HEP Phenomenology·hep-ph

Fri·May 5, 2017Friday·May 5, 2017

27 papers—18 primary·9 cross-listed·reconstructed*

01*
Superparticle phenomenology from the natural mini-landscape
Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Michael Savoy🇺🇸 · Hasan Serce🇺🇸 · Xerxes Tata🇺🇸
The methodology of the heterotic mini-landscape attempts to zero in on phenomenologically viable corners of the string landscape where the effective low energy theory is the Minimal Supersymmetric Standard Model with localized grand unification. The gaugino mass pattern is that of mirage-mediation. The magnitudes of various SM Yukawa couplings point to a picture where scalar soft SUSY breaking terms are related to the geography of fields in the compactified dimensions. Higgs fields and third generation scalars extend to the bulk and occur in split multiplets with TeV scale soft masses. First and second generation scalars, localized at orbifold fixed points or tori with enhanced symmetry, occur in complete GUT multiplets and have much larger masses. This picture can be matched onto the parameter space of generalized mirage mediation. Naturalness considerations, the requirement of the observed electroweak symmetry breaking pattern, and LHC bounds on m(gluino) together limit the gravitino mass to the m_{3/2}~ 5-60 TeV range. The mirage unification scale is bounded from below with the limit depending on the ratio of squark to gravitino masses. We show that while natural SUSY in this realization may escape detection even at the high luminosity LHC, the high energy LHC with \sqrt{s}=33 TeV could unequivocally confirm or exclude this scenario. It should be possible to detect the expected light higgsinos at the ILC if these are kinematically accessible, and possibly also discriminate the expected compression of gaugino masses in the natural mini-landscape picture from the mass pattern expected in models with gaugino mass unification. The thermal WIMP signal should be accessible via direct detection searches at the multi-ton noble liquid detectors such as Xenon-nT or LZ.
hep-phJHEP(2017)·21 citations
02*
Short- and long-baseline sterile neutrino phenomenology
Antonio Palazzo🇮🇹
Several anomalies observed in short-baseline neutrino experiments indicate that the standard 3-flavor framework may be incomplete and point towards the existence of light sterile neutrinos. Here, we present a concise review of the status of the neutrino oscillations within the 3+1 scheme, which is a minimal extension of the standard 3-flavor framework with one sterile neutrino species. We emphasize the potential role of LBL experiments in the searches of CP violation connected to sterile neutrinos and their complementarity with the SBL experiments.
hep-phhep-ex0 citations
03*
Implications of the complex Singlet field for Noncommutative Geometry model
Hosein Karimi Khozani🇱🇧
We consider a complex singlet scalar in the spectral action approach to the standard model. It is shown that there is a range of initial values at the unification scale which is able to produce Higgs and top quark masses at low energies. The stability of the vacuum and the deviation of gauge couplings from experimental values are discussed and compared at the two-loop level with a real scalar singlet and the pure standard model.
hep-phhep-thJHEP(2017)·5 citations
04*
Validity of the Weizsäcker-Williams Approximation and the Analysis of Beam Dump Experiments: Production of an axion, a dark photon, or a new axial-vector boson
Yu-Sheng Liu🇺🇸 · Gerald A. Miller🇺🇸
Beam dump experiments have been used to search for new particles, $ϕ$ , with null results interpreted in terms of limits on masses $m_{ϕ}$ and coupling constants $ϵ$ . However these limits have been obtained by using approximations [including the Weizsäcker-Williams (WW) approximation] or Monte-Carlo simulations. We display methods to obtain the cross section and the resulting particle production rates without using approximations on the phase space integral or Monte-Carlo simulations. In our previous work we examined the case of the new scalar boson production; in this paper we explore all possible new spin-0 and spin-1 particles. We show that the approximations cannot be used to obtain accurate values of cross sections. The corresponding exclusion plots differ by substantial amounts when seen on a linear scale. Furthermore, a new region ( $m_{ϕ} < 2 m_{e}$ ) of parameter space can be explored without using one of the common approximations, $m_{ϕ} ≫ m_{e}$ . We derive new expressions for the three photon decays of dark photon and four photon decays of new axial-vector bosons. As a result, the production cross section and exclusion region of different low mass ( $m_{ϕ} < 2 m_{e}$ ) bosons are very different. Moreover, our method can be used as a consistency check for Monte-Carlo simulations.
