Thu·Oct 20, 2022Thursday·October 20, 2022

1. 01*

   Effects of new physics in neutrino propagation

   J. M. Carmona🇪🇸 · J. L. Cortés🇪🇸 · J. J. Relancio🇪🇸 · M. A. Reyes

   In this work we consider the effects of Lorentz Invariance Violation over the observed flux of very high-energy neutrinos. For that, we study the neutrino propagation in a Modified Dispersion Relation scenario with a superluminal velocity. This makes the neutrino unstable and causes a cut-off in the flux of detected neutrinos. Using simple models, one can approximate the location of the cut-off as function of the parameters of new physics and the closest source.

   hep-phastro-ph.HEPoS(2022)·1 citation
2. 02*

   Division algebraic symmetry breaking

   N. Furey🇩🇪 · M.J. Hughes🇩🇪

   Reframing certain well-known particle models in terms of normed division algebras leads to two new results for BSM physics. (1) We identify a sequence of complex structures which induces a cascade of breaking symmetries: Spin(10) $\mapsto$ Pati-Salam $\mapsto$ Left-Right symmetric $\mapsto$ Standard model + B-L (both pre- and post-Higgs-mechanism). These complex structures derive from the octonions, then from the quaternions, then from the complex numbers. (2) We provide, also for the first time we believe, an explicit demonstration of left-right symmetric Higgs representations stemming from quaternionic triality, tri($\mathbb{H}$). Upon the breaking of $su(2{)}_R$, our Higgs reduces to the familiar standard model Higgs.

   hep-phhep-thPLB(2022)·29 citations
3. 03*

   Different Coalescence Sources of Light Nuclei Production in Au-Au Collisions at $\sqrt{s_{NN}}=3$ GeV

   Rui-Qin Wang🇨🇳 · Ji-Peng Lv🇨🇳 · Yan-Hao Li🇨🇳 · Jun Song🇨🇳 · Feng-Lan Shao🇨🇳

   We study the production of light nuclei in the coalescence mechanism in Au-Au collisions at midrapidity at $\sqrt{s_{NN}}=3$ GeV. We derive analytic formulas of momentum distributions of two bodies, three bodies and four nucleons coalescing into light nuclei, respectively. We naturally explain the transverse momentum spectra of the deuteron ($d$), triton ($t$), helium-3 (${}^3$He) and helium-4 (${}^4$He). We reproduce the data of yield rapidity densities and averaged transverse momenta of $d$, $t$, ${}^3$He and ${}^4$He. We give proportions of contributions from different coalescence sources for $t$, ${}^3$He and ${}^4$He in their productions. We find that besides nucleon coalescence, nucleon$+$nucleus coalescence and nucleus$+$nucleus coalescence may play requisite roles in light nuclei production in Au-Au collisions at $\sqrt{s_{NN}}=3$ GeV.

   hep-phnucl-thCPC(2024)·6 citations
4. 04*

   Global analyses of nuclear PDFs with heavy-quark and neutrino data

   M. Klasen🇩🇪 · P. Duwentäster🇫🇮 · T. Jezo🇩🇪 · K. Kovarik🇩🇪 · A. Kusina🇵🇱 · J.G. Morfin🇺🇸 · K.F. Muzakka🇩🇪 · F.I. Olness🇺🇸 · R. Ruiz🇵🇱 · I. Schienbein🇫🇷 · J.Y. Yu🇫🇷

   We discuss the two most recent global analyses of nuclear parton distribution functions within the nCTEQ approach. LHC data on $W/Z$-boson, single-inclusive hadron and heavy quark/quarkonium production are shown to not only significantly reduce the gluon uncertainty down to $x\ge 10^{-5}$, but to also influence the strange quark density. The latter is further constrained by neutrino deep-inelastic scattering and charm dimuon production data, whose consistency with neutral-current experiments is also re-evaluated.

