Wed·Jan 1, 2020Wednesday·January 1, 2020

1. 01*

   Analytic Properties of Triangle Feynman Diagrams in Quantum Field Theory

   Dmitri Melikhov🇷🇺

   We discuss dispersion representations for the triangle diagram $F(p_1^2,p_2^2,q^2)$, the single dispersion representation in $q^2$ and the double dispersion representation in $p_1^2$ and $p_2^2$, with special emphasis on the appearance of the anomalous singularities and the anomalous cuts in these representations.

   hep-phParticles(2020)·3 citations
2. 02*

   Sensitivity of EDM experiments in paramagnetic atoms and molecules to hadronic CP violation

   V. V. Flambaum🇦🇺 · M. Pospelov🇺🇸 · A. Ritz🇨🇦 · Y. V. Stadnik🇩🇪

   Experiments searching for the electric dipole moment (EDM) of the electron $d_e$ utilise atomic/molecular states with one or more uncompensated electron spins, and these paramagnetic systems have recently achieved remarkable sensitivity to $d_e$. If the source of $CP$ violation resides entirely in the hadronic sector, the two-photon exchange processes between electrons and the nucleus induce $CP$-odd semileptonic interactions, parametrised by the Wilson coefficient $C_{SP}$, and provide the dominant source of EDMs in paramagnetic systems instead of $d_e$. We evaluate the $C_{SP}$ coefficients induced by the leading hadronic sources of $CP$ violation, namely nucleon EDMs and $CP$-odd pion-nucleon couplings, by calculating the nucleon-number-enhanced $CP$-odd nuclear scalar polarisability, employing chiral perturbation theory at the nucleon level and the Fermi-gas model for the nucleus. This allows us to translate the ACME EDM limits from paramagnetic ThO into novel independent constraints on the QCD theta term $|\bar{\theta }|<3\times 10^{-8}$, proton EDM $|d_p|<2\times 10^{-23}e\mathrm{cm}$, isoscalar $CP$-odd pion-nucleon coupling $|{\bar{g}}_{\pi NN}^{(1)}|<4\times 10^{-10}$, and colour EDMs of quarks $|{\tilde{d}}_u-{\tilde{d}}_d|<2\times 10^{-24}\mathrm{cm}$. We note that further experimental progress with EDM experiments in paramagnetic systems may allow them to rival the sensitivity of EDM experiments with neutrons and diamagnetic atoms to these quantities.

   hep-phnucl-thphysics.atom-phPRD(2020)·63 citations
3. 03*

   LHC probes of the 10 TeV scale

   Bogdan A. Dobrescu🇺🇸

   The usual range of new particle masses, up to a few TeV, searched for at the LHC may be substantially extended if ultraheavy diquark particles exist. A diquark scalar, $S_{uu}$, that interacts perturbatively with two up quarks may be as heavy as 10 TeV and would still produce tens of spectacular events at the 14 TeV LHC. It is shown here that an ultraheavy $S_{uu}$ could be discovered through final states of very high energy in various channels, especially if the diquark can decay into other new heavy particles. Examples include cascade decays of $S_{uu}$ via a second scalar produced in pairs, which leads to two dijet resonances, or to more exotic signals with top quarks, Higgs bosons, electroweak bosons, and high-$p_T$ jets. Another possibility is that the diquark decays into a vectorlike quark of multi-TeV mass and a top or up quark. Signal events include one or two highly boosted top quarks and a Higgs boson or a $Z$, without counterparts containing top antiquarks. Similarly, direct decays of the diquark into $tj$ or $tt$ with leptonic top decays involve only positively charged leptons.

   hep-phhep-ex17 citations
4. 04*

   Using the Beth-Uhlenbeck approach to describe the kaon to pion ratio in a 2+1 flavor PNJL model

   D. Blaschke🇵🇱 · A. Friesen🇷🇺 · Yu. Kalinovsky🇷🇺 · A. Radzhabov🇷🇺

   The kaon to pion ratios are discussed in the framework of a 2+1 flavor PNJL model. In order to interpret the behaviour of bound states in medium the Beth-Uhlenbeck approach is used. It is shown that in terms of phase shifts in the K+ channel an additional low-energy mode could appear as a bound state in medium since the masses of the quark constituents are different. The comparison with experimental data for the ratios is performed and the influence of the anomalous mode to the "horn" effect in the K+/pi+ ratio is discussed.