hep-phhep-exnucl-exnucl-thPRD(2017)·113 citations
05*
Gravitational waves from a first order electroweak phase transition: a brief review
David J. Weir🇫🇮
We review the production of gravitational waves by an electroweak first order phase transition. The resulting signal is a good candidate for detection at next-generation gravitational wave detectors, such as LISA. Detection of such a source of gravitational waves could yield information about physics beyond the Standard Model that is complementary to that accessible to current and near-future collider experiments. We summarise efforts to simulate and model the phase transition and the resulting production of gravitational waves.
hep-phastro-ph.COPhil.Trans.Roy.Soc.Lond.A(2018)·281 citations
06*
Stringy Origin of Discrete R-symmetries
Hans Peter Nilles🇩🇪
Discrete symmetries play a crucial role in particle physics. They appear abundantly in string model constructions. We focus here on the case of discrete $R$ -symmetries which are intrinsically connected to the Lorentz group in extra dimensions and the appearance of $N$ -extended supersymmetry. In that sense, discrete $R$ -symmetries can be understood as "fractionally" extended supersymmetry. These symmetries reveal insight about the location of fields in extra dimensions (in particular the Higgs boson). Applications can be found in the solution of the $μ$ -problem, suppression of proton decay and the structure of the soft terms of broken supersymmetry.
hep-phhep-thPoS(2017)·19 citations
07*
Flavor Gauge Models Below the Fermi Scale
K.S. Babu🇺🇸 · A. Friedland🇺🇸 · P.A.N. Machado🇺🇸 · I. Mocioiu🇺🇸
The mass and weak interaction eigenstates for the quarks of the third generation are very well aligned, an empirical fact for which the Standard Model offers no explanation. We explore the possibility that this alignment is due to an additional gauge symmetry in the third generation. Specifically, we construct and analyze an explicit, renormalizable model with a gauge boson, $X$ , corresponding to the $B - L$ symmetry of the third family. Having a relatively light (in the MeV to multi-GeV range), flavor-nonuniversal gauge boson results in a variety of constraints from different sources. By systematically analyzing 20 different constraints, we identify the most sensitive probes: kaon, $B^{+}$ , $D^{+}$ and Upsilon decays, $D - D ˉ^{0}$ mixing, atomic parity violation, and neutrino scattering and oscillations. For the new gauge coupling $g_{X}$ in the range $(1 0^{- 2} - 1 0^{- 4})$ the model is shown to be consistent with the data. Possible ways of testing the model in $b$ physics, top and $Z$ decays, direct collider production and neutrino oscillation experiments, where one can observe nonstandard matter effects, are outlined. The choice of leptons to carry the new force is ambiguous, resulting in additional phenomenological implications, such as non-universality in semileptonic bottom decays. The proposed framework provides interesting connections between neutrino oscillations, flavor and collider physics.
hep-phJHEP(2017)·86 citations
08*
To $d$ , or not to $d$ : Recent developments and comparisons of regularization schemes
C. Gnendiger🇨🇭 · A. Signer🇨🇭 · D. Stöckinger🇩🇪 · A. Broggio🇩🇪 · A. L. Cherchiglia🇧🇷 · F. Driencourt-Mangin🇪🇸 · A. R. Fazio🇨🇴 · B. Hiller🇵🇹 · P. Mastrolia🇮🇹 · T. Peraro🇬🇧 · R. Pittau🇪🇸 · G. M. Pruna🇨🇭 and 7 other authors
We give an introduction to several regularization schemes that deal with ultraviolet and infrared singularities appearing in higher-order computations in quantum field theories. Comparing the computation of simple quantities in the various schemes, we point out similarities and differences between them.
