Fri·Jun 5, 2020Friday·June 5, 2020

1. 01*

   Migdal effect and photon Bremsstrahlung: improving the sensitivity to light dark matter of liquid argon experiments

   Giovanni Grilli di Cortona🇵🇱 · Andrea Messina🇮🇹 · Stefano Piacentini🇮🇹

   The search for dark matter weakly interacting massive particles with noble liquids has probed masses down and below a GeV/c^2. The ultimate limit is represented by the experimental threshold on the energy transfer to the nuclear recoil. Currently, the experimental sensitivity has reached a threshold equivalent to a few ionization electrons. In these conditions, the contribution of a Bremsstrahlung photon or a so-called Migdal electron due to the sudden acceleration of a nucleus after a collision might be sizable. In the present work, we use a Bayesian approach to study how these effects can be exploited in experiments based on liquid argon detectors. In particular, taking inspiration from the DarkSide-50 public spectra, we develop a simulated experiment to show how the Migdal electron and the Bremsstrahlung photon allow to push the experimental sensitivity down to masses of 0.1 GeV/c^2, extending the search region for dark matter particles of previous results. For these masses we estimate the effect of the Earth shielding that, for strongly interacting dark matter, makes any detector blind. Finally, we show how the sensitivity scales for higher exposure.

   hep-phastro-ph.COhep-exJHEP(2020)·59 citations
2. 02*

   Two-loop HTL-resummed thermodynamics for N=4 supersymmetric Yang-Mills theory

   Qianqian Du🇨🇳 · Michael Strickland🇺🇸 · Ubaid Tantary🇺🇸 · Ben-Wei Zhang🇨🇳

   We compute the two-loop hard-thermal-loop (HTL) resummed thermodynamic potential for N=4 supersymmetric Yang-Mills (SYM). Our final result is manifestly gauge-invariant and was renormalized using only simple vacuum energy, gluon mass, scalar mass, and quark mass counter terms. The HTL mass parameters m_D, M_D, and m_q are then determined self-consistently using a variational prescription which results in a set of coupled gap equations. Based on this, we obtain the two-loop HTL-resummed thermodynamic functions of N=4 SYM. We compare our final result with known results obtained in the weak- and strong-coupling limits. We also compare to previously obtained approximately self-consistent HTL resummations and Padé approximants. We find that the two-loop HTL resummed results for the scaled entropy density is a quantitatively reliable approximation to the scaled entropy density for 0 <= lambda <~ 2 and is in agreement with previous approximately self-consistent HTL resummation results for lambda <~ 6.

   hep-phhep-thnucl-thJHEP(2020)·11 citations
3. 03*

   New perspective in searching for axion-like particles from flavor physics

   Hiroyuki Ishida🇯🇵 · Shinya Matsuzaki🇨🇳 · Yoshihiro Shigekami🇨🇳

   We propose new perspective in searching for axion-like particles (ALPs) from quark and lepton flavor physics: measurements of the time-dependent CP asymmetry in $B^0\to K_S^0{\pi }^0\gamma$ and the branching ratio of $B_s\to e^{\pm }{\mu }^{\mp }$ decay possess, along with the anomalous magnetic moment of muon. In the mass range of sub-GeV, accessible by the flavorful ALPs search, the experimental sensitivity for these flavor observables reaches the maximum at around the pion mass scale (called the {\it sweetest} spots), where a couple of loopholes (unexplored regions) for the ALP parameter space have heretofore been present, because of an unavoidable contamination with pion background events. The proposed complementary probes can precisely determine the ALP coupling to photon at these {\it sweetest} spots/loopholes, and will significantly help cover whole parameter spaces in the ALP search including the present loopholes in the future.