   hep-phhep-exnucl-exPoS(2022)·3 citations
5. 05*

   A review of neutrino decoupling from the early universe to the current universe

   Kensuke Akita🇰🇷 · Masahide Yamaguchi🇯🇵

   We review the distortions of spectra of relic neutrinos due to the interactions with electrons, positrons, and neutrinos in the early universe. We solve integro-differential kinetic equations for the neutrino density matrix, including vacuum three-flavor neutrino oscillations, oscillations in electron and positron background, a collision term and finite temperature corrections to electron mass and electromagnetic plasma up to the next-to-leading order $\mathcal{O}(e^3)$. After that, we estimate the effects of the spectral distortions in neutrino decoupling on the number density and energy density of the Cosmic Neutrino Background (C$\nu$B) in the current universe, and discuss the implications of these effects on the capture rates in direct detection of the C$\nu$B on tritium, with emphasis on the PTOLEMY-type experiment. In addition, we find a precise value of the effective number of neutrinos, $N_{\mathrm{eff}}=3.044$. However, QED corrections to weak interaction rates at order $\mathcal{O}(e^2{G}_F^2)$ and forward scattering of neutrinos via their self-interactions have not been precisely taken into account in the whole literature so far. Recent studies suggest that these neglections might induce uncertainties of $\pm (10^{-3}-10^{-4})$ in $N_{\mathrm{eff}}$.

   hep-phastro-ph.COUniverse(2022)·18 citations
6. 06*

   On the odderon mechanism for transverse single spin asymmetry in the Wandzura-Wilczek approximation

   Sanjin Benić🇭🇷 · Davor Horvatić🇭🇷 · Abhiram Kaushik🇭🇷 · Eric Andreas Vivoda🇭🇷

   We compute the transverse single spin asymmetry in forward $p^{\uparrow }p\to hX$ and $p^{\uparrow }A\to hX$ collisions from the odderon mechanism originally suggested by Kovchegov and Sievert [1]. Working in the hybrid approach of the Color Glass Condensate effective theory we firstly identify the relevant collinear parton distribution function (PDF) of the transversely polarized proton $p^{\uparrow }$ as the intrinsic twist-3 $g_T(x)$ distribution. We further argue that the complete polarized cross section also contains contributions from the kinematical and the dynamical twist-3 PDFs, in addition to the intrinsic twist-3 PDF. By restricting to the Wandzura-Wilczek approximation, where the dynamical twist-3 PDFs are dropped, we find that the odderon contribution to the polarized cross section for inclusive hadron production is exactly zero at the next-to-leading order in the strong coupling.

   hep-phPRD(2022)·7 citations
7. 07*

   Quantum transport theory with vector interaction

   Peiwei Yu🇨🇳 · Xingyu Guo🇨🇳

   We derive the relativistic quantum kinetic equation for massless fermions with vector and axial vector interaction using the Wigner function formalism. The vector and axial vector currents are self-consistently treated with corresponding constraint equations. The kinetic equations are derived and the condition for equilibrium is discussed up to the first order of $\hslash$. In addition to the vorticity and shear contributions, the divergence of the local particle number density is also found to contribute to the kinetic equations.

   hep-ph0 citations
8. 08*

   Investigation of production of neutral Higgs boson and two charged charginos from electron-positron annihilation via different propagators

   Sara Abdelrady Hassan🇪🇬 · Asmaa.A. A🇪🇬 · Sherif Yehia🇪🇬 · M. M. Ahmed🇪🇬 · Mohammed Said Mohammed Abu-Elmagd🇪🇬