hep-phEPJC(2017)·182 citations
09*
Sterile neutrinos in cosmology
Kevork N. Abazajian (UC Irvine)🇺🇸
Sterile neutrinos are natural extensions to the standard model of particle physics in neutrino mass generation mechanisms. If they are relatively light, less than approximately 10 keV, they can alter cosmology significantly, from the early Universe to the matter and radiation energy density today. Here, we review the cosmological role such light sterile neutrinos can play from the early Universe, including production of keV-scale sterile neutrinos as dark matter candidates, and dynamics of light eV-scale sterile neutrinos during the weakly-coupled active neutrino era. We review proposed signatures of light sterile neutrinos in cosmic microwave background and large scale structure data. We also discuss keV-scale sterile neutrino dark matter decay signatures in X-ray observations, including recent candidate $\sim$ 3.5 keV X-ray line detections consistent with the decay of a $\sim$ 7 keV sterile neutrino dark matter particle.
hep-phastro-ph.COastro-ph.HEPhys.Rept.(2017)·273 citations
10*
Non-Unitarity vs sterile neutrinos at DUNE
Josu Hernandez-Garcia🇪🇸 · Jacobo Lopez-Pavon🇨🇭
Neutrino masses are one of the most promising open windows to physics beyond the Standard Model (SM). Several extensions of the SM which accommodate neutrino masses require the addition of right-handed neutrinos to its particle content. These extra fermions will either be kinematically accessible (sterile neutrinos) or not (deviations from Unitarity of the PMNS matrix) but at some point they will impact neutrino oscillation searches. We explore the differences and similitudes between the two cases and compare their present bounds with the expected sensitivities of DUNE. We conclude that Non-Unitarity (NU) effects are too constrained to impact present or near future neutrino oscillation facilities but that sterile neutrinos can play an important role at long baseline experiments.
hep-ph7 citations
11*
The decays $B \to Ψ (2 S) π (K), η_{c} (2 S) π (K)$ in the pQCD approach beyond the leading-order
Zhi-Qing Zhang🇨🇳
Two body $B$ meson decays involving the radially excited meson $ψ (2 S) / η_{c} (2 S)$ in the final states are studied by using the perturbative QCD (pQCD) approach. We find that: (a) The branching ratios for the decays involving $K$ meson are predicted as $B r (B^{+} \to ψ (2 S) K^{+}) = (5.3 7_{- 2.22}^{+ 1.85}) \times 1 0^{- 4}, B r (B^{0} \to ψ (2 S) K^{0}) = (4.9 8_{- 2.06}^{+ 1.71}) \times 1 0^{- 4}, B r (B^{+} \to η_{c} (2 S) K^{+}) = (3.5 4_{- 3.09}^{+ 3.18}) \times 1 0^{- 4}$ , which are consistent well with the present data when including the next-to-leading-order (NLO) effects. Here the NLO effects are from the vertex corrections and the NLO Wilson coefficients. The large errors in the decay $B^{+} \to η_{c} (2 S) K^{+}$ are mainly induced by using the decay constant $f_{η_{c} (2 S)} = 0.24 3_{- 0.111}^{+ 0.079}$ GeV with large uncertainties. (b) While there seems to be some room left for other higher order corrections or the non-perturbative long distance contributions in the decays involving $π$ meson, $B r (B^{+} \to ψ (2 S) π^{+}) = (1.1 7_{- 0.50}^{+ 0.42}) \times 1 0^{- 5}, B r (B^{0} \to ψ (2 S) π^{0}) = 0.5 4_{- 0.23}^{+ 0.20} \times 1 0^{- 5}$ , which are smaller than the present data. The results for other decays can be tested at the running LHCb and forthcoming Super-B experiments. (c) There is no obvious evidence of the direct CP violation being seen in the decays $B \to ψ (2 S) π (K), η_{c} (2 S) π (K)$ in the present experiments, which is supported by our calculations. If a few percent value is confirmed in the future , it would indicate new physics definitely.