   hep-phastro-ph.COhep-exPRD(2021)·11 citations
4. 04*

   Parton distribution function for the gluon condensate

   Yoshitaka Hatta🇺🇸 · Yong Zhao🇺🇸

   Motivated by the desire to understand the nucleon mass structure in terms of light-cone distributions, we introduce the twist-four parton distribution function $F(x)$ whose first moment is the gluon condensate in the nucleon. We present the equation of motion relations for $F(x)$ and discuss the possible existence of the delta function (`zero mode') contribution at $x=0$. We also perform one-loop calculations for quark and gluon targets.

   hep-phPRD(2020)·22 citations
5. 05*

   Weyl Scaling Invariant $R^2$ Gravity for Inflation and Dark Matter

   Yong Tang🇨🇳 · Yue-Liang Wu🇨🇳

   Inflation in the early universe can generate the nearly conformal invariant fluctuation that leads to the structures we observe at the present. The simple viable Starobinsky $R^2$ inflation has an approximate global scale symmetry. We study the conformal symmetric Weyl ${\hat{R}}^2$ and general $F(\hat{R})$ theories and demonstrate their equivalence to Einstein gravity coupled with a scalar and a Weyl gauge field. The scalar field in Weyl ${\hat{R}}^2$ gravity can be responsible for inflation with Starobinsky model as the attractor, potentially distinguishable from the latter by future experiments. The intrinsic Weyl gauge boson becomes massive once the Einstein frame is fixed, and constitutes as a dark matter candidate with mass up to $\sim 5\times 10^{16}$GeV.

   hep-phastro-ph.COgr-qcPLB(2020)·26 citations
6. 06*

   Relativistic corrections to the vector meson light front wave function

   Tuomas Lappi🇫🇮 · Heikki Mäntysaari🇫🇮 · Jani Penttala🇫🇮

   We compute a light front wave function for heavy vector mesons based on long distance matrix elements constrained by decay width analyses in the Non Relativistic QCD framework. Our approach provides a systematic expansion of the wave function in quark velocity. The first relativistic correction included in our calculation is found to be significant, and crucial for a good description of the HERA exclusive $\mathrm{J}/\psi$ production data. When looking at cross section ratios between nuclear and proton targets, the wave function dependence does not cancel out exactly. In particular the fully non-relativistic limit is found not to be a reliable approximation even in this ratio. The important role of the Melosh rotation to express the rest frame wave function on the light front is illustrated.

   hep-phnucl-thPRD(2020)·71 citations
7. 07*

   Rational terms in two-loop calculations

   Stefano Pozzorini🇨🇭 · Hantian Zhang🇨🇭 · Max F. Zoller🇨🇭

   We present an extension of the renormalisation procedure based on the R-operation in $D$ dimensions at two-loop level, in which the numerators of all Feynman diagrams can be constructed in four dimensions, and the rational terms stemming from the interplay of $(D-4)$-dimensional numerator parts and UV poles are fully reconstructed from a finite set of universal local counterterms. This represents an extension of the concept of rational terms of type $R_2$ to two loops. We provide a general method to compute one and two-loop rational counterterms from massive one-scale tadpole integrals. Finally, we present the full set of rational counterterms of UV origin for QED up to two-loop order.

   hep-phPoS(2019)·2 citations
8. 08*

   Non-thermal production of lepton asymmetry and dark matter in minimal seesaw with right handed neutrino induced Higgs potential