   hep-phParticles(2020)·3 citations
5. 05*

   Lepton Flavor Mixing and CP Violation in the Minimal Type-(I+II) Seesaw Model with a Modular $A_4$ Symmetry

   Xin Wang🇨🇳

   In this paper, we study the implications of the modular $A_4^{}$ flavor symmetry in constructing a supersymmetric minimal type-(I+II) seesaw model, in which only one right-handed neutrino and two Higgs triplets are introduced to account for the tiny neutrino masses, flavor mixing and CP violation. The right-handed neutrino as well as the Higgs triplets in this model are assigned into the trivial one-dimensional irreducible representation of the modular group $A_4^{}$. We show that the individual contributions to the neutrino masses from the right-handed neutrino and the Higgs triplet are comparable. We also find that the neutrino mass matrix can possess an approximate $\mu -\tau$ reflection symmetry for some specific values of free model parameters. Moreover, our model predicts relatively large masses of three light neutrinos, thus can be easily tested in future neutrino experiments.

   hep-phNPB(2020)·100 citations
6. 06*

   Can Lorentz Invariance Violation affect the Sensitivity of Deep Underground Neutrino Experiment?

   Sanjib Kumar Agarwalla🇮🇳 · Mehedi Masud🇮🇳

   We examine the impact of Lorentz Invariance Violation (LIV) in measuring the octant of ${\theta }_{23}$ and CP phases in the context of the Deep Underground Neutrino Experiment (DUNE). We consider the CPT-violating LIV parameters involving $e-\mu$ ($a_{e\mu }$) and $e-\tau$ ($a_{e\tau }$) flavors, which induce an additional interference term in neutrino and antineutrino appearance probabilities. This new interference term depends on both the standard CP phase $\delta$ and the new dynamical CP phase ${\phi }_{e\mu }$/${\phi }_{e\tau }$, giving rise to new degeneracies among (${\theta }_{23}$, $\delta$, $\phi$). Taking one LIV parameter at-a-time and considering a small value of $|a_{e\mu }|=|a_{e\tau }|=5\times 10^{-24}$ GeV, we find that the octant discovery potential of DUNE gets substantially deteriorated for unfavorable combinations of $\delta$ and ${\phi }_{e\mu }$/${\phi }_{e\tau }$. The octant of ${\theta }_{23}$ can only be resolved at $3\sigma$ if the true value of ${\sin }^2{\theta }_{23}\lesssim 0.42$ or $\gtrsim 0.62$ for any choices of $\delta$ and $\phi$. Interestingly, we also observe that when both the LIV parameters $a_{e\mu }$ and $a_{e\tau }$ are present together, they cancel out the impact of each other to a significant extent, allowing DUNE to largely regain its octant resolution capability. We also reconstruct the CP phases $\delta$ and ${\phi }_{e\mu }$/${\phi }_{e\tau }$. The typical $1\sigma$ uncertainty on $\delta$ is $10^{\circ }$ to $15^{\circ }$ and the same on ${\phi }_{e\mu }$/${\phi }_{e\tau }$ is $25^{\circ }$ to $30^{\circ }$ depending on the choices of their true values.

   hep-phhep-exphysics.ins-detEPJC(2020)·24 citations
7. 07*

   Neutrino evolution and quantum decoherence

   Konstantin Stankevich🇷🇺 · Alexander Studenikin🇷🇺

   Neutrino interactions with an external environment can in influence the neutrino oscillation pattern and the oscillations can be damped as a result of the neutrino quantum decoherence. In particular, the quantum decoherence of neutrino states engendered by the neutrino radiative decay accounting for the nonstandard interactions (NSI) leads to the suppression of flavor neutrino oscillations in the solar neutrino fluxes.