   In the current work, We investigated the production of neutral Higgs boson and two charged Charginos owing to electron-positron annihilation via different propagators

   hep-ph0 citations
9. 09*

   Light quark decays of doubly heavy baryons in light front approach

   Hang Liu🇨🇳 · Zhi-Peng Xing🇨🇳 · Chang Yang🇨🇳

   We explore the semileptonic and nonleptonic decays of doubly heavy baryons $({\Omega }_{cc}^{(\ast )+},{\Omega }_{bb}^{(\ast )0},{\Omega }_{bc}^{(\ast )-},{\Omega }_{bc}^{\prime 0})$ induced by the $s\to u$ transition. Hadronic form factors are parametrized by transition matrix elements and are calculated in the light front quark model. With the form factors, we make use of helicity amplitudes and analyze semileptonic and nonleptonic decay modes of doubly heavy baryons. Benchmark results for partial decay widths, branching fractions, forward-backward asymmetries and other phenomenological observables are derived. We find that typical branching fractions for semileptonic decays into $\ell \bar{\nu }$ are at the order $10^{-7}-10^{-8}$ and the ones for nonleptonic decays are at the order $10^{-5}$, which are likely detectable such as in LHCb experiment. With the potential data accumulated in future, our results may help to shape our understanding of the decay mechanism in the presence of two heavy quarks.

   hep-phEPJC(2023)·12 citations
10. 10*

    Testing of KNO-scaling of charged hadron multiplicities within a Machine Learning based approach

    Gábor Bíró🇭🇺 · Bence Tankó-Bartalis🇭🇺 · Gergely Gábor Barnaföldi🇭🇺

    The results of a Machine Learning-based method is presented here to investigate the scaling properties of the final state charged hadron and mean jet multiplicity distributions. Deep residual neural network architectures with different complexities are utilized to predict the final state multiplicity distribution from the parton-level final state, generated by the \textsc{Pythia} Monte Carlo event generator. Hadronization networks were trained by $\sqrt{s}=7$ TeV events, while predictions have been made for various LHC energies from $\sqrt{s}=0.9$ TeV to 13 TeV. Scaling properties were adopted by the networks at hadronic level, indeed KNO-scaling is preserved -- although, the scaling of the mean jet multiplicity distributions varies for the applied models.

    hep-phphysics.comp-phPoS(2022)·1 citation
11. 11*

    On the decay widths of radially excited scalar meson $K_0^{\ast }(1430)$ in view of new experimental data

    M.K. Volkov🇷🇺 · K. Nurlan🇷🇺 · A.A. Pivovarov🇷🇺

    Decays of scalar mesons $K_0^{\ast }(800)\to K\pi$ and $K_0^{\ast }(1430)\to K\pi ,K\eta ,K{\eta }^{\prime },K_1\pi$ are described in the extended $U(3)\times U(3)$ Nambu - Jona-Lasinio chiral quark model. The obtained results are in satisfactory agreement with the new experimental data obtained by the BaBar collaboration, which markedly differ from the existing values in the PDG.

    hep-phEPJA(2023)·5 citations
12. 12*

    Dilepton production in the photodisintegration of the deuteron

    Mengchu Cai🇨🇳 · Tianbo Liu🇨🇳 · Bo-Qiang Ma🇨🇳

    We study the lepton pair production in the photodisintegration of the deuteron process. The complete seven-fold differential cross section is calculated via the Bethe-Heitler mechanism with final state interactions taken into account. The deuteron bound state is described by a relativistic covariant deuteron-nucleon vertex. With numerical results, we find that the differential cross section has strong dependence on the lepton azimuthal angle in the small polar angle region and sharp peaks appear in the dependence on the invariant mass of the produced lepton pair or the two nucleons in the final state. We demonstrate that such nearly singular feature originates from the collinearity between the produced lepton or antilepton and the incident photon, and it is physically regularized by the lepton mass in our calculation. The final state interaction between the knocked-out nucleon and the recoil nucleon redistributes the differential cross section over the missing momentum, with a significant enhancement at large missing momentum and a suppression in the intermediate region. With a further decomposition of the final state interaction contribution, it is found that the on-shell term dominates the near quasi-elastic region while the off-shell term dominates the other end. In addition, we examine the contribution from the interference between the proton amplitude and the neutron amplitude, which as expected is found negligible even if the proton-neutron rescattering is included. The result in this work can serve as an input for the analysis and background estimation of multiple exclusive measurements at Jefferson Lab and future electron-ion colliders.

