Thu·Jun 2, 2022Thursday·June 2, 2022

1. 01*

   Neutrino Physics in TeV Scale Gravity Theories

   Manuel Ettengruber🇩🇪

   In this paper, the general features of the neutrino sector in TeV scale quantum gravity theories, such as ADD and Many Species Theory, is investigated. This class of theories has an inherent way to generate small neutrino masses. After reviewing this mechanism it is generalized to a realistic three-flavour case. Furthermore, a procedure is presented how to diagonalize a mass matrix which is generated by this class of theories and how one can find the Standard Model flavour eigenstates. The developed general approach is applied to two specific scenarios within ADD and Many Species Theory and possible effects on neutrino oscillations and on unitarity of the lepton mixing matrix are calculated. Finally, a short overview of phenomenology which can be potentially testable by the nowadays neutrino experiments is presented.

   hep-phPRD(2022)·15 citations
2. 02*

   Gravitational scattering of spinning neutrinos by a rotating black hole with a slim magnetized accretion disk

   Maxim Dvornikov (IZMIRAN)🇷🇺

   We study neutrinos gravitationally scattered off a rotating supermassive black hole which is surrounded by a thin accretion disk with a realistic magnetic field. Neutrinos are supposed to be Dirac particles having a nonzero magnetic moment. Neutrinos move along arbitrary trajectories, with the incoming flux being parallel to the equatorial plane. We exactly account for the influence of both gravity and the magnetic field on the neutrino motion and its spin evolution. The general statement that the helicity of an ultrarelativistic neutrino is constant in the particle scattering in an arbitrary gravitational field is proven within the quasiclassical approach. We find the measurable fluxes of outgoing neutrinos taking into account the neutrino spin precession in the external field in curved spacetime. These fluxes turn out to be significantly suppressed for some parameters of the system. Finally, we discuss the possibility to observe the predicted phenomena for core-collapsing supernova neutrinos in our Galaxy.

   hep-phastro-ph.HEgr-qcClass.Quant.Grav.(2023)·9 citations
3. 03*

   New extraction of CP violation in b-baryon decays

   Chao-Qiang Geng🇨🇳 · Xiang-Nan Jin🇨🇳 · Chia-Wei Liu🇨🇳 · Zheng-Yi Wei🇨🇳 · Jiabao Zhang🇨🇳

   We study CP violation in b-baryon decays of ${\Xi }_b^{-}\to {\Xi }^{-}D$ with $D=D^0,{\bar{D}}^0$ and $D_i(i=1,2)$. We find that these baryonic decay processes provide an ideal opportunity to measure the weak phase due to the absence of the relative strong phase. Explicitly, we relate $\bar{\rho }$ and $\bar{\eta }$ the CKM elements with the decay rate ratios of $R_i=\Gamma ({\Xi }_b^{-}\to {\Xi }^{-}{D}_i)/\Gamma ({\Xi }_b^{-}\to {\Xi }^{-}{D}^0)$ without the charge conjugate states. As a complementary, we also examine the decay distributions of ${\Lambda }_b\to \Lambda (\to p{\pi }^{-})D$. There are in total 32 decay observables, which can be parameterized by 9 real parameters, allowing the experiments to extract the angle $\gamma \equiv \arg (-V_{ud}{V}_{ub}^{\ast }/V_{cd}{V}_{cb}^{\ast })$ in the CKM unitarity triangle. In addition, the feasibilities of the experimental measurements are discussed. We find that $\bar{\rho }$ and $\bar{\eta }$ can be extracted at LHCb Run3 from ${\Xi }_b^{-}\to {\Xi }^{-}D$, and a full analysis of ${\Lambda }_b\to \Lambda (\to p{\pi }^{-})D$ is available at LHCb Run4.

   hep-phPLB(2022)·9 citations
4. 04*

   Defining the Underlying-Event Activity in the Presence of Heavy-Flavour Processes in Proton-Proton Collisions at LHC Energies

   László Gyulai🇭🇺 · Szende Sándor🇭🇺 · Róbert Vértesi🇭🇺

   We present a systematic analysis of heavy-flavour production in the underlying event in connection to a leading hard process in pp collisions at $\sqrt{s}$ = 13 TeV, using the PYTHIA 8 Monte Carlo event generator. We compare results from events selected by triggering on the leading hadron, as well as those triggered with reconstructed jets. We show that the kinematics of heavy-flavour fragmentation complicates the characterisation of the underlying event, and the usual method which uses the leading charged final-state hadron as a trigger may wash away the connection between the leading process and the heavy-flavour particle created in association with that. Events triggered with light or heavy-flavour jets, however, retain this connection and bring more direct information on the underlying heavy-flavour production process, but may also import unwanted sensitivity to gluon radiation. The methods outlined in the current work provide means to verify model calculations for light and heavy-flavour production in the jet and the underlying event in great details.

