Wed·Jun 23, 2021Wednesday·June 23, 2021

1. 01*

   Quantization of magnetic flux and electron-positron pair creation

   Mehmet Emre Tasgin🇹🇷

   An electron-positron pair ($e^{-}{e}^{+}$) is created in vacuum above a critical electric field strength $E_{crt}$ which is quite large in the laboratory scale. The photon, thus the field, annihilates in the pair creation process. Here, we question if the pair creation (at $E=E_{crt}$) introduces a boundary condition in the electromagnetic state, e.g., similar to the one in angular or linear momentum. We show that introduction of such a reasonable condition yields approximately the well-known magnetic flux quanta which normally one obtains using different arguments.

   hep-phquant-ph0 citations
2. 02*

   The strong CP problem solved by itself due to long-distance vacuum effects

   Y. Nakamura🇯🇵 · G. Schierholz🇩🇪

   The vacuum of quantum chromodynamics has an incredibly rich structure at the nonperturbative level, which is intimately connected with the topology of gauge fields, and put to a test by the strong CP problem. We investigate the long-distance properties of the theory in the presence of the topological $\theta$ term. This is done on the lattice, using the gradient flow to isolate the long-distance modes in the functional integral measure and tracing it over successive length scales. The key point is that the vacuum splits into disconnected topological sectors with markedly different physical characteristics, which gives rise to a nontrivial behavior depending on $\theta$. We find that the color fields produced by quarks and gluons are screened, and confinement is lost, for bare vacuum angles $|\theta |>0$, thus providing a natural solution of the strong CP problem. The renormalized vacuum angle $\theta$ is found to flow to zero in the infrared limit, leading to a self-consistent solution within QCD.

   hep-phhep-lathep-thnucl-thNPB(2023)·40 citations
3. 03*

   Model dependence of the polarization asymmetries in weak pion production off the nucleon

   Krzysztof M. Graczyk🇵🇱 · Beata E. Kowal🇵🇱

   The work presents the studies of the polarization observables in the single pion production (SPP) induced by the interaction of the muon neutrino (antineutrino) with nucleons. The SPP cross-sections and spin asymmetries are computed within two phenomenological models. One is basing on the nonlinear sigma model \cite{Hernandez:2007qq}; the other has origin in linear sigma model~\cite{Fogli:1979cz}. Firstly, we show that the final nucleon polarization and target spin asymmetries are good observables to obtain information about the $C_5^A$ axial form factor. Secondly, we demonstrate that the nucleon polarization and the target spin asymmetries are sensitive to the relative phase between resonance and nonresonance amplitudes. We conclude that the polarization of the final nucleon and the target spin asymmetry are promising observables for testing SPP models, including studies of the axial content of $\Delta (1232)$ resonance and unitarization procedures.

   hep-phhep-exnucl-exnucl-thPRD(2021)·6 citations
4. 04*

   Hidden charm pentaquark with strangeness $P_{cs}^{\ast }(4739)$ as a ${\Sigma }_c\bar{D}\bar{K}$ bound state

   Tian-Wei Wu🇨🇳 · Ya-Wen Pan🇨🇳 · Ming-Zhu Liu🇨🇳 · Jun-Xu Lu🇨🇳 · Li-Sheng Geng🇨🇳 · Xiao-Hai Liu🇨🇳

   Motivated by the recent discovery of the first hidden charm pentaquark state with strangeness $P_{cs}(4459)$ by the LHCb Collaboration, we study the likely existence of a three-body ${\Sigma }_c\bar{D}\bar{K}$ bound state, which shares the same minimal quark content as $P_{cs}(4459)$. The ${\Sigma }_c\bar{D}$ and $DK$ interactions are determined by reproducing $P_c(4312)$ and $D_{s0}^{\ast }(2317)$ as ${\Sigma }_c\bar{D}$ and $\bar{D}\bar{K}$ molecules, respectively, while the ${\Sigma }_c\bar{K}$ interaction is constrained by chiral effective theory. We indeed find a three-body bound state by solving the Schrödinger equation using the Gaussian Expansion Method, which can be viewed as an excited hidden charm pentaquark state with strangeness, $P_{cs}^{\ast }(4739)$, with $I(J^P)=1(1/2^{+})$ and a binding energy of $77.8_{-10.3}^{+25}$ MeV. We further study its strong decays via triangle diagrams and show that its partial decay widths into $D{\Xi }_c^{\prime }$ and $D_s^{\ast }{\Sigma }_c$ are of a few ten's MeV, with the former being dominant.