hep-phPLB(2017)·5 citations
12*
Quark Seesaw, Dark $U (1)$ symmetry and Baryon-Dark Matter Coincidence
Pei-Hong Gu🇨🇳 · Rabindra N. Mohapatra🇺🇸
We attempt to understand the baryon-dark-matter coincidence problem within the quark seesaw extension of the standard model where parity invariance is used to solve the strong CP problem. The $S U (2)_{L} \times S U (2)_{R} \times U (1)_{B - L}$ gauge symmetry of this model is extended by a dark $U (1)_{X}$ group plus inclusion of a heavy neutral vector-like fermion $χ_{L, R}$ charged under the dark group which plays the role of dark matter. All fermions are Dirac type in this model. Decay of heavy scalars charged under $U (1)_{X}$ leads to simultaneous asymmetry generation of the dark matter and baryons after sphaleron effects are included. The $U (1)_{X}$ group not only helps to stabilize the dark matter but also helps in the elimination of the symmetric part of the dark matter via $χ - χ ˉ$ annihilation. For dark matter mass near the proton mass, it explains why the baryon and dark matter abundances are of similar magnitude (the baryon-dark-matter coincidence problem). This model is testable in low threshold (sub-keV) direct dark matter search experiments.
hep-phPRD(2017)·3 citations
13*
A novel multiquark approach to hadron resonances
S. S. Afonin🇷🇺
A new approach to description of hadron spectroscopy is proposed. By assumption, the form of spectrum is dictated by the trace of energy momentum tensor in QCD. This provides the relativistic and renormalization invariance of hadron masses. The constructed scheme is applied to the light mesons for which two complementary interpretations are worked out. The first one represents an "atomic" structure of resonances above 1 GeV in which the quanta of non-perturbative gluon contributions are quantified via an effective formation of quasiparticles representing likely gluon analogues of positronium. This picture allows to build a "periodic table of the hadronic elements", i.e. to classify hadrons, in some sense, in analogy with Mendeleev table in chemistry. The classification does not require introduction of the orbital angular momentum associated with hadron constituents. The Regge and radial trajectories emerge in a natural way. The second interpretation is based on a "collisional" nature of some (or many) hadrons, specifically of scalar resonances below 1 GeV. Here the role of quasiparticles is played by another hadron. This picture in particular leads to a simple explanation of the puzzling scalar sector below 1 GeV with correct predictions for masses and dominant decay modes.
hep-phhep-latnucl-th1 citation
14*
Little hierarchy in the minimally specified MSSM
Radovan Dermisek🇺🇸 · Navin McGinnis🇺🇸
We study constrained versions of the minimal supersymmetric model and investigate the hierarchy between the electroweak scale and the scale of superpartners that can be achieved without relying on specifying model parameters by more than one digit. This approach automatically avoids scenarios in which a large hierarchy is obtained by special choices of parameters and yet keeps scenarios that would be otherwise disfavored by various sensitivity measures. We consider models with universal gaugino and scalar masses, models with non-universal Higgs masses or non-universal gaugino masses and focus on scenarios in which all the model parameters are either of the same order or zero at the grand unification scale. We find that the maximal hierarchy between the electroweak scale and stop masses, requiring that model parameters are not specified beyond one digit, ranges from a factor of $\sim 10 - 30$ for the CMSSM up to $\sim 300$ for models with non-universal Higgs or gaugino masses.
hep-phInt.J.Mod.Phys.A(2018)·3 citations
15*
Higher-Twist Effects in Light-Cone Sum Rule for the $B \to π$ Form Factor
Aleksey V. Rusov🇩🇪
We calculate the higher-twist corrections to the QCD light-cone sum rule for the $B \to π$ transition form factor. The light-cone expansion of the massive quark propagator in the external gluonic field is extended to include new terms containing the derivatives of gluon-field strength. The resulting analytical expressions for the twist-5 and twist-6 contributions to the correlation function are obtained in a factorized approximation, expressed via the product of the lower-twist pion distribution amplitudes and the quark-condensate density. The numerical analysis reveals that new higher-twist effects for the $B \to π$ form factor are strongly suppressed. This result justifies the conventional truncation of the operator product expansion in the light-cone sum rules up to twist-4 terms.