   Rome Samanta🇬🇧 · Anirban Biswas🇮🇳 · Sukannya Bhattacharya🇮🇳

   Within Type-I seesaw mechanism, Higgs mass can be dynamically generated via quantum effects of the right handed neutrinos assuming the potential is nearly conformal at the Ultra-Violet. The scenario, named as the "Neutrino Option" allows RH neutrino mass scale upto $M\lesssim$ $10^7$ GeV to be consistent with light neutrino masses, mixing and Higgs mass. Therefore, it is not consistent with standard hierarchical thermal leptogenesis. Parameter space for thermal resonant leptogenesis is highly constrained in this model. We point out that non-thermal pair production of RH neutrinos from inflaton decay corresponds in general to a mild degree of resonance in the CP asymmetry parameter and allows RH mass scale to be smaller more than by an order of magnitude than the thermal strong resonance case. Within the similar parameter space of thermal leptogenesis, RH neutrinos can also be produced from inflaton decay along with a Dark Matter having mass $M_{\mathrm{DM}}\lesssim$ 320 MeV. The main constraint in the latter scenario comes from the Ly$\alpha$ constraints on Dark Matter free streaming. We show in addition, that the Neutrino Option introduces a 'phantom window' for the RH mass scale, in which contrary to the usual scenarios, CP asymmetry parameter for leptogenesis decreases with the increase of the RH mass scale and minimally fine-tuned seesaw models naturally exhibit this `phantom window'.

   hep-phastro-ph.COJCAP(2021)·17 citations
9. 09*

   Pionium as a source of false events in the $K\to \pi \nu \bar{\nu }$ decays

   Peter Lichard🇨🇿

   We suggest that the decay modes of kaons with a pion and a pionium (${\pi }^{+}{\pi }^{-}$ atom) in the final state can constitute a not yet considered background to the very rare decay $K\to \pi \nu \bar{\nu }$. In fact, a part of pioniums may escape the decay region before decaying into two ${\pi }^0$s (or to ${\pi }^0{\pi }^0\gamma$ in the case of excited pionium). To illustrate the importance of this background, we show that it may even explain, under some assumptions, the unexpected $K_L$ decay events that appeared in the KOTO experiment.

   hep-phPRD(2020)·3 citations
10. 10*

    An introduction to strange stars

    V. P. Goncalves🇧🇷 · L. Lazzari🇧🇷

    The description of the heaviest neutron stars observed in Nature depends on the understanding of the physical concepts present in General Relativity and Quantum Chromodynamics. In this work, we review the basic concepts need to describe strange stars, constituted by up, down and strange quarks, which is one of the possible alternatives to describe the general properties of the most dense neutron stars. We will review the Bodmer-Witten-Terazawa hypothesis, which states that strange matter is absolutely stable in relation to ordinary nuclear matter, and discuss the basic properties that characterize strange stars. Our goal is to present the necessary concepts to understand this important theme of Astroparticles.

    hep-phastro-ph.HERev.Bras.Ens.Fis.(2020)·0 citations
11. 11*

    Leptogenesis and low-energy CP violation in a type-II-dominated left-right seesaw model

    Thomas Rink🇩🇪 · Werner Rodejohann🇩🇪 · Kai Schmitz🇨🇭

    We consider leptogenesis in a left-right-symmetric seesaw scenario in which neutrino mass generation and leptogenesis are dominated by the type-II seesaw term. Motivated by grand unification, we assume that the neutrino Dirac mass matrix is dominated by a single entry of the order of the top-quark mass, which leaves the low-energy phases of the lepton mixing matrix as the only sources of CP violation. Working in a regime where the triplet scalar predominantly decays into leptons, this results in a predictive scenario based on a minimal number of parameters. We perform a detailed analysis of the flavored Boltzmann equations within a revised density matrix framework and demonstrate that the observed baryon asymmetry can be successfully generated in this simple model. We point out that the significance of flavor effects is limited, and we discuss the implications for low-energy observables such as the Dirac CP phase and neutrinoless double beta decay.

    hep-phastro-ph.CONPB(2021)·12 citations
12. 12*

    Polarized electron-deuteron deep-inelastic scattering with spectator nucleon tagging

