Constraints on the U(1)L gauge boson in a wide mass range

104

166

One proposed component of the upcoming Deep Underground Neutrino Experiment (DUNE) near detector complex is a multi-purpose, magnetized, gaseous argon time projection chamber: the Multi-Purpose Detector (MPD). We explore the new-physics potential of the MPD, focusing on scenarios in which the MPD is significantly more sensitive to new physics than a liquid argon detector, specifically searches for semi-long-lived particles that are produced in/near the beam target and decay in the MPD. The specific physics possibilities studied are searches for dark vector bosons mixing kinetically with the Standard Model hypercharge group, leptophilic vector bosons, dark scalars mixing with the Standard Model Higgs boson, and heavy neutral leptons that mix with the Standard Model neutrinos. We demonstrate that the MPD can extend existing bounds in most of these scenarios. We illustrate how the ability of the MPD to measure the momentum and charge of the final state particles leads to these bounds. arXiv:1912.07622v1 [hep-ph] 16 Dec 2019 Liquid Argon Near Detector: The liquid argon near detector has a width (transverse to the beam direction) of 7 m, a height of 3 m, and a length (in the beam direction) of 5 m. The fiducial mass of the near detector is 50 t of argon. See Ref. [2] for more detail.Multi-Purpose Detector: The Multi-Purpose Detector (MPD) is a magnetic spectrometer with a cylindrical high-pressure gaseous argon time projection chamber (HPTPC) at its heart. The HPTPC has a diameter of 5 m and a length of 5 m. It is surrounded by an electromagnetic calorimeter (ECAL) and the HPTPC+ECAL system is situated inside a magnet with 0.5 T central field. The axis of the cylinder is perpendicular to the beam direction. However, for simplicity, when simulating our signals (see Section 3), * Some projections of DUNE operation include the possibility of an upgraded beam (roughly twice the number of protons on target per year) that can operate in the second half of the experiment. We assume a constant number of protons on target per year, so our ten-year projection is equivalent to a shorter operation time with such an upgraded beam. † This is in contrast with the LArTPC, where the conversion distance of photons is O(10 cm). Far more photons can fake the signal of e + e − in the LArTPC than in the HPTPC. * Ref. [63] provides a thorough review of searches for dark photons and existing constraints. * The results of this analysis in antineutrino mode are qualitatively equivalent.

Section: Section 5: Leptophilic Gauge Bosonsmentioning

confidence: 99%

Searches for decays of new particles in the DUNE Multi-Purpose near Detector

Berryman

Gouvêa

Fox

et al. 2020

104

166

“…9 This result corrects the conclusion of [14], where a simplified estimate suggested that the measured π 0 branching ratio was inconsistent with measurements of η → µ + µ − for the same A mass and axial couplings. 10 The neutrino-electron bounds here are translated from [31] by assuming c e A ∼ c e V , c νµ ∼ κc νe , which is true for a generic point in the 2HDM parameter space and suffices to illustrate the dominance of neutrino bounds for large κ. Figure 4.…”

Section: Surveying the Parameter Spacementioning

confidence: 99%

Light weakly coupled axial forces: models, constraints, and projections

Kahn

Krnjaic

Mishra-Sharma

et al. 2017

103

Abstract:We investigate the landscape of constraints on MeV-GeV scale, hidden U(1) forces with nonzero axial-vector couplings to Standard Model fermions. While the purely vector-coupled dark photon, which may arise from kinetic mixing, is a well-motivated scenario, several MeV-scale anomalies motivate a theory with axial couplings which can be UV-completed consistent with Standard Model gauge invariance. Moreover, existing constraints on dark photons depend on products of various combinations of axial and vector couplings, making it difficult to isolate the effects of axial couplings for particular flavors of SM fermions. We present a representative renormalizable, UV-complete model of a dark photon with adjustable axial and vector couplings, discuss its general features, and show how some UV constraints may be relaxed in a model with nonrenormalizable Yukawa couplings at the expense of fine-tuning. We survey the existing parameter space and the projected reach of planned experiments, briefly commenting on the relevance of the allowed parameter space to low-energy anomalies in π 0 and 8 Be * decay.

“…LEP experiments. The high mass regions are sensitive to the LEP experiments which give the exclusion limit depicted by the brown region [56]. The constraint for the contact interactions [57] is valid only for the M Z much larger than the collision energy at LEP, 209 GeV, while the initial state photon radiation process, e + e − → γνν [58], can be used for the M Z lower than the collision energy.…”

Section: Jhep02(2017)031mentioning

confidence: 99%

Right-handed neutrino dark matter under the B − L gauge interaction

Kaneta

Kang

Lee

2017

Self Cite

Abstract:We study the right-handed neutrino (RHN) dark matter candidate in the minimal U(1) B−L gauge extension of the standard model. The U(1) B−L gauge symmetry offers three RHNs which can address the origin of the neutrino mass, the relic dark matter, and the matter-antimatter asymmetry of the universe. The lightest among the three is taken as the dark matter candidate, which is under the B − L gauge interaction. We investigate various scenarios for this dark matter candidate with the correct relic density by means of the freeze-out or freeze-in mechanism. A viable RHN dark matter mass lies in a wide range including keV to TeV scale. We emphasize the sub-electroweak scale light B − L gauge boson case, and identify the parameter region motivated from the dark matter physics, which can be tested with the planned experiments including the CERN SHiP experiment.