   hep-phJ.Phys.Conf.Ser.(2020)·3 citations
8. 08*

   The effect of neutrino quantum decoherence

   Konstantin Stankevich🇷🇺 · Alexander Studenikin🇷🇺

   The neutrino oscillation patterns can be modified by neutrino interactions with external environments including electromagnetic fields that can influence on neutrinos in the case neutrinos have nonzero electromagnetic properties [1]. The phenomenon of neutrino oscillations can proceed only in the case of the coherent superposition of neutrino mass states. An external environment can modify a neutrino evolution in a way that conditions for the coherent superposition of neutrino mass states are violated. Such a violation is called quantum decoherence of neutrino states and leads to the suppression of flavor neutrino oscillations [2, 3]. Note that neutrino decoherence appeared due to the wave separation of different mass states is usually not related to quantum neutrino decoherence, the effect that is not considered below. We consider the neutrino quantum decoherence due to neutrino radiative decay in the presence of an electron medium and radiation field. The corresponding damping of neutrino oscillations is calculated.

   hep-phPoS(2020)·1 citation
9. 09*

   Effects of heavy Majorana neutrinos on lepton flavor violating processes

   G. Hernández-Tomé🇪🇸 · J. I. Illana🇪🇸 · G. López Castro🇲🇽 · M. Masip🇪🇸 · P. Roig🇲🇽

   The observation of lepton flavor violating processes at colliders could be a clear signal of a non-minimal neutrino sector. We define a 5-parameter model with a pair of TeV fermion singlets and arbitrary mixings with the three active neutrino flavors. Then we analyze several flavor violating transitions ($\ell \to {\ell }^{\prime }\gamma ,{\ell }^{\prime }{\ell }^{\prime \prime }{\bar{\ell }}^{\prime \prime \prime }$ or $\mu -e$ conversions in nuclei) and $Z\to \bar{\ell }{\ell }^{\prime }$ decays induced by the presence of heavy neutrinos. In particular, we calculate all the one-loop contributions to these processes and present their analytic expressions. We focus on the genuine effects of the heavy Majorana masses, comparing the results in that case with the ones obtained when the two heavy neutrinos define a Dirac field. Finally, we use our results to update the bounds on the heavy-light mixings in the neutrino sector.

   hep-phPRD(2020)·47 citations
10. 10*

    Infrared structure of $SU(N)\times U(1)$ gauge theory to three loops

    A. H. Ajjath · Pooja Mukherjee🇮🇳 · V. Ravindran🇮🇳

    We study the infrared (IR) structure of $SU(N)\times U(1)$ (QCD $\times$ QED) gauge theory with $n_f$ quarks and $n_l$ leptons within the framework of perturbation theory. In particular, we unravel the IR structure of the form factors and inclusive real emission cross sections that contribute to inclusive production of color neutral states, such as a pair of leptons or single W/Z in Drell-Yan processes and a Higgs boson in bottom quark annihilation, in Large Hadron Collider (LHC) in the threshold limit. Explicit computation of the relevant form factors to third order and the use of Sudakov's $K+G$ equation in $SU(N)\times U(1)$ gauge theory demonstrate the universality of the cusp anomalous dimensions ($A_I,I=q,b$). The abelianization rules that relate $A_I$ of $SU(N)$ with those from $U(1)$ and $SU(N)\times U(1)$ can be used to predict the soft distribution that results from the soft gluon emission subprocesses in the threshold limit. Using the latter and the third order form factors, we can obtain the collinear anomalous dimensions ($B_I$ ) and the renormalisation constant $Z_b$ to third order in perturbation theory. The form factors, the process independent soft distribution functions can be used to predict fixed and resummed inclusive cross sections to third order in couplings and in leading logarithmic approximation respectively.

    hep-phJHEP(2020)·16 citations
11. 11*

    Hadron structure and parton branching beyond collinear approximations

    F Hautmann🇬🇧

    We briefly illustrate recent developments in the parton branching formulation of TMD evolution and their impact on precision measurements in high-energy hadronic collisions.

    hep-ph1 citation
12. 12*

    Neutrino Non-Standard Interactions via Light Scalars in the Earth, Sun, Supernovae and the Early Universe

