle computational framework and investigate the time evolution of the neutrino halo on collective neutrino oscillation in the core collapse of an iron core progenitor. We find that in the case of the $9.6 M_{⊙}$ progenitor adopted in this work, there are windows of time when the effects of neutrino halo and collective neutrino oscillation are not simultaneously large. Inside the shock, the impact of the inward-scattered halo neutrino cannot in general be neglected compared to the outward-propagating neutrino flux. However, during early epochs, collective neutrino oscillation is effectively shut down by multi-angle matter suppression. During the intermediate epoch, collective neutrino oscillation is not suppressed, but its onset radius is beyond the still relatively small explosion shock front where the halo is prominent. We also find in the case of the $9.6 M_{⊙}$ progenitor the halo neutrinos induce a delay in the onset of collective neutrino oscillations. This causes novel flavor conversions which sharpen collective neutrino oscillation spectral features. We predict that the inclusion of neutrino halo effects makes neutrino signals that are more clearly distinct from thermal emission that when halo neutrinos are omitted.
↳ astro-ph.HEhep-phJCAP(2020)·30 citations
17*
Moments of nucleon generalized parton distributions from lattice QCD simulations at physical pion mass
C. Alexandrou (Univ. of Cyprus & Cyprus Inst.)🇨🇾 · S. Bacchio (Cyprus Inst.)🇨🇾 · M. Constantinou (Temple Univ.)🇺🇸 · P. Dimopoulos (Rome Tor Vergata)🇮🇹 · J. Finkenrath (Cyprus Inst.)🇨🇾 · R. Frezzotti (Rome Tor Vergata)🇮🇹 · K. Hadjiyiannakou (Cyprus Inst.)🇨🇾 · K. Jansen (DESY-Zeuthen)🇩🇪 · B. Kostrzewa (Univ. of Bonn)🇩🇪 · G. Koutsou (Cyprus Inst.)🇨🇾 · C. Lauer (Temple Univ. & Argonne National Lab.)🇺🇸 · C. Urbach (Univ. of Bonn)🇩🇪
We present results for the moments of nucleon isovector vector and axial generalised parton distribution functions computed within lattice QCD. Three ensembles of maximally twisted mass clover-improved fermions simulated with a physical value of the pion mass are analyzed. Two of these ensembles are generated using two degenerate light quarks. A third ensemble is used having, in addition to the light quarks, strange and charm quarks in the sea. A careful analysis of the convergence to the ground state is carried out that is shown to be essential for extracting the correct nucleon matrix elements. This allows a controlled determination of the unpolarised, helicity and tensor second Mellin moments. The vector and axial-vector generalised form factors are also computed as a function of the momentum transfer square up to about 1 GeV $^{2}$ . The three ensembles allow us to check for unquenching effects and to assess lattice finite volume effects.
↳ hep-lathep-exhep-phnucl-thPRD(2020)·98 citations
18*
Characterizing the Nature of the Unresolved Point Sources in the Galactic Center
Laura J. Chang🇺🇸 · Siddharth Mishra-Sharma🇺🇸 · Mariangela Lisanti🇺🇸 · Malte Buschmann🇺🇸 · Nicholas L. Rodd🇺🇸 · Benjamin R. Safdi🇺🇸
The Galactic Center Excess (GCE) of GeV gamma rays can be explained as a signal of annihilating dark matter or of emission from unresolved astrophysical sources, such as millisecond pulsars. Evidence for the latter is provided by a statistical procedure---referred to as Non-Poissonian Template Fitting (NPTF)---that distinguishes the smooth distribution of photons expected for dark matter annihilation from a "clumpy" photon distribution expected for point sources. In this paper, we perform an extensive study of the NPTF on simulated data, exploring its ability to recover the flux and luminosity function of unresolved sources at the Galactic Center. When astrophysical background emission is perfectly modeled, we find that the NPTF successfully distinguishes between the dark matter and point source hypotheses when either component makes up the entirety of the GCE. When the GCE is a mixture of dark matter and point sources, the NPTF may fail to reconstruct the correct contribution of each component. We further study the impact of mismodeling the Galactic diffuse backgrounds, finding that while a dark matter signal could be attributed to point sources in some outlying cases for the scenarios we consider, the significance of a true point source signal remains robust. Our work enables us to comment on a recent study by Leane and Slatyer (2019) that questions prior NPTF conclusions because the method does not recover an artificial dark matter signal injected on actual Fermi data. We demonstrate that the failure of the NPTF to extract an artificial dark matter signal can be natural when point sources are present in the data---with the effect further exacerbated by the presence of diffuse mismodeling---and does not on its own invalidate the conclusions of the NPTF analysis in the Inner Galaxy.
↳ astro-ph.COastro-ph.HEhep-phPRD(2020)·66 citations
19*
Axions as a probe of solar metals
Joerg Jaeckel🇩🇪 · Lennert J. Thormaehlen🇩🇪
If axions or axion-like particles exist and are detected, they will not only extend the standard model of particle physics but will also open a new way to probe their sources. Axion helioscopes aim to detect axions which are produced in the core of the sun. Their spectrum contains information about the solar interior and could in principle help to solve the conflict between high and low metallicity solar models. Using the planned International Axion Observatory (IAXO) as an example, we show that helioscopes could measure the strength of characteristic emission peaks caused by the presence of heavier elements with good precision. In order to determine unambiguously the elemental abundances from this information, an improved modelling of the states of atoms inside the solar plasma is required.
↳ astro-ph.SRhep-phPRD(2019)·26 citations
20*
Neutrino Emissions from Tidal Disruption Remnants
Kimitake Hayasaki🇰🇷 · Ryo Yamazaki🇯🇵
We study high-energy neutrino emissions from tidal disruption remnants (TDRs) around supermassive black holes. The neutrinos are produced by the decay of charged pions originating in ultrarelativistic protons that are accelerated there. In the standard theory of tidal disruption events (TDEs), there are four distinct phases from debris circularization of stellar debris to super- and sub-Eddington to radiatively inefficient accretion flows (RIAFs). In addition, we consider the magnetically arrested disk (MAD) state in both the super-Eddington accretion and RIAF phases. We find that there are three promising cases to produce neutrino emissions: the super-Eddington accretion phase of the MAD state and the RIAF phases of both the non-MAD and MAD states. In the super-Eddington MAD state, the enhanced magnetic field makes it possible to accelerate the protons to $E_{p, ma x} 0.35 P e V (M_{b} h /1 0^{7.7} M_{⊙})^{41/48}$ with the other given appropriate parameters. The neutrino energy is then $E_{ν, p k} 67 T e V (M_{b} h /1 0^{7.7} M_{⊙})^{41/48}$ at the peak of the energy spectrum. For $M_{b} h ≳ 1 0^{7.7} M_{⊙}$ , the neutrino light curve is proportional to $t^{- 65/24}$ , while it follows the standard $t^{- 5/3}$ decay rate for $M_{b} h < 1 0^{7.7} M_{⊙}$ . In both cases, the large luminosity and characteristic light curves diagnose the super-Eddington MAD state in TDEs. In the RIAF phase of the non-MAD state, we find $E_{p, ma x} 0.45 P e V (M_{b} h /1 0^{7} M_{⊙})^{5/3}$ and $E_{ν, p k} 0.35 P e V (M_{b} h /1 0^{7} M_{⊙})^{5/3}$ , and its light curve is proportional to $t^{- 10/3}$ . This indicates that one can identify whether the existing RIAFs are the TDE origin or not. TDRs are potentially a population of hidden neutrino sources invisible in gamma rays.
↳ astro-ph.HEgr-qchep-ph43 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.