hep-phEPJC(2017)·25 citations
16*
Constraining Right Handed Gauge Boson Mass from Lepton Number Violating Meson Decays in a Low Scale Left Right Model
Sanjoy Mandal🇮🇳 · Manimala Mitra🇮🇳 · Nita Sinha🇮🇳
We analyze the lepton number violating (LNV) meson decays that arise in a TeV scale Left Right Symmetry model. The right handed Majorana neutrino $N$ along with the right handed or Standard Model gauge bosons mediate the meson decays and provide a resonant enhancement of the rates if the mass of $N$ ( $M_{N}$ ) lies in the range $\sim (100 MeV - 5 GeV)$ . Using the expected upper limits on the number of events for the LNV decay modes $M_{1}^{+} \to ℓ^{+} ℓ^{+} π^{-}$ ~( $M_{1} = B, D, D_{s}, K$ ), we derive constraints plausible on the mass of the right handed charged gauge boson by future searches at the ongoing NA62 and LHCb experiments at CERN, the upcoming Belle II at SuperKEK, as well as at the proposed future experiments, SHiP and FCC-ee. These bounds are complimentary to the limits from same-sign dilepton search at Large Hadron Collider (LHC). The very high intensity of Charmed mesons expected to be produced at SHiP will result in a far more stringent bound, $M_{W_{R}} > 18.4$ ~TeV (corresponding to $M_{N} = 1.46$ ~GeV), than the other existing bounds from collider and neutrinoless double beta decay searches.
hep-phPRD(2017)·29 citations
17*
A full analytic solution of $S O (10)$ -inspired leptogenesis
Pasquale Di Bari🇬🇧 · Michele Re Fiorentin🇬🇧
Recent encouraging experimental results on neutrino mixing parameters prompt further investigation on $S O (10)$ -inspired leptogenesis and on the associated strong thermal solution that has correctly predicted a non-vanishing reactor mixing angle, it further predicts $sin δ ≲ 0$ , now supported by recent results at $\sim 95%$ C.L., normally ordered neutrino masses and atmospheric mixing angle in the first octant, best fit results in latest global analyses. Extending a recent analytical procedure, we account for the mismatch between the Yukawa basis and the weak basis, that in $S O (10)$ -inspired models is described by a CKM-like unitary transformation $V_{L}$ , obtaining a full analytical solution that provides useful insight and reproduces accurately all numerical results, paving the way for future inclusion of different sources of theoretical uncertainties and for a statistical analysis of the constraints. We show how muon-dominated solutions appear for large values of the lightest neutrino mass in the range $(0.01$ -- $1) eV$ but also how they necessarily require a mild fine tuning in the seesaw relation. For the dominant (and untuned) tauon-dominated solutions we show how, turning on $V_{L} ≃ V_{C K M}$ , some of the constraints on the low energy neutrino parameters get significantly relaxed. In particular we show how the upper bound on the atmospheric neutrino mixing angle in the strong thermal solution gets relaxed from $θ_{23} ≲ 4 1^{\circ}$ to $θ_{23} ≲ 4 4^{\circ}$ , an important effect in the light of the most recent NO $ν$ A, T2K and IceCube results.
hep-phJHEP(2017)·23 citations
18*
A Global Bayesian Analysis of Neutrino Mass Data
Allen Caldwell🇩🇪 · Manuel Ettengruber🇩🇪 · Alexander Merle🇩🇪 · Oliver Schulz🇩🇪 · Maximilian Totzauer🇩🇪
We perform a global Bayesian analysis of currently available neutrino data, putting data from oscillation experiments, neutrinoless double beta decay ( $0 ν β β$ ), and precision cosmology on an equal footing. We evaluate the discovery potential of future $0 ν β β$ experiments and the Bayes factor of the two possible neutrino mass ordering schemes for different prior choices. We show that the indication for normal ordering is still very mild and does not strongly depend on realistic prior assumptions or different combinations of cosmological data sets. We find a wide range for $0 ν β β$ discovery potential, depending on the absolute neutrino mass scale, mass ordering and achievable background level.
hep-phastro-ph.COhep-exPRD(2017)·73 citations
19*
Testing different approaches to quantum gravity with cosmology: An overview
Aurélien Barrau🇫🇷
Among the available quantum gravity proposals, string theory, loop quantum gravity, non-commutative geometry, group field theory, causal sets, asymptotic safety, causal dynamical triangulation, emergent gravity are among the best motivated models. As an introductory summary to this special issue of Comptes Rendus Physique, I explain how those different theories can be tested or constrained by cosmological observations.
