Flavor gauge models below the Fermi scale

Babu, K. S.; Friedland, Alexander; Machado, Pedro A. N.; Mocioiu, I.

doi:10.1007/jhep12(2017)096

Cited by 79 publications

(120 citation statements)

References 111 publications

(182 reference statements)

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“…Of course, if the set of d = 6 operators is obtained from a NP model at high energies, electroweak gauge invariance generically implies that the NC NSI operators can only be generated together with similar operators involving charged leptons, for which the experimental constraints are much tighter [8,9]. However, recently it has been argued that viable NP models with light mediators (i.e., below the electroweak scale) may lead to large NC NSI effects which would affect neutrino oscillation experiments without spoiling the precise determination of charged lepton observables [10][11][12][13][14][15]. For a recent review on viable NSI models from light mediators see, e.g., Ref.…”

Section: Introductionmentioning

confidence: 99%

Improved global fit to Non-Standard neutrino Interactions using COHERENT energy and timing data

Coloma

Esteban

Gonzalez-Garcia

et al. 2020

J. High Energ. Phys.

111

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We perform a global fit to neutrino oscillation and coherent neutrino-nucleus scattering data, using both timing and energy information from the COHERENT experiment. The results are used to set model-independent bounds on four-fermion effective operators inducing non-standard neutral-current neutrino interactions. We quantify the allowed ranges for their Wilson coefficients, as well as the status of the LMA-D solution, for a wide class of new physics models with arbitrary ratios between the strength of the operators involving up and down quarks. Our results are presented for the COHERENT experiment alone, as well as in combination with the global data from oscillation experiments. We also quantify the dependence of our results for COHERENT with respect to the choice of quenching factor, nuclear form factor, and the treatment of the backgrounds.

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Section: Introductionmentioning

confidence: 99%

Improved global fit to Non-Standard neutrino Interactions using COHERENT energy and timing data

Coloma

Esteban

Gonzalez-Garcia

et al. 2020

J. High Energ. Phys.

111

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“…In gauge invariant models of new physics at high energies, NSI parameters are expected to be subject to tight constraints from charged lepton observables [14,15], leading to no visible effect in oscillations. However, more recently it has been argued that viable gauge models with light mediators (i.e., below the electro-weak scale) may lead to observable effects in oscillations without entering in conflict with other bounds [16][17][18] (see also Ref.[19] for a discussion). In particular, for light mediators, bounds from high-energy neutrino scattering experiments such as CHARM [20] and NuTeV [21] do not apply.…”

mentioning

confidence: 99%

COHERENT enlightenment of the neutrino dark side

et al. 2017

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In the presence of non-standard neutrino interactions (NSI), oscillation data are affected by a degeneracy which allows the solar mixing angle to be in the second octant (aka the dark side) and implies a sign flip of the atmospheric mass-squared difference. This leads to an ambiguity in the determination of the ordering of neutrino masses, one of the main goals of the current and future experimental neutrino program. We show that the recent observation of coherent neutrino-nucleus scattering by the COHERENT experiment, in combination with global oscillation data, excludes the NSI degeneracy at the 3.1σ (3.6σ) CL for NSI with up (down) quarks.The standard three-flavour oscillation scenario is supported by a large amount of data from neutrino oscillation experiments. The determination of oscillation parameters (see, e.g., Ref.[1]) is very robust, and for a broad range of new physics scenarios only small perturbations of the standard oscillation picture are allowed by data. There is, however, an exception to this statement: in the presence of non-standard neutrino interactions (NSI) [2-4] a degeneracy exists in oscillation data, leading to a qualitative change of the lepton mixing pattern. This was first observed in the context of solar neutrinos, where for suitable NSI the data can be explained by a mixing angle θ 12 in the second octant, the so-called LMA-Dark (LMA-D) [5] solution. This is in sharp contrast to the established standard MSW solution [2,6], which requires a mixing angle θ 12 in the first octant.The origin of the LMA-D solution is a degeneracy in oscillation probabilities due to a symmetry of the Hamiltonian describing neutrino evolution in the presence of NSI [7][8][9][10]. This degeneracy involves not only the octant of θ 12 but also a change in sign of the larger neutrino mass-squared difference, ∆m 2 31 , which is used to parameterize the type of neutrino mass ordering (normal versus inverted). Hence, the LMA-D degeneracy makes it impossible to determine the neutrino mass ordering by oscillation experiments [10], and therefore jeopardizes one of the main goals of the upcoming neutrino oscillation program. As discussed in Refs. [5,[10][11][12], non-oscillation data (such as that from neutrino scattering experiments) is needed to break this degeneracy.Recently, coherent neutrino-nucleus scattering has been observed for the first time by the COHERENT experiment [13], using neutrinos produced at the Spallation Neutron Source (SNS) in Oak Ridge National Laboratory. The observed interaction rate is in good agreement with the Standard Model (SM) prediction and can be used to constrain NSI. In this Letter we show that this result excludes the LMA-D solution at 3.1σ (3.6σ) CL for NSI with up (down) quarks when combined with oscillation data.NSI formalism and the LMA-D degeneracy. We consider the presence of neutral-current (NC) NSI in the form of dimension-six four-fermion operators, following the notation of Ref. [8]. Since we are interested in the contribution of the NSI to the effective potential of ne...

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“…Due to the numerous allowed combinations of couplings to standard model (SM) fermions, however, there remain production and decay modes that are yet to be thoroughly explored. Of particular interest, in light of the flavor hierarchy in the SM, is a Z that couples preferentially to the third generation fermions [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

A heavy neutral gauge boson near the Z boson mass pole via third generation fermions at the LHC

Abdullah¹,

Dalchenko²,

Kamon³

et al. 2020

Physics Letters B

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We explore the physics of a new neutral gauge boson, (Z ), coupling to only third-generation particles and with a mass near the electroweak gauge boson mass poles. A Z boson produced by top quarks and decaying to tau leptons is considered. With a simple search strategy inspired by existing analyses of the standard model gauge boson production in association with top quarks, we show that the Large Hadron Collider has good exclusionary power over the model parameter space of the Z boson even at the advent of the high-luminosity era. It is shown that the ttZ process allows one to place limits on right-handed top couplings with a Z boson that preferentially couples to third generation fermions, which are at present very weakly constrained.

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Flavor gauge models below the Fermi scale

Cited by 79 publications

References 111 publications

Improved global fit to Non-Standard neutrino Interactions using COHERENT energy and timing data

Improved global fit to Non-Standard neutrino Interactions using COHERENT energy and timing data

COHERENT enlightenment of the neutrino dark side

A heavy neutral gauge boson near the Z boson mass pole via third generation fermions at the LHC

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