   hep-phnucl-thParticles(2022)·1 citation
5. 05*

   Critical point influenced by Bose-Einstein condensation

   V. A. Kuznietsov🇺🇦 · O. Savchuk🇺🇦 · O. S. Stashko🇺🇦 · M. I. Gorenstein🇺🇦

   A system of bosons studied within the mean field framework has two fascinating phenomena: a liquid-gas first order phase transition and Bose-Einstein condensation. Interplay between these two phenomena is being investigated. Depending on the mean-field potential parameters one can observe two types of critical points, called "Boltzmann" and "Bose", that belong to different universality classes with distinct sets of critical exponents. As examples of Bose and Boltzmann CPs pion and $\alpha$ matter are considered, respectively. In general, the phase diagram can have one of the CPs or both of them.

   hep-phPRC(2022)·2 citations
6. 06*

   QCD preheating: New frontier of baryogenesis

   Xin-Ru Wang🇨🇳 · Jin-Yang Li🇨🇳 · Seishi Enomoto🇨🇳 · Hiroyuki Ishida🇯🇵 · Shinya Matsuzaki🇨🇳

   We find that QCD can create the cosmological matter abundance via out-of-equilibrium processes during the QCD phase transition, that is what we call the QCD preheating, where the dynamic transition of the QCD vacuum characterized by the quark condensate takes place instantaneously. This mechanism works when the Universe undergoes subsequent supercooled QCD transition. We also find that the QCD preheating can work to create the baryon asymmetry of the Universe if there is the new physics communicated with QCD. These are new pictures of the thermal history around the QCD-phase transition epoch, and thus the dynamic aspect of the QCD vacuum opens a new frontier to explore low-scale matter generation such as baryogenesis. Pursuing the QCD reheating era would also help deeply understanding the subatomic-scale physics in the thermal history of the Universe.

   hep-phPRD(2023)·6 citations
7. 07*

   Charged lepton flavor violating processes in the Grimus-Neufeld model

   Vytautas Dūdėnas🇱🇹 · Thomas Gajdosik🇱🇹 · Uladzimir Khasianevich🇩🇪 · Wojciech Kotlarski🇵🇱 · Dominik Stöckinger🇩🇪

   Charged Lepton Flavour Violating (cLFV) decays constrain the relationship between the neutrino and the scalar sectors of the Grimus-Neufeld model (GNM), an appealing minimal model of neutrino masses. It turns out, that in the scenario, where the seesaw scale is lower than the electroweak one, cLFV is completely defined by the new Yukawa interactions between the additional single heavy Majorana neutrino, the second Higgs doublet and the lepton doublets. Therefore, we derive a useful parameterization for the Yukawa couplings which reproduces by construction the correct PMNS matrix and the correct neutrino masses for both Normal and Inverted ordering at one-loop level. We embed this scenario in the $\text{FlexibleSUSY}$ spectrum-generator generator to perform parameter scans. Focusing on the tiny seesaw scale, we show that current $\mu \to e\gamma$ limits provide significant constraints on the scalar sector, and we evaluate the impact of future cLFV $\tau$-decay searches for the cases of discovery or non-discovery. The tiny seesaw scale makes the neutrino sector and the cLFV processes in the GNM similar to the scotogenic and the scoto-seesaw models, so we provide constraints for these models as well.

   hep-phJHEP(2022)·10 citations
8. 08*

   Axiogenesis with a Heavy QCD Axion

   Raymond T. Co🇺🇸 · Tony Gherghetta🇺🇸 · Keisuke Harigaya🇨🇭

   We demonstrate that the observed cosmological excess of matter over antimatter may originate from a heavy QCD axion that solves the strong CP problem but has a mass much larger than that given by the Standard Model QCD strong dynamics. We investigate a rotation of the heavy QCD axion in field space, which is transferred into a baryon asymmetry through weak and strong sphaleron processes. This provides a strong cosmological motivation for heavy QCD axions, which are of high experimental interest. The viable parameter space has an axion mass $m_a$ between 1~MeV and 10 GeV and a decay constant $f_a<10^5$ GeV, which can be probed by accelerator-based direct axion searches and observations of the cosmic microwave background.

   hep-phJHEP(2022)·34 citations
9. 09*

   Scattering of a twisted electron wavepacket by a finite laser pulse

   I. A. Aleksandrov🇷🇺 · D. A. Tumakov🇷🇺 · A. Kudlis🇷🇺 · V. A. Zaytsev🇷🇺 · N. N. Rosanov🇷🇺

   The behavior of a twisted electron colliding with a linearly polarized laser pulse is investigated within relativistic quantum mechanics. In order to better fit the real experimental conditions, we introduce a Gaussian spatial profile for the initial electron state as well as an envelope function for the laser pulse, so the both interacting objects have a finite size along the laser propagation direction. For this setup we analyze the dynamics of various observable quantities regarding the electron state: the probability density, angular momentum, and mean values of the spatial coordinates. It is shown that the motion of a twisted wavepacket can be accurately described by averaging over classical trajectories with various directions of the transverse momentum component. On the other hand, full quantum simulations demonstrate that the ring structure of the wavepacket in the transverse plane can be significantly distorted leading to large uncertainties in the total angular momentum of the electron. This effect remains after the interaction once the laser pulse has a nonzero electric-field area.