    hep-phhep-exnucl-exnucl-thCPC(2024)·1 citation
13. 13*

    Recursion-free solution for two-loop vacuum integrals with "collinear" masses

    Andrei I. Davydychev🇨🇱 · York Schröder🇨🇱

    We investigate the structure of a particular class of massive vacuum Feynman integrals at two loops. This class enjoys the linear relation $m_1+m_2=m_3$ between its three propagator masses, corresponding to zeros of the associated Källén function. Apart from having applications in thermal field theory, the integrals can be mapped onto one-loop three-point functions with collinear external momenta, suggesting the term "collinear" masses. We present a closed-form solution for these integrals, proving that they can always be factorized into products of one-loop cases, for all integer-valued propagator powers.

    hep-phhep-thJHEP(2022)·9 citations
14. 14*

    High Energy Resummed Predictions for the Production of a Higgs Boson with at least One Jet

    Jeppe R. Andersen🇬🇧 · Hitham Hassan🇬🇧 · Andreas Maier🇩🇪 · Jérémy Paltrinieri🇬🇧 · Andreas Papaefstathiou🇺🇸 · Jennifer M. Smillie🇬🇧

    We present all-order predictions for Higgs boson production plus at least one jet which are accurate to leading logarithm in $\hat{s}/|p_{\perp }{|}^2$. Our calculation includes full top and bottom quark mass dependence at all orders in the logarithmic part, and to highest available order in the tree-level matching. The calculation is implemented in the framework of High Energy Jets (HEJ). This is the first cross section calculated with $\log (\hat{s})$ resummation and matched to fixed order for a process requiring just one jet, and our results also extend the region of resummation for processes with two jets or more. This is possible because the resummation is performed explicitly in phase space. We compare the results of our new calculation to LHC data and to next-to-leading order predictions and find a numerically significant impact of the logarithmic corrections in the shape of key distributions, which remains after normalisation of the cross section.

    hep-phJHEP(2023)·24 citations
15. 15*

    Transverse momentum resummation at N3LL+NNLO for diboson processes

    John M. Campbell🇺🇸 · R. Keith Ellis🇬🇧 · Tobias Neumann🇺🇸 · Satyajit Seth🇮🇳

    Diboson processes are one of the most accessible and stringent probes of the Standard Model's electroweak gauge structure at the LHC. They will be probed at the percent level at the high-luminosity LHC, challenging current theory predictions. We present transverse momentum resummed calculations at N3LL+NNLO for the processes $ZZ$, $WZ$, $WH$ and $ZH$, compare our predictions with most recent LHC data and present predictions at 13.6 TeV including theory uncertainty estimates. For $W^{+}{W}^{-}$ production we further present jet-veto resummed results at N3LLp+NNLO. Our calculations will be made publicly available in the upcoming MCFM release and allow future analyses to take advantage of improved predictions.

    hep-phJHEP(2023)·14 citations
16. 16*

    Inflation and Electroweak Symmetry Breaking

    Stephon Alexander🇺🇸

    We present a model of Cosmological Electroweak Symmetry Breaking (CEWSB), where a Higgs-like field and a cosmological background of weak boson gauge fields interact with gravity to realize the epoch of cosmic inflation, which is then followed by a Higgs resonance preheating. As a result, the scale of electroweak symmetry breaking is linked with the end of inflation. The theory is equipped with a shift symmetry that can protect the Higgs mass, and it has close semblance to natural inflation and its variants. As the Higgs field's amplitude decays at the end of inflation, its mass emerges. The model has a built in Higgs self-resonance preheating mechanism which leads to the possible emergence of the cosmic microwave background (CMB) due to resonant Higgs, quark and lepton production after inflation. We provide a pathway to implement a similar mechanism with the realistic Higgs-doublet of the standard electroweak theory and discuss phenomenological considerations.