   hep-phhep-exhep-latPRD(2021)·14 citations
5. 05*

   DPS mechanism for associated $c\bar{c}{l}^{+}{l}^{-}$ production in $AA$ UPCs as a probe for photon density inside the nucleus

   Edgar Huayra🇧🇷 · Emmanuel G. de Oliveira🇧🇷 · Roman Pasechnik🇸🇪 · Bruna O. Stahlhöfer🇧🇷

   We discuss the associated $c\bar{c}$ and $l^{+}{l}^{-}$ pairs production in ultraperipheral heavy-ion collisions at high energies. Such a channel provides a novel probe for double-parton scattering (DPS) at small $x$ enabling one to probe the photon density inside the nucleus. We have derived an analog of the standard central $pp$ pocket formula and studied the kinematical dependence of the effective cross section. Taking into account both elastic and non-elastic contributions, we have shown predictions for the DPS $c\bar{c}{l}^{+}{l}^{-}$ production cross section differential in charm quark rapidity and dilepton invariant mass and rapidity for LHC and a future collider.

   hep-phPRD(2021)·6 citations
6. 06*

   Symmetry Finder: A method for hunting symmetry in neutrino oscillation

   Hisakazu Minakata🇺🇸

   Symmetry in neutrino oscillation serves for a better understanding of the physical properties of the phenomenon. We present a systematic way of finding symmetry in neutrino oscillation, which we call Symmetry Finder (SF). By extending the known framework in vacuum into a matter environment, we derive the SF equation, a powerful machinery for identifying symmetry in the system. After learning lessons on symmetry in the Zaglauer-Schwarzer system with a matter equivalent of the vacuum symmetry, we apply the SF method to the Denton et al. (DMP) perturbation theory to first order. We show that the method is so powerful that we uncover the eight reparametrization symmetries with the $1\leftrightarrow 2$ state exchange in DMP, denoted as IA, IB, $\cdot \cdot \cdot$, IVB, all new except for IA. The transformations consist of the both fundamental and dynamical variables, indicating their equal importance. It is also shown that all the symmetries discussed in this paper can be understood as the Hamiltonian symmetries, which ensures their all-order validity and applicability to varying density matter.

   hep-phPRD(2021)·9 citations
7. 07*

   Balancing asymmetric dark matter with baryon asymmetry and dilution of frozen dark matter by sphaleron transition

   Arnab Chaudhuri🇷🇺 · Maxim Yu. Khlopov🇷🇺

   In this paper we study the effect of electroweak sphaleron transition or electroweak phase transition (EWPT) in balancing baryon excess to the excess stable quarks of $4^{th}$ generation. Considering the conservation of all quantum number and charges, sphaleron transition between between baryons, leptons and $4^{th}$ family of leptons and quarks is possible. We have tried to established a possible definite relationship between the value and sign of the $4^{th}$ family excess relative to baryon asymmetry under the framework of second order EWPT. In passing by we show the small, yet negligible dilution in the pre-existing dark matter density due the sphaleron transition.

   hep-phastro-ph.COUniverse(2021)·9 citations
8. 08*

   Flavor mixing and CP violation from the interplay of $S_4$ modular group and gCP

   Bu-Yao Qu🇨🇳 · Xiang-Gan Liu🇨🇳 · Ping-Tao Chen🇨🇳 · Gui-Jun Ding🇨🇳

   We have performed a systematical analysis of lepton and quark masses models based on ${\Gamma }_4\cong S_4$ modular symmetry with gCP symmetry. We have considered both cases that neutrinos are Majorana particles and Dirac particles. All possible nontrivial representation assignments of matter fields are considered, and the most general form of fermion mass matrices are given. The phenomenologically viable models with the lowest number of free parameters together with the results of fit are presented. We find out nine lepton models with seven real free parameters including the real and imaginary parts of modulus for Majorana neutrinos, which can accommodate the lepton masses and neutrino oscillation data. The prediction for leptogenesis is studied in an example lepton model. The observed baryon asymmetry as well as lepton masses and mixing angles can be explained. For Dirac neutrinos, four lepton models with five real free couplings are compatible with experimental data. Ten quark models containing seven couplings are found to be able to accommodate the hierarchical quark masses and mixing angles and CP violation phase. Furthermore, the $S_4$ modular symmetry can provide a unified description of lepton and quark flavor structure, and a benchmark model is presented.