   ↳ quant-phhep-phPRA(2022)·6 citations
10. 10*

    Noether's 1st theorem with local symmetries

    Sinya Aoki🇯🇵

    Noether's 2nd theorem applied to a total system states that a global symmetry which is a part of local symmetries does not provide a physically meaningful conserved charge but it instead leads to off-shell constraints as a form of conserved currents. In this paper, we propose a general method to derive a matter conserved current associated with a special global symmetry in the presence of local symmetries. While currents derived from local symmetries of a matter sector with a covariant background gauge field are not conserved in general, we show that the current associated with a special type of a global symmetry, called a hidden matter symmetry, is on-shell conserved. We apply this derivation to a $U(1)$ gauge theory, general relativity and a non-abelian gauge theory. In general relativity, the associated conserved charge agrees with the one recently proposed from a different point of view.

    ↳ hep-thgr-qchep-lathep-phPTEP(2022)·10 citations
11. 11*

    Dynamical Abelianization and anomalies in chiral gauge theories

    Stefano Bolognesi🇮🇹 · Kenichi Konishi🇮🇹 · Andrea Luzio🇮🇹

    We explore the idea that in some class of strongly-coupled chiral $SU(N)$ gauge theories the infrared dynamics might be characterized by a bifermion condensate in the adjoint representation of the color gauge group. As an illustration, in this work we revisit an $SU(N)$ chiral gauge theory with Weyl fermions in a symmetric ($\psi$) and anti-antisymmetric ($\chi$) tensor representations, together with eight fermions in the anti-fundamental representations ($\eta$), which we called $\psi \chi \eta$ model in the previous investigations. We study the infrared dynamics of this system more carefully, by assuming dynamical Abelianization, a phenomenon familiar from $\mathcal{N}=2$ supersymmetric gauge theories, and by analyzing the way various continuous and discrete symmetries are realized at low energies. We submit then these ideas to a more stringent test, by taking into account some higher-form symmetries and the consequent mixed anomalies. A detailed analysis of the mixed anomalies involving certain $0$-form $U(1)$ symmetries and the color-flavor locked $1$-form $Z_N$ symmetry in the $\psi \chi \eta$ system shows that the proposed infrared dynamics is consistent with it.

    ↳ hep-thhep-lathep-phJHEP(2022)·16 citations
12. 12*

    Fractal properties of particle paths due to generalised uncertainty relations

    Matthew J. Lake🇹🇭

    We determine the Hausdorff dimension of a particle path, $D_{\mathrm{H}}$, in the recently proposed `smeared space' model of quantum geometry. The model introduces additional degrees of freedom to describe the quantum state of the background and gives rise to both the generalised uncertainty principle (GUP) and extended uncertainty principle (EUP) without introducing modified commutation relations. We compare our results to previous studies of the Hausdorff dimension in GUP models based on modified commutators and show that the minimum length enters the relevant formulae in a different way. We then determine the Hausdorff dimension of the particle path in smeared momentum space, ${\tilde{D}}_{\mathrm{H}}$, and show that the minimum momentum is dual to the minimum length. For sufficiently coarse grained paths, $D_{\mathrm{H}}={\tilde{D}}_{\mathrm{H}}=2$, as in canonical quantum mechanics. However, as the resolutions approach the minimum scales, the dimensions of the paths in each representation differ, in contrast to their counterparts in the canonical theory. The GUP-induced corrections increase $D_{\mathrm{H}}$ whereas the EUP-induced corrections decrease ${\tilde{D}}_{\mathrm{H}}$, relative to their canonical values, and the extremal case corresponds to $D_{\mathrm{H}}=3$, ${\tilde{D}}_{\mathrm{H}}=1$. These results show that the GUP and the EUP affect the fractal properties of the particle path in fundamentally different, yet complimentary, ways.

    ↳ gr-qchep-phquant-phEPJC(2022)·3 citations
13. 13*

    Neutrino Decoupling Is Altered by Flavor Conversion

    Shashank Shalgar🇩🇰 · Irene Tamborra🇩🇰

    The large neutrino density in the deep interior of core-collapse supernovae and compact binary merger remnants makes neutrino flavor evolution non-linear because of the coherent forward scattering of neutrinos among themselves. Under the assumption of spherical symmetry, we model neutrino decoupling from matter in an idealized setup and present the first non-linear simulation of flavor evolution in the presence of charged current and neutral current collisions, as well as neutrino advection. Within our framework, we find that flavor transformation occurs before neutrinos fully decouple from matter, dynamically affecting the flavor distributions of all neutrino species and shifting the location of the neutrino decoupling surfaces. Our results call for further work as they may have implications on the explosion mechanism of supernovae, the nucleosynthesis of the heavy elements, as well as the observable neutrino signal, all of which is yet to be assessed.

    ↳ astro-ph.HEhep-phPRD(2023)·59 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.