    hep-phastro-ph.COgr-qchep-thJCAP(2023)·2 citations
17. 17*

    Simulating lepton number violation induced by heavy neutrino-antineutrino oscillations at colliders

    Stefan Antusch🇨🇭 · Jan Hajer🇵🇹 · Johannes Rosskopp🇨🇭

    We study pseudo-Dirac pairs of two almost mass-degenerate sterile Majorana neutrinos which generate light neutrino masses via a low-scale seesaw mechanism. These pseudo-Dirac heavy neutral leptons can oscillate between interaction eigenstates that couple to leptons and antileptons and thus generate oscillations between lepton number conserving and lepton number violating processes. With the phenomenological symmetry protected seesaw scenario (pSPSS), we introduce a minimal framework capable of describing the dominant features of low-scale seesaws at colliders and present a FeynRules implementation usable in Monte Carlo generators. Additionally, we extend MadGraph to simulate heavy neutrino-antineutrino oscillations and present results from such simulations.

    hep-phhep-exJHEP(2023)·28 citations
18. 18*

    Global fit to $b\to c\tau \nu$ anomalies 2022 mid-autumn

    Syuhei Iguro🇩🇪 · Teppei Kitahara🇯🇵 · Ryoutaro Watanabe🇮🇹

    Recently, the LHCb collaboration announced a preliminary result of the test of lepton flavor universality (LFU) in $B\to D^{(\ast )}$ semi-leptonic decays: $R_D^{LHCb2022}=0.441\pm 0.089$ and $R_{D^{\ast }}^{LHCb2022}=0.281\pm 0.030$ based on the LHC Run 1 data. This is the first result of $R_D$ for the LHCb experiment, and its precision is comparable to the other $B$-factory data. Interestingly, those data prefer the violation of the LFU again. A new world average of the data from the BaBar, Belle, and LHCb collaborations is $R_D=0.358\pm 0.027$ and $R_{D^{\ast }}=0.285\pm 0.013$. Including this new data, we update a circumstance of the $b\to c\tau \overline{\nu }$ measurements and their implications for new physics. Incorporating recent developments for the $B\to D^{(\ast )}$ form factors in the Standard Model (SM), we observe a $4.1\sigma$ deviation from the SM predictions. Our updates also include; model-independent new physics (NP) formulae for the related observables; and the global fittings of parameters for leptoquark scenarios as well as single NP operator scenarios. Furthermore, we show future potential to indirectly distinguish different new physics scenarios with the use of the precise measurements of the polarization observables in $B\to D^{(\ast )}\tau \overline{\nu }$ at the Belle II and the high-$p_{\mathrm{T}}$ flavored-tail searches at the LHC. We also discuss an impact on the LFU violation in ${\rm Y}\to l^{+}{l}^{-}$.

    hep-phhep-ex62 citations
19. 19*

    Entering the Era of Measuring Sub-Galactic Dark Matter Structure: Accurate Transfer Functions for Axino, Gravitino & Sterile Neutrino Thermal Warm Dark Matter

    Cannon M. Vogel🇺🇸 · Kevork N. Abazajian🇺🇸

    We examine thermal warm dark matter (WDM) models that are being probed by current constraints, and the relationship between the particle dark matter spin and commensurate thermal history. We find significant corrections to the linear matter power spectrum for given thermal WDM particle masses. Two primary classes are examined: spin-1/2 particles (e.g., thermalized sterile neutrinos, axinos) and thermal spin-3/2 particles (e.g., gravitinos or non-supersymmetric particles). We present new transfer function fits for thermal WDM candidates in particle mass regimes beyond the range of previous work, and at the scales of current and upcoming constraints. Importantly, we find that the standard, predominantly used, spin-1/2, thermal WDM particle produces a colder transfer function than that determined in previous work. We also analyze the entropy requirements for these WDM models to successfully produce observed dark matter densities. We explore the early Universe physics of gravitinos as either partially thermalized or fully thermalized species, which considerably changes the particle dark matter candidates' thermalization history and effects on structure formation. For the first time, we also calculate the transfer function for thermal spin-3/2 WDM.