   hep-phPRD(2021)·49 citations
9. 09*

   Medium effects in supernovae constraints on light mediators

   David G. Cerdeño🇪🇸 · Marina Cermeño🇧🇪 · M. Ángeles Pérez-García🇪🇸 · Elliott Reid🇬🇧

   In this article, we reevaluate supernovae (SN) constraints on the diffusion time of neutrinos for a family of extensions of the Standard Model that incorporate new light scalar and vector mediators. We compute the neutrino mean free path, taking into account medium effects in the neutrino-nucleon scattering cross-section, and a radial dependence of the density, energy, and temperature inside the proto-neutron star to determine the coupling strengths compatible with SN1987A constraints on the time duration signal of diffusing neutrinos. We show that medium effects can induce an order of magnitude enhancement in the neutrino mean free path with respect to the vacuum calculation. The increase is more significant when new physics terms dominate over the Standard Model contribution (that is, for small mediator mass and large couplings). Finally, we interpret these results as bounds on the parameter space of a vector $U(1{)}_{B-L}$ model and scalar lepton number conserving and lepton number violating scenarios, improving on previous results in the literature where medium effects were ignored. We show that SN constraints on the neutrino diffusion time lie within regions of the parameter space that are already ruled out by other experimental constraints. We also comment on potential limits due to changes in the SN equation of state or right-handed neutrino free-streaming, but argue that detailed numerical simulations are needed to improve the reliability of these limits.

   hep-phastro-ph.COPRD(2021)·16 citations
10. 10*

    Inferring the nature of active neutrinos: Dirac or Majorana?

    C. S. Kim🇰🇷 · M. V. N. Murthy🇮🇳 · Dibyakrupa Sahoo🇮🇳

    The nature of a neutrino, whether it is a Dirac type or Majorana type, may be comprehensively probed using their quantum statistical properties. If the neutrino is a Majorana fermion, then by definition it is identical and indistinguishable from the corresponding antineutrino. When a Majorana neutrino and antineutrino are pair produced, the corresponding state has to obey the Pauli principle unlike in the Dirac case. We use this property to distinguish between the two cases using the process $B^0\to {\mu }^{-}{\mu }^{+}{\nu }_{\mu }{\bar{\nu }}_{\mu }$. We show that the two cases differ dramatically in a special kinematic scenario where, in the rest frame of the parent $B$ meson, the muons fly away back-to-back (i.e. fly with 3-momenta of equal magnitudes but opposite directions), and so do the neutrino and antineutrino. Unlike any other scenario, we know the energies and magnitudes of $3$-momenta of both the neutrino and the antineutrino in this back-to-back configuration without even directly measuring them. This provides a way of avoiding the constraint imposed by the `practical Dirac-Majorana confusion theorem', as one need not fully integrate over neutrino and antineutrino in this case. As a true signature of the universal principle of quantum statistics which does not depend on the size of the mass of the particle but its spin, the difference between Dirac and Majorana cases in this special kinematic configuration does survive independent of the neutrino mass as long as neutrino mass is nonzero. The analysis presented here is applicable immediately to several other processes with the same final state as in the case of $B^0$ decay without any major change.

    hep-phPRD(2022)·25 citations
11. 11*

    What do DVCS data tell us about TCS observables?