    K. S. Babu🇺🇸 · Garv Chauhan🇺🇸 · P. S. Bhupal Dev🇺🇸

    Non-standard interactions (NSI) of neutrinos with matter mediated by a scalar field would induce medium-dependent neutrino masses which can modify oscillation probabilities. Generating observable effects requires an ultra-light scalar mediator. We derive general expressions for the scalar NSI using techniques of quantum field theory at finite density and temperature, including the long-range force effects, and discuss various limiting cases applicable to the neutrino propagation in different media, such as the Earth, Sun, supernovae and early Universe. We also analyze various terrestrial and space-based experimental constraints, as well as astrophysical and cosmological constraints on these NSI parameters, applicable to either Dirac or Majorana neutrinos. By combining all these constraints, we show that observable scalar NSI effects, although precluded in terrestrial experiments, are still possible in future solar and supernovae neutrino data, and in cosmological observations such as cosmic microwave background and big bang nucleosynthesis data.

    hep-phastro-ph.COhep-exPRD(2020)·106 citations
13. 13*

    Axionic excitation from QCD Condensate

    Chi Xiong🇨🇳

    A complex order parameter is used for describing inhomogeneous quark condensate and its phase is decomposed into a regular part and a singular part. An emergent gauge symmetry is found to connect these two parts. The singular part plays the role of an emergent gauge field while the regular part can be considered as an axionic excitation, provided that the chromoelectric flux tube is capable of inducing a vortex configuration in the quark condensate, with the help of axial anomaly.

    hep-phhep-thCommun.Theor.Phys.(2025)·1 citation
14. 14*

    Exploring leptoquark effects in hyperon and kaon decays with missing energy

    Jhih-Ying Su🇹🇼 · Jusak Tandean🇹🇼

    We entertain the possibility that scalar leptoquarks (LQs) generate consequential effects on the strangeness-changing decays of hyperons and kaons involving missing energy carried away by a pair of invisible fermions. Although such processes have suppressed rates in the standard model (SM), they could get significant enhancement in the presence of the LQs. In order to respect the available data on the kaon modes $K\to \pi \nu \bar{\nu }$ and increase the rates of the hyperon decays substantially at the same time, two different scalar LQs are needed. If the LQs have Yukawa couplings solely to SM fermions, we find that the hyperon rates cannot attain values within the reach of ongoing or near-future experiments because of the combined constraints from the measurements on kaon mixing and lepton-flavor-violating processes. However, if we include light right-handed neutrinos in the LQ interactions, their contributions can evade the leading restrictions and translate into hyperon rates which may be big enough to be probed by upcoming searches. Thus, these hyperon modes could provide a new avenue for seeking sterile neutrinos.

    hep-phhep-exPRD(2020)·12 citations
15. 15*

    Majorana phases in high-scale mixings unification hypotheses

    S.S. AbdusSalam🇮🇷 · M.Z. Abyaneh🇮🇷 · F. Ghelichkhani🇮🇷 · M. Noormandipour🇮🇷

    For addressing the remarkable difference between neutrino and quark mixings, high-scale mixings relations (HSMR) or unification (HSMU) hypothe\ ses were proposed. These phenomenology frameworks have been explored with respect to bounds from neutrino oscillations and relevant cosmologic\ al data. However there are caveats with regards to assessing the hypotheses' compatibility with data in a statistically robust and convergent \ manner because most analysis employ a few sample of points in model parameters' space. A remedy could be achieved by using Bayesian algorithms\ for the parameters' space exploration. Using this approach, we made global fits of the HSMU and HSMR models to data and find compatible param\ eter regions, including for Majorana phases. The posterior samples could be used for studying correlations between neutrino observables and pr\ ospects for updates of related experiments.

    hep-phInt.J.Mod.Phys.A(2021)·4 citations
16. 16*

    Loops and trees in generic EFTs

    Nathaniel Craig🇺🇸 · Minyuan Jiang🇨🇳 · Ying-Ying Li🇺🇸 · Dave Sutherland🇮🇹

    We consider aspects of tree and one-loop behavior in a generic 4d EFT of massless scalars, fermions, and vectors, with a particular eye to the high-energy limit of the Standard Model EFT at operator dimensions 6 and 8. First, we classify the possible Lorentz structures of operators and the subset of these that can arise at tree-level in a weakly coupled UV completion, extending the tree/loop classification through dimension 8 using functional methods. Second, we investigate how operators contribute to tree and one-loop helicity amplitudes, exploring the impact of non-renormalization theorems through dimension 8. We further observe that many dimension 6 contributions to helicity amplitudes, including rational parts, vanish exactly at one-loop level. This suggests the impact of helicity selection rules extends beyond one loop in non-supersymmetric EFTs.