    hep-phastro-ph.COPRD(2023)·27 citations
20. 20*

    Completing RHINO

    Pasquale Di Bari🇬🇧 · Adam Murphy🇬🇧

    The right-handed (RH) Higgs-induced neutrino mixing (RHINO) model explains neutrino masses and origin of matter in the universe within a unified picture. The mixing, effectively described by a dimension five operator, is responsible both for the production of dark neutrinos, converting a small fraction of seesaw neutrinos acting as source, and for their decays. We show that including the production of source neutrinos from Higgs portal interactions, their abundance can thermalise prior to the onset of source-dark neutrino oscillations, resulting into an enhanced production of dark neutrinos that thus can play the role of decaying dark matter (DM) for a much higher seesaw scale. This can be above the sphaleron freeze-out temperature and as high as $\sim 100\mathrm{TeV}$, so that strong thermal resonant leptogenesis for the generation of the matter-antimatter asymmetry is viable. We obtain a $\sim 1\mathrm{TeV}$--$1\mathrm{PeV}$ allowed dark neutrino mass range. Intriguingly, their decays can also explain a neutrino flux excess at $\mathcal{O}(100\mathrm{TeV})$ energies recently confirmed by the IceCube collaboration analysing 7.5yr HESE data. Our results also point to an effective scale for Higgs portal interactions nicely identifiable with the grandunified scale and many orders of magnitude below the effective scale for the mixing. We explain this hierarchy in a UV-complete model with a very heavy fermion as mediator: the first scale corresponds to the fundamental scale of new physics, while the second is much higher because of a very small coupling identifiable with a symmetry breaking parameter. Therefore, RHINO realises a simple unified model of neutrino masses and origin of matter in the universe currently under scrutiny at neutrino telescopes and potentially embeddable within a grandunified model.

    hep-phastro-ph.COastro-ph.HEJHEP(2023)·1 citation
21. 21*

    Energy of boundary of spacetime

    Yu Hamada🇯🇵 · Nobuyuki Matsumoto🇺🇸

    We consider how the energy can be stored in the boundary of spacetime, in particular in a spherical bubble that can be made by a quantum gravitational process. Our calculation is performed within the framework of classical Einstein gravity by identifying the Gibbons-Hawking-York term as the membrane action. We show that the energy of the bubble can be given consistently with the Schwarzschild metric. The solution of the consistency condition suggests positive membrane tension, which explains why we do not observe such topological defects in ordinary experiences and also gives a mechanism for suppressing the spacetime with boundary in a dynamical way.

    ↳ hep-thgr-qchep-phPTEP(2023)·0 citations
22. 22*

    First Simultaneous K${}^{-}$p $\to ({\Sigma }^0/\Lambda ){\pi }^0$ Cross Sections Measurements at 98 MeV/c

    Kristian Piscicchia🇮🇹 · Magdalena Skurzok🇵🇱 · Michael Cargnelli🇦🇹 · Raffaele Del Grande🇮🇹 · Laura Fabbietti🇩🇪 · Johann Marton🇦🇹 · Pawel Moskal🇵🇱 · Alessandro Scordo🇮🇹 · Àngels Ramos🇪🇸 · Diana Laura Sirghi🇮🇹 · Oton Vazquez Doce🇮🇹 · Johann Zmeskal🇦🇹 and 15 other authors