    W. Cosyn🇺🇸 · C. Weiss🇺🇸

    Background: DIS on the polarized deuteron with detection of a proton in the nuclear breakup region (spectator tagging) represents a unique method for extracting the neutron spin structure functions and studying nuclear modifications. The tagged proton momentum controls the nuclear configuration during the DIS process and enables a differential analysis of nuclear effects. Such measurements could be performed with the future electron-ion collider (EIC) and forward proton detectors if deuteron beam polarization could be achieved. Purpose: Develop theoretical framework for polarized deuteron DIS with spectator tagging. Formulate procedures for neutron spin structure extraction. Methods: A covariant spin density matrix formalism is used to describe general deuteron polarization in collider experiments (vector/tensor, pure/mixed). Light-front (LF) quantum mechanics is employed to factorize nuclear and nucleonic structure in the DIS process. A 4-dimensional representation of LF spin structure is used to construct the polarized deuteron LF wave function and efficiently evaluate the spin sums. Free neutron structure is extracted using the impulse approximation and analyticity in the tagged proton momentum (pole extrapolation). Results: General expressions of the polarized tagged DIS observables in collider experiments. Analytic and numerical study of the polarized deuteron LF spectral function and nucleon momentum distributions. Practical procedures for neutron spin structure extraction from the tagged deuteron spin asymmetries. Conclusions: Spectator tagging provides new tools for precise neutron spin structure measurements. D-wave depolarization and nuclear binding effects can be eliminated through the tagged proton momentum dependence. The methods can be extended to tensor-polarized observables, spin-orbit effects, and diffractive processes.

    hep-phnucl-exnucl-thPRC(2020)·29 citations
13. 13*

    The Clockwork Standard Model

    Yoo-Jin Kang🇰🇷 · Soonbin Kim🇰🇷 · Hyun Min Lee🇰🇷

    We consider various bulk fields with general dilaton couplings in the linear dilaton background in five dimensions as the continuum limit of clockwork models. We show that the localization of the zero modes of bulk fields and the mass gap in the KK spectrum depend not only on the bulk dilaton coupling, but also on the bulk mass parameter in the case of a bulk fermion. The consistency from universality and perturbativity of gauge couplings constrain the dilaton couplings to the brane-localized matter fields as well as the bulk gauge bosons. Constructing the Clockwork Standard Model (SM) in the linear dilaton background, we provide the necessary conditions for the bulk mass parameters for explaining the mass hierarchy and mixing for the SM fermions. We can introduce a sizable expansion parameter $\epsilon =e^{-\frac{2}{3}k{z}_c}$ for the realistic flavor structure in the quark sector without a fine-tuning in the bulk mass parameters, but at the expense of a large 5D Planck scale. On the other hand, we can use a smaller expansion parameter for lepton masses, in favor of the solution to the hierarchy problem of the Higgs mass parameter. We found that massive Kaluza-Klein (KK) gauge bosons and massive KK gravitons couple more strongly to light and heavy fermions, respectively, so there is a complementarity in the resonance researches for those KK modes at the LHC.

    hep-phhep-thJHEP(2020)·10 citations
14. 14*

    Deuteron and Antideuteron Coalescence in Heavy-Ion Collisions: Energy Dependence of the Formation Geometry

    Apiwit Kittiratpattana🇹🇭 · Michael Florian Wondrak🇩🇪 · Medina Hamzic🇧🇦 · Marcus Bleicher🇩🇪 · Christoph Herold🇹🇭 · Ayut Limphirat🇹🇭

    We investigate the collision energy dependence of deuteron and antideuteron emission in the RHIC-BES low- to mid-energy range $\sqrt{s_{NN}}=4.6-200$ GeV where the formation rate of antinuclei compared to nuclei is strongly suppressed. In the coalescence picture, this can be understood as bulk emission for nuclei in contrast to surface emission for antinuclei. By comparison with experimental data on the coalescence parameter $B_2$, we are able to extract the respective source geometries. This interpretation is further supported by results from the UrQMD transport model, and establishes the following picture: At low energies, nucleons freeze out over the total fireball volume, while antinucleons are annihilated inside the nucleon-rich fireball and can only freeze out on its surface. Towards higher energies, this annihilation effect becomes irrelevant (due to the decreasing baryochemical potential) and the system's freeze-out is driven by the mesons. Thus, the nucleon and antinucleon freeze-out distributions become similar with increasing energy.