    hep-phhep-thJHEP(2020)·92 citations
17. 17*

    Stringy Newton Gravity with $H$-flux

    Kyoungho Cho🇰🇷 · Kevin Morand🇰🇷 · Jeong-Hyuck Park🇰🇷

    A Symmetry Principle has been shown to augment unambiguously the Einstein Field Equations, promoting the whole closed-string massless NS-NS sector to stringy graviton fields. Here we consider its weak field approximation, take a non-relativistic limit, and derive the stringy augmentation of Newton Gravity: \[ \begin{array}{lll} {\bf{\nabla}^{2}\Phi}=4\pi G \rho+\bf{H}{\bf{\cdot}}\bf{H}\,, \quad&\qquad\bf{\nabla}\bf{\cdot}\bf{H}=0\,, \quad&\qquad {\bf{\nabla}\bf{\times}\bf{H}}=4\pi G\, \bf{K}\,. \end{array} \] Not only the mass density $\rho$ but also the current density $\mathbf{K}$ is intrinsic to matter. Sourcing $\mathbf{H}$ which is of NS-NS $H$-flux origin, $\mathbf{K}$ is nontrivial if the matter is `stringy'. $\mathbf{H}$ contributes quadratically to the Newton potential, but otherwise is decoupled from the point particle dynamics, i.e. $\ddot{\mathbf{x}}=-\nabla \mathbf{\Phi }$. We define `stringization' analogous to magnetization and discuss regular as well as monopole-like singular solutions.

    ↳ hep-thastro-ph.GAgr-qchep-phPRD(2020)·6 citations
18. 18*

    Useful relations among the generators in the defining and adjoint representations of SU(N)

    Howard E. Haber🇺🇸

    There are numerous relations among the generators in the defining and adjoint representations of SU(N). These include Casimir operators, formulae for traces of products of generators, etc. Due to the existence of the completely symmetric tensor $d_{abc}$ that arises in the study of the SU(N) Lie algebra, one can also consider relations that involve the adjoint representation matrix, $(D^a{)}_{bc}=d_{abc}$. In this review, we summarize many useful relations satisfied by the defining and adjoint representation matrices of SU(N). A few relations special to the case of N=3 are highlighted.

    ↳ math-phhep-phmath.MPSciPost Phys.Lect.Notes(2021)·68 citations
19. 19*

    EFT Compatible PBHs: Effective Spawning of the Seeds for Primordial Black Holes during Inflation

    Amjad Ashoorioon🇮🇷 · Abasalt Rostami🇮🇷 · Javad T. Firouzjaee🇮🇷

    Most of the inflationary scenarios that try to explain the origin of Primordial Black Holes (PBHs) from the enhancements of the power spectrum to values of order one, at the relevant scales, run into clashes with the Effective Field Theory (EFT) criteria or fail to enhance the power spectrum to such large amplitudes. In this paper, we unravel a mechanism for enhancing the power spectrum during inflation that does not use the flattening of the potential or reduction of the sound speed of scalar perturbations. The mechanism is based on this observation in the formalism of Extended EFT of inflation (EEFToI) with the sixth order polynomial dispersion relation for scalar perturbations that if the quartic coefficient in the dispersion relation is negative and smaller than a certain threshold, the amplitude of the power spectrum is enhanced substantially. The instability mechanism must arrange to kick in at the scales of interest related to the mass of the PBHs one would like to produce, which can be ten(s) of solar mass PBHs, suitable for LIGO events, or $10^{-17}-10^{-13}$ solar mass PBHs, which can comprise the whole dark matter energy density. We argue that the strong coupling is avoided for the range of parameters that the mechanisms enhance the power spectrum to the required amount.

