A
bstract
We investigate the potential to probe new neutrino physics with future experiments measuring coherent neutrino-nucleus scattering. Experiments with high statistics should become feasible ...soon and allow to constrain parameters with unprecedented precision. Using a benchmark setup for a future experiment probing reactor neutrinos, we study the sensitivity on neutrino non-standard interactions and new exotic neutral currents (scalar, tensor, etc). Compared to Fermi interaction, percent and permille level strengths of the new interactions can be probed, superseding for some observables the limits from future neutrino oscillation experiments by up to two orders of magnitude.
A
bstract
Right-handed neutrinos (
ν
R
) are often considered as a portal to new hidden physics. It is tempting to consider a gauge singlet scalar (
ϕ
) that exclusively couples to
ν
R
via a
ν
R
ν
Rϕ
...term. Such a
ν
R
-philic scalar does not interact with charged fermions at tree level but loop-induced effective interactions are inevitable, which are systematically investigated in this work. The magnitude of the loop-induced couplings coincidentally meets the current sensitivity of fifth-force searches. In particular, the loop-induced coupling to muons could be tested in the recent LIGO observations of neutron star mergers as there might be a sizable Yukawa force in the binary system mediated by the
ν
R
-philic scalar.
A
bstract
We consider the light
Z′
explanation of the muon
g −
2 anomaly. Even if such a
Z′
has no tree-level coupling to electrons, in general one will be induced at loop-level. We show that future ...beam dump experiments are powerful enough to place stringent constraints on—or discover—a
Z
′ with loop-suppressed couplings to electrons. Such bounds are avoided only if the
Z
′ has a large interaction with neutrinos, in which case the scenario will be bounded by ongoing neutrino scattering experiments. The complementarity between beam dump and neutrino scattering experiments therefore indicates that there are good prospects of probing a large part of the
Z
′ parameter space in the near future.
A
bstract
We perform a systematic study of the electric and magnetic dipole moments of dark matter (DM) that are induced at the one-loop level when DM experiences four-fermion interactions with ...Standard Model (SM) charged fermions. Related to their loop nature these moments can largely depend on the UV completion at the origin of the four-fermion operators. We illustrate this property by considering explicitly two simple ways to generate these operators, from
t
- or
s
-channel tree-level exchange. Fixing the strength of these interactions from the DM relic density constraint, we obtain in particular a magnetic moment that, depending on the interaction considered, lies typically between 10
−
20
to 10
−
23
ecm or identically vanishes. These non-vanishing values induce, via photon exchange, DM-nucleus scattering cross sections that could be probed by current or near future direct detection experiments.
A
bstract
We consider a generic dark photon that arises from a hidden U(1) gauge symmetry imposed on right-handed neutrinos (
ν
R
). Such a
ν
R
-philic dark photon is naturally dark due to the ...absence of tree-level couplings to normal matter. However, loop-induced couplings to charged leptons and quarks are inevitable, provided that
ν
R
mix with left-handed neutrinos via Dirac mass terms. We investigate the loop-induced couplings and find that the
ν
R
-philic dark photon is not inaccessibly dark, which could be of potential importance to future dark photon searches at SHiP, FASER, Belle-II, LHC 14 TeV, etc.
A
bstract
Large neutrino event numbers in future experiments measuring coherent elastic neutrino nucleus scattering allow precision measurements of standard and new physics. We analyze the current ...and prospective limits of a light scalar particle coupling to neutrinos and quarks, using COHERENT and CONUS as examples. Both lepton number conserving and violating interactions are considered. It is shown that current (future) experiments can probe for scalar masses of a few MeV couplings down to the level of 10
−4
(10
−6
). Scalars with masses around the neutrino energy allow to determine their mass via a characteristic spectrum shape distortion. Our present and future limits are compared with constraints from supernova evolution, Big Bang nucleosynthesis and neutrinoless double beta decay. We also outline UV-complete underlying models that include a light scalar with coupling to quarks for both lepton number violating and conserving coupling to neutrinos.
A
bstract
We consider the production of a new MeV-scale fermion in coherent elastic neutrino-nucleus scattering. The effect on the measurable nucleon recoil spectrum is calculated. Assuming that the ...new fermion couples to neutrinos and quarks via a singlet scalar, we set limits on its mass and coupling using COHERENT data and also determine the sensitivity of the CONUS experiment. We investigate the possible connection of the new fermion to neutrino mass generation. The possibility of the new fermion being the dark matter particle is also studied.
A
bstract
New physics can emerge at low energy scales, involving very light and very weakly interacting new particles. These particles can mediate interactions between neutrinos and usual matter and ...contribute to the Wolfenstein potential relevant for neutrino oscillations. We compute the Wolfenstein potential in the presence of ultra-light scalar and vector mediators and study the dependence of the potential on the mediator mass
m
A
, taking the finite size of matter distribution (Earth, Sun, supernovae) into consideration. For ultra-light mediators with
m
A
−
1
comparable to the size of the medium (
R
), the usual
m
A
−
2
dependence of the potential is modified. In particular, when
m
A
−
1
≫
R
, the potential does not depend on
m
A
. Taking into account existing bounds on light mediators, we find that for the scalar case significant effects on neutrino propagation are not possible, while for the vector case large matter effects are allowed for
m
A
∈ 2
×
10
−
17
, 4
×
10
−
14
eV and the gauge coupling
g ∼
10
−
25
.
Recently more generalized four-fermion interactions of neutrinos such as tensor and scalar interactions (TSIs) have been extensively studied in response to forthcoming precision measurements of ...neutrino interactions. We show that due to the chirality-flipping nature, at the one-loop level TSIs typically generate much larger (107–1010) neutrino magnetic moments (νMMs) than the vector case. For some cases, the large νMMs generated by TSIs may reach the known bounds, which implies potentially important interplay between probing TSIs and searching for νMMs in current and future neutrino experiments.
A
bstract
The MUonE experiment aims at a precision measurement of the hadronic vacuum polarization contribution to the muon
g −
2, via elastic muon-electron scattering. Since the current muon
g −
2 ...anomaly hints at the potential existence of new physics (NP) related to the muon, the question then arises as to whether the measurement of hadronic vacuum polarization in MUonE could be affected by the same NP as well. In this work, we address this question by investigating a variety of NP explanations of the muon
g −
2 anomaly via either vector or scalar mediators with either flavor-universal, non-universal or even flavor-violating couplings to electrons and muons. We derive the corresponding MUonE sensitivity in each case and find that the measurement of hadronic vacuum polarization at the MUonE is not vulnerable to any of these NP scenarios.
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