↳ gr-qcastro-ph.COhep-phhep-thComptes Rendus Physique(2017)·24 citations
20*
Chiral vortical effect in pionic superfluid vs spin alignment of baryons
Oleg V. Teryaev🇷🇺 · Valentin I. Zakharov🇷🇺
We consider chiral fluids, with (nearly) massless fermionic constituents, in the confining phase. Chiral vortical effect (CVE) is the flow of axial current along the axis of rotation of the fluid while the spin alignment is a non-vanishing correlation of polarizations of baryons with the axis of rotation. As the theoretical framework we use the model of pionic superfluidity induced by a non-vanishing isotopic chemical potential. We note that the average value of spin of virtual baryons reproduces the CVE. The role of defects, or vortices is crucial. The model does not apply directly to the quark-gluon plasma but might indicate existence of a mechanism to produce baryons with relatively large polarization in heavy-ion collisions.
↳ hep-thhep-phnucl-th7 citations
21*
Tidal deformations of compact stars with crystalline quark matter
S. Y. Lau🇨🇳 · P. T. Leung🇨🇳 · L.-M. Lin🇨🇳
We study the tidal deformability of bare quark stars and hybrid compact stars composed of a quark matter core in general relativity, assuming that the deconfined quark matter exists in a crystalline color superconducting phase. We find that taking the elastic property of crystalline quark matter into account in the calculation of the tidal deformability can break the universal I-Love relation discovered for fluid compact stars, which connects the moment of inertia and tidal deformability. Our result suggests that measurements of the moment of inertia and tidal deformability can in principle be used to test the existence of solid quark stars, despite our ignorance of the high density equation of state (EOS). Assuming that the moment of inertia can be measured to 10% level, one can then distinguish a 1.4 (1) $M_{⊙}$ solid quark star described by our quark matter EOS model with a gap parameter $Δ = 25$ MeV from a fluid compact star if the tidal deformability can be measured to about 10% (45%) level. On the other hand, we find that the nuclear matter fluid envelope of a hybrid star can screen out the effect of the solid core significantly so that the resulting I-Love relation for hybrid stars still agrees with the universal relation for fluid stars to about 1% level.
↳ astro-ph.HEgr-qchep-phPRD(2017)·40 citations
22*
The hadronic vacuum polarization contribution to the muon $g - 2$ from lattice QCD
M. Della Morte🇩🇰 · A. Francis🇨🇦 · V. Gülpers🇬🇧 · G. Herdoíza🇪🇸 · G. von Hippel🇩🇪 · H. Horch🇩🇪 · B. Jäger🇨🇭 · H.B. Meyer🇩🇪 · A. Nyffeler🇩🇪 · H. Wittig🇩🇪
We present a calculation of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment, $a_{μ}^{h v p}$ , in lattice QCD employing dynamical up and down quarks. We focus on controlling the infrared regime of the vacuum polarization function. To this end we employ several complementary approaches, including Padé fits, time moments and the time-momentum representation. We correct our results for finite-volume effects by combining the Gounaris-Sakurai parameterization of the timelike pion form factor with the Lüscher formalism. On a subset of our ensembles we have derived an upper bound on the magnitude of quark-disconnected diagrams and found that they decrease the estimate for $a_{μ}^{h v p}$ by at most 2%. Our final result is $a_{μ}^{h v p} = (654 \pm 32_{- 23}^{+ 21}) \cdot 1 0^{- 10}$ , where the first error is statistical, and the second denotes the combined systematic uncertainty. Based on our findings we discuss the prospects for determining $a_{μ}^{h v p}$ with sub-percent precision.