    ↳ astro-ph.COgr-qchep-phhep-thJHEP(2021)·95 citations
20. 20*

    Horizonless ultracompact objects and dark matter in quadratic gravity

    Alberto Salvio🇮🇹 · Hardi Veermäe🇪🇪

    We show that in quadratic gravity sufficiently light objects must be horizonless and construct explicit analytic examples of horizonless ultracompact objects (UCOs), which are more compact than Schwarzschild black holes. Due to the quadratic terms, gravity becomes soft and eventually vanishes in the high-energy limit leading to a "linearization mechanism": light objects can be described by the linearized theory when their Schwarzschild radius is smaller than the Compton wavelength of the new gravitational degrees of freedom. As a result, we can analytically describe UCOs with a mass-to-radius ratio higher than for a Schwarzschild black hole. The corresponding spacetime is regular everywhere. We show that the Ostrogradsky instabilities can be avoided and discuss the relation with the Higgs vacuum metastability. Due to the lack of a horizon, light UCOs do not evaporate. Therefore, they may play the role of dark matter. We briefly discuss their phenomenology.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2020)·22 citations
21. 21*

    An Effective Field Theory of Quantum Mechanical Black Hole Horizons

    Walter D. Goldberger🇺🇸 · Ira Z. Rothstein🇺🇸

    We develop an effective theory which describes black holes with quantum mechanical horizons that is valid at scales long compared to the Schwarzschild radius but short compared to the lifetime of the black hole. Our formalism allows one to calculate the quantum mechanical effects in scattering processes involving black hole asymptotic states. We point out that the EFT Wightman functions which describe Hawking radiation in the Unruh vacuum are not Planck suppressed and are actually {\it enhanced} relative to those in the Boulware vacuum, for which such radiation is absent. We elaborate on this point showing how the non-Planck suppressed effects of Hawking radiation cancel in classical observables.

    ↳ hep-thgr-qchep-phJHEP(2020)·49 citations
22. 22*

    Fluctuation dynamics in a relativistic fluid with a critical point

    Xin An🇺🇸 · Gokce Basar🇺🇸 · Mikhail Stephanov🇺🇸 · Ho-Ung Yee🇺🇸

    To describe dynamics of bulk and fluctuations near the QCD critical point we develop general relativistic fluctuation formalism for a fluid carrying baryon charge. Feedback of fluctuations modifies hydrodynamic coefficients including bulk viscosity and conductivity and introduces nonlocal and non-instantaneous terms in constitutive equations. We perform necessary ultraviolet (short-distance) renormalization to obtain cutoff independent deterministic equations suitable for numerical implementation. We use the equations to calculate the universal non-analytic small-frequency dependence of transport coefficients due to fluctuations (long-time tails). Focusing on the critical mode we show how this general formalism matches existing Hydro+ description of fluctuations near the QCD critical point and nontrivially extends it inside and outside of the critical region.

    ↳ hep-thcond-mat.stat-mechhep-phnucl-thPRC(2020)·70 citations
23. 23*

    The Four-Loop Cusp Anomalous Dimension from the $\mathcal{N}=4$ Sudakov Form Factor

    Tobias Huber🇩🇪 · Andreas von Manteuffel🇺🇸 · Erik Panzer🇬🇧 · Robert M. Schabinger🇺🇸 · Gang Yang🇨🇳

    We present an analytic derivation of the full four-loop cusp anomalous dimension of $\mathcal{N}=4$ supersymmetric Yang-Mills theory from the Sudakov form factor. To extract the cusp anomalous dimension, we calculate the ${ϵ}^{-2}$ pole of the form factor using parametric integrations of finite integrals. We provide uniformly transcendental results for the master integrals through to weight six and confirm a very recent independent analytic result for the full four-loop cusp anomalous dimension of the $\mathcal{N}=4$ model.