    O.~Grocholski🇵🇱 · H.~Moutarde🇫🇷 · B. Pire🇫🇷 · P. Sznajder🇵🇱 · J. Wagner🇵🇱

    Deeply virtual Compton scattering (DVCS) and timelike Compton scattering (TCS) leading twist amplitudes are intimately related thanks to their analytic properties as a function of $Q^2$. We exploit this feature to use Compton form factors previously extracted from available DVCS data and derive data-driven predictions for TCS observables to be measured in near future experiments. Our results quantitatively illustrate the complementarity of DVCS and TCS experiments.

    hep-phhep-exnucl-exSciPost Phys.Proc.(2022)·0 citations
12. 12*

    Theory requirements for SM Higgs and EW precision physics at the FCC-ee

    Sven Heinemeyer🇪🇸 · Stanislaw Jadach🇵🇱 · Jürgen Reuter🇩🇪

    High precision experimental measurements of the properties of the Higgs boson at $\sim$ 125 GeV as well as electroweak precision observables such as the W -boson mass or the effective weak leptonic mixing angle are expected at future $e^{+}{e}^{-}$ colliders such as the FCC-ee. This high anticipated precision has to be matched with theory predictions for the measured quantities at the same level of accuracy. We briefly summarize the status of these predictions within the Standard Model (SM) and of the tools that are used for their determination. We outline how the theory predictions will have to be improved in order to reach the required accuracy, and also comment on the simulation frameworks for the Higgs and EW precision program.

    hep-phhep-exEur.Phys.J.Plus(2021)·32 citations
13. 13*

    Doubly Heavy Tetraquark Resonant States

    Qi Meng🇨🇳 · Masayasu Harada🇯🇵 · Emiko Hiyama🇯🇵 · Atsushi Hosaka🇯🇵 · Makoto Oka🇯🇵

    Spectrum of the doubly heavy tetraquarks, $bb\bar{q}\bar{q}$, is studied in a constituent quark model. Four-body problem is solved in a variational method where the real scaling technique is used to identify resonant states above the fall-apart decay thresholds. In addition to the two bound states that were reported in the previous study we have found several narrow resonant states above the $B{B}^{\ast }$ and $B^{\ast }{B}^{\ast }$ thresholds. Their structures are studied and are interpreted by the quark dynamics. A narrow resonance with spin-parity $J^P=1^{+}$ is found to be a mixed state of a compact tetraquark and a $B^{\ast }{B}^{\ast }$ scattering state. This is driven by a strong color Coulombic attraction between the $bb$ quarks. Negative-parity excited resonances with $J^P=0^{-}$, $1^{-}$ and $2^{-}$ form a triplet under the heavy-quark spin symmetry. It turns out that they share a similar structure to the $\lambda$-mode of a singly heavy baryon as a result of the strongly attractive correlation for the doubly heavy diquark.

    hep-phnucl-thPLB(2022)·40 citations
14. 14*

    Two-component scalar dark matter in $Z_{2n}$ scenarios

    Carlos E. Yaguna🇨🇴 · Óscar Zapata🇨🇴

    In multi-component scalar dark matter scenarios, a single $Z_N$ ($N\ge 4$) symmetry may account for the stability of different dark matter particles. Here we study the case where $N$ is even ($N=2n$) and two species, a complex scalar and a real scalar, contribute to the observed dark matter density. We perform a phenomenological analysis of three scenarios based on the $Z_4$ and $Z_6$ symmetries, characterizing their viable parameter spaces and analyzing their detection prospects. Our results show that, thanks to the new interactions allowed by the $Z_{2n}$ symmetry, current experimental constraints can be satisfied over a wider range of dark matter masses, and that these scenarios may lead to observable signals in direct detection experiments. Finally, we argue that these three scenarios serve as prototypes for other two-component $Z_{2n}$ models with one complex and one real dark matter particle.

    hep-phJHEP(2021)·26 citations
15. 15*

    Mixed strong$-$electroweak corrections to the Drell$-$Yan process

    Roberto Bonciani🇮🇹 · Luca Buonocore🇨🇭 · Massimiliano Grazzini🇨🇭 · Stefan Kallweit🇮🇹 · Narayan Rana🇮🇹 · Francesco Tramontano🇮🇹 · Alessandro Vicini🇮🇹

    We report on the first complete computation of the mixed QCD$-$electroweak (EW) corrections to the neutral-current Drell$-$Yan process. Superseding previously applied approximations, our calculation provides the first result at this order that is valid in the entire range of dilepton invariant masses. The two-loop virtual contribution is computed by using semi-analytical techniques, overcoming the technical problems in the evaluation of the relevant master integrals. The cancellation of soft and collinear singularities is achieved by a formulation of the $q_T$ subtraction formalism valid in presence of charged massive particles in the final state. We present numerical results for the fiducial cross section and selected kinematical distributions. At large values of the lepton $p_T$ the mixed QCD$-$EW corrections are negative and increase in size, to about $-15\%$ with respect to the next-to-leading-order QCD result at $p_T=500$GeV. Up to dilepton invariant masses of 1 TeV the computed corrections amount to about $-1.5\%$ with respect to the next-to-leading-order QCD result.