    hep-phnucl-thEPJA(2020)·15 citations
15. 15*

    Collinear expansion for color singlet cross sections

    Markus A. Ebert🇺🇸 · Bernhard Mistlberger🇺🇸 · Gherardo Vita🇺🇸

    We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.

    hep-phnucl-thJHEP(2020)·27 citations
16. 16*

    N-jettiness beam functions at N3LO

    Markus Ebert🇺🇸 · Bernhard Mistlberger🇺🇸 · Gherardo Vita🇺🇸

    We present the first complete calculation for the quark and gluon $N$-jettiness (${\mathrm{T}}_N$) beam functions at next-to-next-to-next-to-leading order (N${}^3$LO) in perturbative QCD. Our calculation is based on an expansion of the differential Higgs boson and Drell-Yan production cross sections about their collinear limit. This method allows us to employ cutting edge techniques for the computation of cross sections to extract the universal building blocks in question. The class of functions appearing in the matching coefficents for all channels includes iterated integrals with non-rational kernels, thus going beyond the one of harmonic polylogarithms. Our results are a key step in extending the ${\mathrm{T}}_N$ subtraction methods to N${}^3$LO, and to resum ${\mathrm{T}}_N$ distributions at N${}^3$LL${}^{\prime }$ accuracy both for quark as well as for gluon initiated processes.

    hep-phnucl-thJHEP(2020)·60 citations
17. 17*

    Double Cover of Modular $S_4$ for Flavour Model Building

    P. P. Novichkov🇮🇹 · J. T. Penedo🇵🇹 · S. T. Petcov🇮🇹

    We develop the formalism of the finite modular group ${\Gamma }_4^{\prime }\equiv S_4^{\prime }$, a double cover of the modular permutation group ${\Gamma }_4\simeq S_4$, for theories of flavour. The integer weight $k>0$ of the level 4 modular forms indispensable for the formalism can be even or odd. We explicitly construct the lowest-weight ($k=1$) modular forms in terms of two Jacobi theta constants, denoted as $\epsilon (\tau )$ and $\theta (\tau )$, $\tau$ being the modulus. We show that these forms furnish a 3D representation of $S_4^{\prime }$ not present for $S_4$. Having derived the $S_4^{\prime }$ multiplication rules and Clebsch-Gordan coefficients, we construct multiplets of modular forms of weights up to $k=10$. These are expressed as polynomials in $\epsilon$ and $\theta$, bypassing the need to search for non-linear constraints. We further show that within $S_4^{\prime }$ there are two options to define the (generalised) CP transformation and we discuss the possible residual symmetries in theories based on modular and CP invariance. Finally, we provide two examples of application of our results, constructing phenomenologically viable lepton flavour models.

    hep-phhep-thNPB(2021)·136 citations
18. 18*

    No Miracle in Gravity Portals

    Fedor Bezrukov🇬🇧 · Sergey Demidov🇷🇺 · Dmitry Gorbunov🇷🇺

    The idea of dark matter particles coupled only gravitationally is minimalist yet viable. Assuming an additional $Z_2$-breaking linear coupling of scalar curvature to the dark matter scalar (gravity portal) Refs. arXiv:1603.03696 and arXiv:1611.00725 claimed a strong parametric growth of the dark matter particle decay rate with its mass, which implies pronounced phenomenological signatures for the model. This peculiarity was attributed by the authors to the enhancement due to the presence of longitudinal gauge bosons in the final state. Quite unfortunately there were overlooked cancellations in the tree-level amplitudes. There is no miracle: all perturbative decay rates are suppressed by the strong coupling scale.