    ↳ hep-thhep-phPLB(2020)·51 citations
24. 24*

    Charting the European Course to the High-Energy Frontier

    U. Amaldi · E. Aslanides · R. Barate · C. Benvenuti · P. Bloch · T. Camporesi · A. David · D. Denegri · M. Diemoz · L. Di Lella · G. Dissertori · N. Doble and 41 other authors

    We review the capabilities of two projects that have been proposed as the next major European facility, for consideration in the upcoming update of the European Strategy for Particle Physics: CLIC and FCC. We focus on their physics potentials and emphasise the key differences between the linear or circular approaches. We stress the uniqueness of the FCC-ee programme for precision electroweak physics at the $Z$ peak and the $WW$ threshold, as well as its unequalled statistics for Higgs physics and high accuracy for observing possible new phenomena in Higgs and $Z$ decays, whereas CLIC and FCC-ee offer similar capabilities near the $t\overline{t}$ threshold. Whilst CLIC offers the possibility of energy upgrades to 1500 and 3000 GeV, FCC-ee paves the way for FCC-hh. The latter offers unique capabilities for making direct or indirect discoveries in a new energy range, and has the highest sensitivity to the self-couplings of the Higgs boson and any anomalous couplings. We consider the FCC programme to be the best option to maintain Europe's place at the high-energy frontier during the coming decades.

    ↳ hep-exhep-phphysics.acc-ph8 citations
25. 25*

    Higher Anomalies, Higher Symmetries, and Cobordisms II: Lorentz Symmetry Extension and Enriched Bosonic/Fermionic Quantum Gauge Theory

    Zheyan Wan🇨🇳 · Juven Wang🇺🇸 · Yunqin Zheng🇺🇸

    We systematically study Lorentz symmetry extensions in quantum field theories (QFTs) and their 't Hooft anomalies via cobordism. The total symmetry $G^{\prime }$ can be expressed in terms of the extension of Lorentz symmetry $G_L$ by an internal global symmetry $G$ as $1\to G\to G^{\prime }\to G_L\to 1$. By enumerating all possible $G_L$ and symmetry extensions, other than the familiar SO/Spin/O/Pin${}^{\pm }$ groups, we introduce a new EPin group (in contrast to DPin), and provide natural physical interpretations to exotic groups E($d$), EPin($d$), (SU(2)$\times$E(d))/${\mathbb{Z}}_2$, (SU(2)$\times$EPin(d))/${\mathbb{Z}}_2^{\pm }$, etc. By Adams spectral sequence, we systematically classify all possible $d$d Symmetry Protected Topological states (SPTs as invertible TQFTs) and $(d-1)$d 't Hooft anomalies of QFTs by co/bordism groups and invariants in $d\le 5$. We further gauge the internal $G$, and study Lorentz symmetry-enriched Yang-Mills theory with discrete theta terms given by gauged SPTs. We not only enlist familiar bosonic Yang-Mills but also discover new fermionic Yang-Mills theories (when $G_L$ contains a graded fermion parity ${\mathbb{Z}}_2^F$), applicable to bosonic (e.g., Quantum Spin Liquids) or fermionic (e.g., electrons) condensed matter systems. For a pure gauge theory, there is a one form symmetry $I_{[1]}$ associated with the center of the gauge group $G$. We further study the anomalies of the emergent symmetry $I_{[1]}\times G_L$ by higher cobordism invariants as well as QFT analysis. We focus on the simply connected $G=$SU(2) and briefly comment on non-simply connected $G=$SO(3), U(1), other simple Lie groups, and Standard Model gauge groups (SU(3)$\times$SU(2)$\times$U(1))/${\mathbb{Z}}_q$. We comment on SPTs protected by Lorentz symmetry, and the symmetry-extended trivialization for their boundary states.

    ↳ hep-thcond-mat.str-elhep-phmath.ATAnn.Math.Sci.Appl.(2020)·61 citations
26. 26*

    Notes on the Quantum Corrections of Swampland and Trans-Planckian Censorship Conjecture

    Sichun Sun🇮🇹 · Yun-Long Zhang🇯🇵

    We discuss the de Sitter swampland and trans-Planckian censorship conjectures (TCC) from the entropy bound with quantum corrections, namely quantum version of Bousso bound and energy conditions. We include the typical contributions from the entanglement entropy in quasi-de Sitter spacetime. The TCC is not much corrected, whereas the bounds on de Sitter swampland conjecture from energy conditions can be relaxed due to quantum corrections.