    hep-phPRL(2022)·99 citations
16. 16*

    Current bounds on the Type-Z $Z_3$ three Higgs doublet model

    Rafael Boto🇵🇹 · Jorge C. Romão🇵🇹 · João P. Silva🇵🇹

    Type-Z models, where charged leptons, up type quarks, and down type quarks each couple to a different scalar, are only possible when there are three or more Higgs doublets. We consider the Type-Z three Higgs doublet model imposed by a softly broken $Z_3$ symmetry. We take into account all theoretical and experimental constraints, highlighting the importance of perturbative unitarity and bounded from below conditions that we develop here, and which have a strong impact on $B\to X_s\gamma$. Since there can be cancellations between the two charged Higgs in $B\to X_s\gamma$ (and in $h\to \gamma \gamma$), the lower bounds obtained on the charged Higgs masses are alleviated. We also discuss in detail the important physical differences between exact alignment and approximate alignment, and present some useful benchmark points.

    hep-phPRD(2021)·32 citations
17. 17*

    Phenomenological mass model for exotic hadrons and predictions for masses of non-strange dibaryons as hexaquarks

    Christoffer Beiming🇸🇪 · Jesper Grönroos🇸🇪 · Tommy Ohlsson🇸🇪

    We investigate the mass spectra of exotic hadrons known as hexaquarks in the form of dibaryons. We use a phenomenological model based on an extended version of the Gürsey-Radicati mass formula for hadrons to include non-charmed baryons, charmed baryons, and non-strange dibaryons to be able to predict masses of potential dibaryon states. We perform six numerical fits of this model to input data for three different sets of masses of baryons and dibaryons. We find that the model can fit some of the data sets well, especially the sets including charmed baryons and non-strange dibaryons, and observe that the predicted mass of one of the dibaryons is close to the measured mass of the observed hexaquark candidate $d^{\ast }(2380)$ reported by the WASA-at-COSY experiment. The predicted mass of the deuteron is slightly larger than its measured mass. Finally, for the data sets including charmed baryon and non-strange dibaryon masses, we find that the predicted masses of potential dibaryon states are all in the range from 1900 MeV to 3700 MeV.

    hep-phhep-exnucl-exnucl-thNPB(2022)·9 citations
18. 18*

    Towards baryogenesis via absorption from Primordial Black Holes

    Antonio Ambrosone🇮🇹 · Roberta Calabrese🇮🇹 · Damiano F. G. Fiorillo🇮🇹 · Gennaro Miele🇮🇹 · Stefano Morisi🇮🇹

    Recently Dolgov and Pozdnyakov proposed a new baryogenesis mechanism in which baryon asymmetry is produced without violating baryon number at the Lagrangian level. In this scenario, baryon asymmetry is generated by absorption of a new particle X carrying baryon number onto Primordial Black Holes (PBHs). Assuming CP-violation, the particle X is absorbed at a different rate than the antiparticle $\bar{X}$, producing an asymmetry in the baryonic number. We independently test this scenario, finding that it suffers from two fundamental issues.\\ At the phenomenological level, strong absorption by PBHs initially increases the baryon asymmetry. However, at later times such asymmetry is completely absorbed by PBHs. In order to overcome this issue, we account for PBH evaporation, which provides a natural way of halting the absorption while keeping a finite baryon asymmetry. We provide a systematic study of the parameter space, identifying the regions leading to the production of the baryon asymmetry without violating the known constraints on PBHs concentration. At the theoretical level, a model realizing the CP-violation postulated in this scenario is difficult to realize. We show, by implementing a minimal model, that the framework proposed in the original work in order to produce CP-violation, even if qualitatively correct, is quantitatively in disagreement with the observed baryon asymmetry, namely this mechanism produces only a fraction of the total baryon asymmetry.

    hep-phastro-ph.HEgr-qchep-ex+1PRD(2022)·31 citations
19. 19*

    Cosmology meets functional QCD: First-order cosmic QCD transition induced by large lepton asymmetries