    hep-ph4 citations
19. 19*

    Transverse momentum dependent PDFs at N${}^3$LO

    Markus A. Ebert🇺🇸 · Bernhard Mistlberger🇺🇸 · Gherardo Vita🇺🇸

    We compute the quark and gluon transverse momentum dependent parton distribution functions at next-to-next-to-next-to-leading order (N${}^3$LO) in perturbative QCD. Our calculation is based on an expansion of the differential Higgs boson and Drell-Yan production cross sections about their collinear limit. This method allows us to employ cutting edge techniques for the computation of cross sections to extract the universal building blocks in question. The corresponding perturbative matching kernels for all channels are expressed in terms of simple harmonic polylogarithms up to weight five. As a byproduct, we confirm a previous computation of the soft function for transverse momentum factorization at N${}^3$LO. Our results are the last missing ingredient to extend the $q_T$ subtraction methods to N${}^3$LO and to obtain resummed $q_T$ spectra at N${}^3$LL${}^{\prime }$ accuracy both for gluon as well as for quark initiated processes.

    hep-phnucl-thJHEP(2020)·148 citations
20. 20*

    Viability of slow-roll inflation in light of the non-zero k_min measured in the CMB power spectrum

    Jingwei Liu🇺🇸 · Fulvio Melia🇺🇸

    Slow-roll inflation may simultaneously solve the horizon problem and generate a near scale-free fluctuation spectrum P(k). These two processes are intimately connected via the initiation and duration of the inflationary phase. But a recent study based on the latest Planck release suggests that P(k) has a hard cutoff, k_min > 0, inconsistent with this conventional picture. Here we demonstrate quantitatively that most---perhaps all---slow-roll inflationary models fail to accommodate this minimum cutoff. We show that the small parameter `epsilon' must be > 0.9 throughout the inflationary period to comply with the data, seriously violating the slow-roll approximation. Models with such an epsilon predict extremely red spectral indices, at odds with the measured value. We also consider extensions to the basic picture (suggested by several earlier workers) by adding a kinetic-dominated or radiation-dominated phase preceding the slow-roll expansion. Our approach differs from previously published treatments principally because we require these modifications to---not only fit the measured fluctuation spectrum, but to simultaneously also---fix the horizon problem. We show, however, that even such measures preclude a joint resolution of the horizon problem and the missing correlations at large angles.

    ↳ astro-ph.COgr-qchep-phProc.Roy.Soc.Lond.A(2020)·19 citations
21. 21*

    Graviballs and Dark Matter

    B. Guiot🇨🇱 · A. Borquez🇨🇱 · A. Deur🇺🇸 · K. Werner🇫🇷

    We investigate the possible existence of graviballs, a system of bound gravitons, and show that two gravitons can be bound together by their gravitational interaction. This idea connects to black hole formation by a high-energy $2\to N$ scattering and to the gravitational geon studied by Brill and Hartle. Our calculations rely on the formalism and techniques of quantum field theory, specifically on low-energy quantum gravity. By solving numerically the relativistic equations of motion, we have access to the space-time dynamics of the (2-gravitons) graviball formation. We argue that the graviball is a viable dark matter candidate and we compute the associated gravitational lensing.

    ↳ gr-qcastro-ph.GAhep-phJHEP(2020)·13 citations
22. 22*

    Relic gravitons from stiff curvature perturbations

    Massimo Giovannini🇨🇭

    The tensor modes reentering the Hubble radius when the plasma is dominated by a stiff fluid lead to a spectral energy density whose blue slope depends on the total post-inflationary sound speed. This result gets however corrected by a secondary (gauge-dependent) term coming from the curvature inhomogeneities that reenter all along the same stage of expansion. In comparison with the first-order result, the secondary contribution is shown to be always suppressed inside the sound horizon and its effect on the total spectral energy density of the relic gravitons is therefore negligible for all phenomenological purposes. It is also suggested that the effective anisotropic stress of the curvature inhomogeneities can be obtained from the functional derivative of the second-order action of curvature inhomogeneities with respect to the background metric.