    We report the first simultaneous and independent measurements of the K${}^{-}$p $\to {\Sigma }^0{\pi }^0$ and K${}^{-}$p $\to \Lambda {\pi }^0$ cross sections around 100 MeV/c kaon momentum. The kaon beam delivered by the DA$\Phi$NE collider was exploited to detect K${}^{-}$ absorptions on Hydrogen atoms, populating the gas mixture of the KLOE drift chamber. The precision of the measurements (${\sigma }_{K^{-}p\to {\Sigma }^0{\pi }^0}=42.8\pm 1.5(stat.{)}_{-2.0}^{+2.4}(syst.)\mathrm{mb}$ and ${\sigma }_{K^{-}p\to \Lambda {\pi }^0}=31.0\pm 0.5(stat.{)}_{-1.2}^{+1.2}(syst.)\mathrm{mb}$) is the highest yet obtained in the low kaon momentum regime.

    ↳ nucl-exhep-phPRC(2023)·11 citations
23. 23*

    Probing the singularities of the Landau-gauge gluon and ghost propagators with rational approximants

    Diogo Boito🇧🇷 · Attilio Cucchieri🇧🇷 · Cristiane Y. London🇧🇷 · Tereza Mendes🇧🇷

    We employ Padé approximants in the study of the analytic structure of the four-dimensional $SU(2)$ Landau-gauge gluon and ghost propagators in the infrared regime. The approximants, which are model independent, serve as fitting functions for the lattice data. We carefully propagate the uncertainties due to the fitting procedure, taking into account all possible correlations. For the gluon-propagator data, we confirm the presence of a pair of complex poles at $p_{\mathrm{pole}}^2=\left[(-0.37\pm 0.05_{\mathrm{stat}}\pm 0.08_{\mathrm{sys}})\pm i(0.66\pm 0.03_{\mathrm{stat}}\pm 0.02_{\mathrm{sys}})\right]{\mathrm{GeV}}^2$, where the first error is statistical and the second systematic. The existence of this pair of complex poles, already hinted upon in previous works, is thus put onto a firmer basis, thanks to the model independence and to the careful error propagation of our analysis. For the ghost propagator, the Padés indicate the existence of a single pole at $p^2=0$, as expected. In this case, our results also show evidence of a branch cut along the negative real axis of $p^2$. This is corroborated with another type of approximant, the D-Log Padés, which are better suited to studying functions with a branch cut and are applied here for the first time in this context. Due to particular features and limited statistics of the gluon-propagator data, our analysis is inconclusive regarding the presence of a branch cut in the gluon case.

    ↳ hep-lathep-phJHEP(2023)·18 citations
24. 24*

    Gauge Invariance at Large Charge

    Oleg Antipin🇭🇷 · Alexander Bednyakov🇷🇺 · Jahmall Bersini🇭🇷 · Pantelis Panopoulos🇭🇷 · Andrey Pikelner🇷🇺

    Quantum field theories with global symmetries simplify considerably in the large-charge limit allowing to compute correlators via a semiclassical expansion in the inverse powers of the conserved charges. A generalization of the approach to gauge symmetries has faced the problem of defining gauge-independent observables and, therefore, has not been developed so far. We employ the large-charge expansion to calculate the scaling dimension of the lowest-lying operators carrying $U(1)$ charge $Q$ in the critical Abelian Higgs model in $D=4-ϵ$ dimensions to leading and next-to-leading orders in the charge and all orders in the $ϵ$ expansion. Remarkably, the results match our independent diagrammatic computation of the three-loop scaling dimension of the operator ${\varphi }^Q(x)$ in the Landau gauge. We argue that this matching is a consequence of the equivalence between the gauge-independent dressed two-point function of Dirac type with the gauge-dependent two-point function of ${\varphi }^Q(x)$ in the Landau gauge. We, therefore, shed new light on the problem of defining gauge-independent exponents which has been controversial in the literature on critical superconductors as well as lay the foundation for large-charge methods in gauge theories.