↳ hep-lathep-phJHEP(2017)·157 citations
23*
Topology (and axion's properties) from lattice QCD with a dynamical charm
Florian Burger🇩🇪 · Ernst-Michael Ilgenfritz🇷🇺 · Maria Paola Lombardo🇮🇹 · Michael Müller-Preussker🇩🇪 · Anton Trunin🇷🇺
We present results on QCD with four dynamical flavors in the temperature range $0.9 ≲ T / T_{c} ≲ 2$ . We have performed lattice simulations with Wilson fermions at maximal twist and measured the topological charge with gluonic and fermionic methods. The topological charge distribution is studied by means of its cumulants, which encode relevant properties of the QCD axion, a plausible Dark Matter candidate. The topological susceptibility measured with the fermionic method exhibits a power-law decay for $T / T_{c} ≳ 2$ , with an exponent close to the one predicted by the Dilute Instanton Gas Approximation (DIGA). Close to $T_{c}$ the temperature dependent effective exponent approaches the DIGA result from above, in agreement with recent analytic calculations. These results constrain the axion window, once an assumption on the fraction of axions contributing to Dark Matter is made.
↳ hep-lathep-phNPA(2017)·27 citations
24*
Line Operators in the Standard Model
David Tong🇬🇧
There is an ambiguity in the gauge group of the Standard Model. The group is $G = S U (3) \times S U (2) \times U (1) /Γ$ , where $Γ$ is a subgroup of $Z_{6}$ which cannot be determined by current experiments. We describe how the electric, magnetic and dyonic line operators of the theory depend on the choice of $Γ$ . We also explain how the periodicity of the theta angles, associated to each factor of $G$ , differ.
↳ hep-thcond-mat.str-elhep-phJHEP(2017)·126 citations
25*
Is scale-invariance in gauge-Yukawa systems compatible with the graviton?
Nicolai Christiansen🇩🇪 · Astrid Eichhorn🇩🇪 · Aaron Held🇩🇪
We explore whether perturbative interacting fixed points in matter systems can persist under the impact of quantum gravity. We first focus on semi-simple gauge theories and show that the leading order gravity contribution evaluated within the functional Renormalization Group framework preserves the perturbative fixed-point structure in these models discovered in [1]. We highlight that the quantum-gravity contribution alters the scaling dimension of the gauge coupling, such that the system exhibits an effective dimensional reduction. We secondly explore the effect of metric fluctuations on asymptotically safe gauge-Yukawa systems which feature an asymptotically safe fixed point [2]. The same effective dimensional reduction that takes effect in pure gauge theories also impacts gauge-Yukawa systems. There, it appears to lead to a split of the degenerate free fixed point into an interacting infrared attractive fixed point and a partially ultraviolet attractive free fixed point. The quantum-gravity induced infrared fixed point moves towards the asymptotically safe fixed point of the matter system, and annihilates it at a critical value of the gravity coupling. Even after that fixed-point annihilation, graviton effects leave behind new partially interacting fixed points for the matter sector.
↳ hep-thgr-qchep-phPRD(2017)·39 citations
26*
Summary of the recent PHYSTAT- $ν$ Workshops
Louis Lyons🇬🇧
This is a summary of the recent PHYSTAT- $ν$ Workshops in Japan and at Fermilab, on `Statistical Issues in Experimental Neutrino Physics'.
↳ hep-exhep-ph0 citations
27*
Vacuum structure of bifundamental gauge theories at finite topological angles
Yuya Tanizaki🇺🇸 · Yuta Kikuchi🇯🇵
We discuss possible vacuum structures of $S U (n) \times S U (n)$ gauge theories with bifundamental matters at finite $θ$ angles. In order to give a precise constraint, a mixed 't Hooft anomaly is studied in detail by gauging the center $Z_{n}$ one-form symmetry of the bifundamental gauge theory. We propose phase diagrams that are consistent with the constraints, and also give a heuristic explanation of the result based on the dual superconductor scenario of confinement.
↳ hep-thhep-lathep-phJHEP(2017)·89 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.