    ↳ gr-qcastro-ph.COhep-phhep-thPLB(2020)·13 citations
23. 23*

    Search for hidden-photon cold dark matter using a K-band cryogenic receiver

    Nozomu Tomita🇯🇵 · Shugo Oguri🇯🇵 · Yoshizumi Inoue🇯🇵 · Makoto Minowa🇯🇵 · Taketo Nagasaki🇯🇵 · Jun'ya Suzuki🇯🇵 · Osamu Tajima🇯🇵

    We search for hidden-photon cold dark matter (HP-CDM) using a spectroscopic system in a K-band frequency range. Our system comprises a planar metal plate and cryogenic receiver. This is the first time a cryogenic receiver has been used in the search for HP-CDM. Such use helps reduce thermal noise. We recorded data for 9.3 hours using an effective aperture area of 14.8 cm${}^2$. No signal was found in the data. We set upper limits for the parameter of mixing between the photon and HP-CDM in the mass range from 115.79 to 115.85 $\mu$eV, $\chi <1.8$-$4.3\times 10^{-10}$, at a 95% confidence level. This is the most stringent upper limit obtained to date in the considered mass range.

    ↳ hep-exhep-phphysics.ins-detJCAP(2020)·31 citations
24. 24*

    Factorial cumulants from global baryon number conservation

    Michał Barej🇵🇱 · Adam Bzdak🇵🇱

    The proton, antiproton and mixed proton-antiproton factorial cumulants originating from the global conservation of baryon number are calculated analytically up to the sixth order. Our results can be directly tested in experiments.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2020)·10 citations
25. 25*

    Eclectic flavor scheme from ten-dimensional string theory -- I. Basic results

    Hans Peter Nilles🇩🇪 · Saul Ramos-Sanchez🇲🇽 · Patrick K.S. Vaudrevange🇩🇪

    In a consistent top-down approach based on orbifold compactifications, modular and traditional flavor symmetries combine nontrivially to the so-called eclectic flavor symmetry. We extend this scheme from two extra dimensions, discussed previously, to the six extra dimensions of string theory. By doing so, new insights on the nature of CP and its spontaneous breaking emerge. Moreover, we identify a new interpretation of R-symmetries as unbroken remnants from modular symmetries that are associated with geometrically stabilized complex structure moduli. Hence, all symmetries (i.e. modular, traditional flavor, CP and R) share a common origin in string theory: on a technical level, they are given by outer automorphisms of the Narain space group. The eclectic top-down approach leads to a very restrictive scheme with high predictive power. It remains a challenge to connect this with existing bottom-up constructions of modular flavor symmetry.

    ↳ hep-thhep-phPLB(2020)·72 citations
26. 26*

    Strange mesons in strong magnetic fields

    Amruta Mishra🇮🇳 · S. P. Misra🇮🇳

    The masses of the strange mesons ($K$, $K^{\ast }$ and $\varphi$) are investigated in the presence of strong magnetic fields. The changes in the masses of these mesons arise from the mixing of the pseusdoscalar and vector mesons in the presence of a magnetic field. For the charged mesons, these mass modifications are in addition to the contributions from the lowest Landau energy levels to their masses. The decay widths, $\varphi \to K\bar{K}$ and $K^{\ast }\to K\pi$, in the presence of the magnetic field are studied using a field theoretic model of composite hadrons with constituent quarks/antiquarks. The model uses the free Dirac Hamiltonian in terms of the constituent quark fields as the light quark antiquark pair creation term and explicit constructions for the meson states in terms of the constituent quarks and anitiquarks to study the decay processes. The study of the masses and decay widths of the strange mesons in strong magnetic fields can have observable consequences on the production of the open and hidden strange mesons in the peripheral ultra high energy collisions at LHC, where the created magnetic field can be huge.

    ↳ nucl-thhep-phIJMPE(2021)·20 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.