A
bstract
We formulate an Effective Field Theory (EFT) for Non Standard neutrino Interactions (NSI) in elastic scattering with light quarks, leptons, gluons and photons, including all possible ...operators of dimension 5, 6 and 7. We provide the expressions for the cross sections in coherent neutrino-nucleus scattering and in deep inelastic scattering. Assuming single operator dominance we constrain the respective Wilson coefficient using the measurements by the COHERENT and CHARM collaborations. We also point out the constraining power of future elastic neutrino-nucleus scattering experiments. Finally, we explore the implications of the bounds for SMEFT operators above the electroweak breaking scale.
A
bstract
We introduce two anomaly free versions of Froggatt-Nielsen (FN) models, based on either
G
FN
= U(1)
3
or
G
FN
= U(1) horizontal symmetries, that generate the SM quark and lepton flavor ...structures. The structure of these “inverted” FN models is motivated by the clockwork mechanism: the chiral fields, singlets under
G
FN
, are supplemented by chains of vector-like fermions charged under
G
FN
. Unlike the traditional FN models the hierarchy of quark and lepton masses is obtained as an expansion in
M
/〈
ϕ
〉, where
M
is the typical vector-like fermion mass, and 〈
ϕ
〉 the flavon vacuum expectation value. The models can be searched for through deviations in flavor observables such as
K
−
K
¯
mixing,
μ → e
conversion, etc., where the present bounds restrict the masses of vector-like fermions to be above
O
(10
7
GeV). If
G
FN
is gauged, the models can also be probed by searching for the flavorful
Z′
gauge bosons. In principle, the
Z′
s can be very light, and can be searched for using precision flavor, astrophysics, and beam dump experiments.
A
bstract
We present the full basis of effective operators relevant for dark matter direct detection, up to and including operators of mass dimension seven. We treat the cases where dark matter is ...either a Dirac fermion, a Majorana fermion, a complex scalar, or a real scalar, allowing for dark matter to furnish a general representation of the electroweak gauge group. We describe the algorithmic procedure used to obtain the minimal set of effective operators and provide the tree-level matching conditions onto the effective theory valid below the electroweak scale.
A
bstract
We explore CP-violating (CPV) effects of heavy New Physics in flavour-changing quark dipole transitions, within the framework of Standard Model Effective Field Theory (SMEFT). First, we ...establish the relevant dimension six operators and consider the Renormalisation Group (RG) evolution of the appropriate Wilson coefficients. We investigate RG-induced correlations between different flavour-violating processes and electric dipole moments (EDMs) within the Minimal Flavour Violating and U(2)
3
quark flavour models. At low energies, we set bounds on the Wilson coefficients of the dipole operators using CPV induced contributions to observables in non-leptonic and radiative
B
,
D
and
K
decays as well as the neutron and electron EDMs. This enables us to connect observable CPV effects at low energies and general NP appearing at high scales. We present bounds on the Wilson coefficients of the relevant SMEFT operators at the high scale Λ = 5 TeV, and discuss most sensitive CPV observables for future experimental searches.
Light Dark Matter from Entropy Dilution Evans, Jared A.; Ghalsasi, Akshay; Gori, Stefania ...
The journal of high energy physics,
02/2020, Letnik:
2020, Številka:
2
Journal Article
Recenzirano
Odprti dostop
A
bstract
We show that a thermal relic which decouples from the standard model (SM) plasma while relativistic can be a viable dark matter (DM) candidate, if the decoupling is followed by a period of ...entropy dilution that heats up the SM, but not the dark sector. Such diluted hot relics can be as light as few keV, while accounting for the entirety of the DM, and not conflicting with cosmological and astrophysical measurements. The requisite dilution can be achieved via decays of a heavy state that dominates the energy budget of the universe in the early matter dominated era. The heavy state decays into the SM particles, heats up the SM plasma, and dilutes the hidden sector. The interaction required to equilibrate the two sectors in the early universe places a bound on the maximum possible dilution as a function of the decoupling temperature. As an example of diluted hot relic DM we consider a light Dirac fermion with a heavy dark photon mediator. We present constraints on the model from terrestrial experiments (current and future), astrophysics, and cosmology.
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