    Fei Gao🇩🇪 · Isabel M. Oldengott🇧🇪

    The lepton flavour asymmetries of the Universe are observationally almost unconstrained before the onset of neutrino oscillations. We calculate the cosmic trajectory during the cosmic QCD epoch in the presence of large lepton flavour asymmetries. By including QCD thermodynamic quantities derived from functional QCD methods in our calculation our work reveals for the first time the possibility of a first-order cosmic QCD transition. We specify the required values of the lepton flavour asymmetries for which a first-order transition occurs for a number of different benchmark scenarios.

    hep-phastro-ph.COhep-thPRL(2022)·47 citations
20. 20*

    Determining the jet transport coefficient $\hat{q}$ of the quark-gluon plasma using Bayesian parameter estimation

    J. Mulligan🇺🇸 · A. Angerami🇺🇸 · R. Arora🇺🇸 · S. A. Bass🇺🇸 · S. Cao🇺🇸 · Y. Chen🇺🇸 · J. Coleman🇺🇸 · L. Cunqueiro🇺🇸 · T. Dai🇺🇸 · L. Du🇺🇸 · R. Ehlers🇺🇸 · H. Elfner🇩🇪 and 37 other authors

    We present a new determination of $\hat{q}$, the jet transport coefficient of the quark-gluon plasma. Using the JETSCAPE framework, we use Bayesian parameter estimation to constrain the dependence of $\hat{q}$ on the jet energy, virtuality, and medium temperature from experimental measurements of inclusive hadron suppression in Au-Au collisions at RHIC and Pb-Pb collisions at the LHC. These results are based on a multi-stage theoretical approach to in-medium jet evolution with the MATTER and LBT jet quenching models. The functional dependence of $\hat{q}$ on jet energy, virtuality, and medium temperature is based on a perturbative picture of in-medium scattering, with components reflecting the different regimes of applicability of MATTER and LBT. The correlation of experimental systematic uncertainties is accounted for in the parameter extraction. These results provide state-of-the-art constraints on $\hat{q}$ and lay the groundwork to extract additional properties of the quark-gluon plasma from jet measurements in heavy-ion collisions.

    ↳ nucl-thhep-phnucl-ex2 citations
21. 21*

    The Weak Lensing Radial Acceleration Relation: Constraining Modified Gravity and Cold Dark Matter theories with KiDS-1000

    Margot M. Brouwer🇳🇱 · Kyle A. Oman🇳🇱 · Edwin A. Valentijn🇳🇱 · Maciej Bilicki🇵🇱 · Catherine Heymans🇬🇧 · Henk Hoekstra🇳🇱 · Nicola R. Napolitano🇨🇳 · Nivya Roy🇨🇦 · Crescenzo Tortora🇮🇹 · Angus H. Wright🇩🇪 · Marika Asgari🇬🇧 · Jan Luca van den Busch and 13 other authors

    We present measurements of the radial gravitational acceleration around isolated galaxies, comparing the expected gravitational acceleration given the baryonic matter with the observed gravitational acceleration, using weak lensing measurements from the fourth data release of the Kilo-Degree Survey. These measurements extend the radial acceleration relation (RAR) by 2 decades into the low-acceleration regime beyond the outskirts of the observable galaxy. We compare our RAR measurements to the predictions of two modified gravity (MG) theories: MOND and Verlinde's emergent gravity. We find that the measured RAR agrees well with the MG predictions. In addition, we find a difference of at least $6\sigma$ between the RARs of early- and late-type galaxies (split by Sérsic index and $u-r$ colour) with the same stellar mass. Current MG theories involve a gravity modification that is independent of other galaxy properties, which would be unable to explain this behaviour. The difference might be explained if only the early-type galaxies have significant ($M_{gas}\approx M_{\ast }$) circumgalactic gaseous haloes. The observed behaviour is also expected in $\Lambda$CDM models where the galaxy-to-halo mass relation depends on the galaxy formation history. We find that MICE, a $\Lambda$CDM simulation with hybrid halo occupation distribution modelling and abundance matching, reproduces the observed RAR but significantly differs from BAHAMAS, a hydrodynamical cosmological galaxy formation simulation. Our results are sensitive to the amount of circumgalactic gas; current observational constraints indicate that the resulting corrections are likely moderate. Measurements of the lensing RAR with future cosmological surveys will be able to further distinguish between MG and $\Lambda$CDM models if systematic uncertainties in the baryonic mass distribution around galaxies are reduced.