    ↳ hep-thcond-mat.stat-mechhep-phPRL(2023)·9 citations
25. 25*

    Distinguishing a Slowly Accelerating Black Hole by Differential Time Delays of Images

    Amjad Ashoorioon🇮🇷 · Mohammad Bagher Jahani Poshteh🇮🇷 · Robert B. Mann🇨🇦

    Accelerating supermassive black holes, connected to cosmic strings, could contribute to structure formation and get captured by galaxies if their velocities are small. This would mean that the acceleration of these black holes is small too. Such a slow acceleration has no significant effect on the shadow of such supermassive black holes. We also show that, for slowly accelerating black holes, the angular position of images in the gravitational lensing effects do not change significantly. We propose a method to observe the acceleration of these black holes through the gravitational lensing. The method is based on the observation that differential time delays associated with the images are substantially different with respect to the case of non-accelerating black holes.

    ↳ gr-qcastro-ph.COhep-phhep-thPRL(2022)·21 citations
26. 26*

    A quantum analytical Adam descent through parameter shift rule using Qibo

    Matteo Robbiati🇮🇹 · Stavros Efthymiou🇦🇪 · Andrea Pasquale🇮🇹 · Stefano Carrazza🇮🇹

    In this proceedings we present quantum machine learning optimization experiments using stochastic gradient descent with the parameter shift rule algorithm. We first describe the gradient evaluation algorithm and its optimization procedure implemented using the Qibo framework. After numerically testing the implementation using quantum simulation on classical hardware, we perform successfully a full quantum hardware optimization exercise using a single superconducting qubit chip controlled by Qibo. We show results for a quantum regression model by comparing simulation to real hardware optimization.

    ↳ quant-phhep-phPoS(2022)·11 citations
27. 27*

    Multifield Positivity Bounds for Inflation

    Marat Freytsis🇺🇸 · Soubhik Kumar🇺🇸 · Grant N. Remmen🇺🇸 · Nicholas L. Rodd🇨🇭

    Positivity bounds represent nontrivial limitations on effective field theories (EFTs) if those EFTs are to be completed into a Lorentz-invariant, causal, local, and unitary framework. While such positivity bounds have been applied in a wide array of physical contexts to obtain useful constraints, their application to inflationary EFTs is subtle since Lorentz invariance is spontaneously broken during cosmic inflation. One path forward is to employ a $\text{Breit parameterization}$ to ensure a crossing-symmetric and analytic S-matrix in theories with broken boosts. We extend this approach to a theory with multiple fields, and uncover a fundamental obstruction that arises unless all fields obey a dispersion relation that is approximately lightlike. We then apply the formalism to various classes of inflationary EFTs, with and without isocurvature perturbations, and employ this parameterization to derive new positivity bounds on such EFTs. For multifield inflation, we also consider bounds originating from the generalized optical theorem and demonstrate how these can give rise to stronger constraints on EFTs compared to constraints from traditional elastic positivity bounds alone. We compute various shapes of non-Gaussianity (NG), involving both adiabatic and isocurvature perturbations, and show how the observational parameter space controlling the strength of NG can be constrained by our bounds.

    ↳ hep-thastro-ph.COhep-phJHEP(2023)·26 citations
28. 28*

    Spin-half bosons with mass dimension three half: Evading the spin-statistics theorem

    Dharam Vir Ahluwalia🇦🇺 · Cheng-Yang Lee🇨🇳

    By exploiting the freedom in defining the dual of spinors, we report an unexpected theoretical discovery of a quantum field theory of spin-half bosons. It fulfils Dirac's 1969-70 observation that "there must be boson variables connected with electrons." The theory is local, Lorentz-invariant, and has a positive-definite Hamiltonian. We formulate the unitarity-preserving scattering theory to accommodate the new dual and the associated adjoint. A model of Yukawa interaction with spin-half bosons and fermions of equal masses is studied to explicitly show unitarity.

    ↳ hep-thgr-qchep-phEPL(2022)·18 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.