    ↳ hep-thgr-qchep-phPLB(2021)·13 citations
27. 27*

    Higher Anomalies, Higher Symmetries, and Cobordisms III: QCD Matter Phases Anew

    Zheyan Wan🇨🇳 · Juven Wang🇺🇸

    We explore QCD${}_4$ quark matter, the $\mu$-T (chemical potential-temperature) phase diagram, possible 't Hooft anomalies, and topological terms, via non-perturbative tools of cobordism theory and higher anomaly matching. We focus on quarks in 3-color and 3-flavor on bi-fundamentals of SU(3), then analyze the continuous and discrete global symmetries and pay careful attention to finite group sectors. We input constraints from $T=CP$ or $CT$ time-reversal symmetries, implementing QCD on unorientable spacetimes and distinct topology. Examined phases include the high T QGP (quark-gluon plasma/liquid), the low T ChSB (chiral symmetry breaking), 2SC (2-color superconductivity) and CFL (3-color-flavor locking superconductivity) at high density. We introduce a possibly useful but only approximate higher anomaly, involving discrete 0-form axial and 1-form mixed chiral-flavor-locked center symmetries, matched by the above four QCD phases. We also enlist as much as possible, but without identifying all of, 't Hooft anomalies and topological terms relevant to Symmetry Protected/Enriched Topological states (SPTs/SETs) of gauged SU(2) or SU(3) QCD${}_d$-like matter theories in general in any spacetime dimensions $d=2,3,4,5$ via cobordism.

    ↳ hep-thcond-mat.supr-conhep-phmath.AT+1NPB(2020)·39 citations
28. 28*

    Reliability of lattice gauge theories

    Jad C. Halimeh🇮🇹 · Philipp Hauke🇮🇹

    Currently, there are intense experimental efforts to realize lattice gauge theories in quantum simulators. Except for specific models, however, practical quantum simulators can never be fine-tuned to perfect local gauge invariance. There is thus a strong need for a rigorous understanding of gauge-invariance violation and how to reliably protect against it. As we show through analytic and numerical evidence, in the presence of a gauge invariance-breaking term the gauge violation accumulates only perturbatively at short times before proliferating only at very long times. This proliferation can be suppressed up to infinite times by energetically penalizing processes that drive the dynamics away from the initial gauge-invariant sector. Our results provide a theoretical basis that highlights a surprising robustness of gauge-theory quantum simulators.

    ↳ cond-mat.quant-gascond-mat.stat-mechhep-lathep-ph+1PRL(2020)·101 citations
29. 29*

    The 2020 Skyrmionics Roadmap

    C. Back · V. Cros · H. Ebert · K. Everschor-Sitte · A. Fert · M. Garst · Tianping Ma · S. Mankovsky · T. L. Monchesky · M. Mostovoy🇳🇱 · N. Nagaosa🇯🇵 · S.S.P. Parkin and 7 other authors

    The notion of non-trivial topological winding in condensed matter systems represents a major area of present-day theoretical and experimental research. Magnetic materials offer a versatile platform that is particularly amenable for the exploration of topological spin solitons in real space such as skyrmions. First identified in non-centrosymmetric bulk materials, the rapidly growing zoology of materials systems hosting skyrmions and related topological spin solitons includes bulk compounds, surfaces, thin films, heterostructures, nano-wires and nano-dots. This underscores an exceptional potential for major breakthroughs ranging from fundamental questions to applications as driven by an interdisciplinary exchange of ideas between areas in magnetism which traditionally have been pursued rather independently. The skyrmionics roadmap provides a review of the present state of the art and the wide range of research directions and strategies currently under way. These are, for instance, motivated by the identification of the fundamental structural properties of skyrmions and related textures, processes of nucleation and annihilation in the presence of non-trivial topological winding, an exceptionally efficient coupling to spin currents generating spin transfer torques at tiny current densities, as well as the capability to purpose-design broad-band spin dynamic and logic devices.

    ↳ cond-mat.str-elcond-mat.mes-hallhep-phnucl-th41 citations
30. 30*

    Inflation without gauge redundancy

    Alfredo Urbano🇮🇹

    In the context of gauge theories, observable quantities, if properly defined and computed, do not depend on the gauge-fixing procedure. In this paper, we develop a formalism that implements this (apparent) tautology in the case of inflation. As a simple application, we discuss Coleman-Weinberg "hilltop" inflation.

    ↳ hep-thhep-phJCAP(2020)·9 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.