    ↳ astro-ph.GAastro-ph.COhep-phhep-thAstron.Astrophys.(2021)·77 citations
22. 22*

    Diagnosing the Quark-Gluon Plasma

    Berndt Müller🇺🇸

    Brief review of the hadronic probes that are used to diagnose the quark-gluon plasma produced in relativistic heavy ion collisions and interrogate its properties. Emphasis is placed on probes that have significantly impacted our understanding of the nature of the quark-gluon plasma and confirmed its formation.

    ↳ nucl-thhep-ph7 citations
23. 23*

    First experimental search for production of magnetic monopoles via the Schwinger mechanism

    B. Acharya🇬🇧 · J. Alexandre🇬🇧 · P. Benes🇨🇿 · B. Bergmann🇨🇿 · S. Bertolucci🇮🇹 · A. Bevan🇬🇧 · H. Branzas🇷🇴 · P.Burian🇨🇿 · M. Campbell🇨🇭 · Y. M. Cho🇰🇷 · M. de Montigny🇨🇦 · A. De Roeck🇨🇭 and 55 other authors

    Schwinger showed that electrically-charged particles can be produced in a strong electric field by quantum tunnelling through the Coulomb barrier. By electromagnetic duality, if magnetic monopoles (MMs) exist, they would be produced by the same mechanism in a sufficiently strong magnetic field. Unique advantages of the Schwinger mechanism are that its rate can be calculated using semiclassical techniques without relying on perturbation theory, and the finite MM size and strong MM-photon coupling are expected to enhance their production. Pb-Pb heavy-ion collisions at the LHC produce the strongest known magnetic fields in the current Universe, and this article presents the first search for MM production by the Schwinger mechanism. It was conducted by the MoEDAL experiment during the 5.02 TeV/nucleon heavy-ion run at the LHC in November 2018, during which the MoEDAL trapping detectors (MMTs) were exposed to 0.235 nb${}^{-1}$ of Pb-Pb collisions. The MMTs were scanned for the presence of magnetic charge using a SQUID magnetometer. MMs with Dirac charges 1$g_D$ $\le$ $g$ $\le$ 3$g_D$ and masses up to 75 GeV/c${}^2$ were excluded by the analysis. This provides the first lower mass limit for finite-size MMs from a collider search and significantly extends previous mass bounds.

    ↳ hep-exhep-phNature(2022)·97 citations
24. 24*

    The Standard Model Quiver in de Sitter String Compactifications

    Michele Cicoli🇮🇹 · Iñaki García Etxebarria🇬🇧 · Fernando Quevedo🇬🇧 · Andreas Schachner🇬🇧 · Pramod Shukla🇮🇹 · Roberto Valandro🇮🇹

    We argue that the Standard Model quiver can be embedded into compact Calabi-Yau geometries through orientifolded D3-branes at del Pezzo singularities ${\mathrm{dP}}_n$ with $n\ge 5$ in a framework including moduli stabilisation. To illustrate our approach, we explicitly construct a local ${\mathrm{dP}}_5$ model via a combination of Higgsing and orientifolding. This procedure reduces the original ${\mathrm{dP}}_5$ quiver gauge theory to the Left-Right symmetric model with three families of quarks and leptons as well as a Higgs sector to further break the symmetries to the Standard Model gauge group. We embed this local model in a globally consistent Calabi-Yau flux compactification with tadpole and Freed-Witten anomaly cancellations. The model features closed string moduli stabilisation with a de Sitter minimum from T-branes, supersymmetry broken by the Kähler moduli, and the MSSM as the low energy spectrum. We further discuss phenomenological and cosmological implications of this construction.

    ↳ hep-thhep-phJHEP(2021)·70 citations
25. 25*

    Probing Compensated Isocurvature with the 21-cm Signal during Cosmic Dawn

    Selim C. Hotinli🇺🇸 · Thomas Binnie🇬🇧 · Julian B. Muñoz🇺🇸 · Bikash R. Dinda🇮🇳 · Marc Kamionkowski🇺🇸

    Upcoming measurements of the 21-cm line of neutral hydrogen will open a new observational window into the early stages of structure growth, providing a unique opportunity for probing large-scale cosmological signatures using the small-scale signals from the first stars. In this paper we evaluate the detection significance of compensated isocurvature perturbations (CIPs) from observations of the 21-cm hydrogen-line during the cosmic-dawn era. CIPs are modulations of the relative baryon and dark-matter density that leave the total matter density unchanged. We find that, under different assumptions for feedback and foregrounds, the ongoing HERA and upcoming SKA1-low experiments will provide constraints on uncorrelated CIPs at the level of $\sigma (A_{\mathrm{CIP}})=10^{-3}-10^{-4}$, comparable to the sensitivity of upcoming CMB experiments, and potentially exceeding the constraints from cosmic-variance limited BAO surveys.

    ↳ astro-ph.COhep-phPRD(2021)·16 citations
26. 26*

    Classicalization and unitarization of wee partons in QCD and Gravity: The CGC-Black Hole correspondence

    Gia Dvali🇩🇪 · Raju Venugopalan🇺🇸

    We discuss a remarkable correspondence between the description of Black Holes as highly occupied condensates of $N$ weakly interacting gravitons and that of Color Glass Condensates (CGCs) as highly occupied gluon states. In both cases, the dynamics of "wee partons" in Regge asymptotics is controlled by emergent semi-hard scales that lead to perturbative unitarization and classicalization of $2\to N$ particle amplitudes at weak coupling. In particular, they attain a maximal entropy permitted by unitarity, bounded by the inverse coupling $\alpha$ of the respective constituents. Strikingly, this entropy is equal to the area measured in units of the Goldstone constant corresponding to the spontaneous breaking of Poincaré symmetry by the corresponding graviton or gluon condensate. In gravity, the Goldstone constant is the Planck scale, and gives rise to the Bekenstein-Hawking entropy. Likewise, in the CGC, the corresponding Goldstone scale is determined by the onset of gluon screening. We point to further similarities in Black Hole formation, thermalization and decay, to that of the Glasma matter formed from colliding CGCs in ultrarelativistic nuclear collisions, which decays into a Quark-Gluon Plasma.

    ↳ hep-thgr-qchep-phnucl-thPRD(2022)·73 citations
27. 27*

    Entropy Wave Instability in Dirac and Weyl Semimetals

    P. O. Sukhachov🇺🇸 · E. V. Gorbar🇺🇦 · I. A. Shovkovy🇺🇸

    Hydrodynamic instabilities driven by a direct current are analyzed in 2D and 3D relativisticlike systems with the Dyakonov-Shur boundary conditions supplemented by a boundary condition for temperature. Besides the conventional Dyakonov-Shur instability for plasmons, we find an entropy wave instability in both 2D and 3D systems. The entropy wave instability is a manifestation of the relativisticlike nature of electron quasiparticles and a nontrivial role of the energy current in such systems. These two instabilities occur for the opposite directions of fluid flow. While the Dyakonov-Shur instability is characterized by the plasma frequency in 3D and the system size in 2D, the frequency of the entropy wave instability is tunable by the system size and the flow velocity.

    ↳ cond-mat.mes-hallhep-phPRL(2021)·0 citations
28. 28*

    Quantum electrodynamics with self-conjugated equations with spinor wave functions for fermion fields

    V.P.Neznamov · V.E. Shemarulin

    Quantum electrodynamics (QED) with self-conjugated equations with spinor wave functions for fermion fields is considered. In the low order of the perturbation theory, matrix elements of some of QED physical processes are calculated. The final results coincide with cross-sections calculated in the standard QED. The self-energy of an electron and amplitudes of processes associated with determination of the anomalous magnetic moment of an electron and Lamb shift are calculated. These results agree with the results in the standard QED.Distinctive feature of the developed theory is the fact that only states with positive energies are present in the intermediate virtual states in the calculations of the electron self-energy, anomalous magnetic moment of an electron and Lamb shift. Besides, in equations, masses of particle and anti-particles have the opposite signs.

    ↳ physics.gen-phhep-phhep-thInt.J.Mod.Phys.A(2021)·5 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.