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Dev, P.S. Bhupal

Publications and source records attributed to Dev, P.S. Bhupal.

Probing the muon ( g − 2) anomaly at the LHC in final states with two muons and two taus

The longstanding muon (g - 2) anomaly, as well as some hints of lepton flavor universality violation in B-meson decays, could be signaling new physics beyond the Standard Model (SM). A minimal R-parity-violating supersymmetric framework with light third-generation sfermions (dubbed as ‘RPV3’) provides a compelling solution to these flavor anomalies, while simultaneously addressing other pressing issues of the SM. We propose a new RPV3 scenario for the solution of the muon (g - 2) anomaly, which leads to an interesting LHC signal of $µ$ + $µ$ - $τ$ + $τ$ - final state. We analyze the Run-2 LHC multilepton data to derive stringent constraints on the sneutrino mass and the relevant RPV coupling in this scenario. We then propose dedicated selection strategies to improve the bound even with the existing dataset. We also show that the high-luminosity LHC will completely cover the remaining muon (g - 2)-preferred parameter space, thus providing a robust, independent test of the muon (g - 2) anomaly.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Neutrino self-interactions: A white paper

Neutrinos are the Standard Model (SM) particles which we understand the least, often due to how weakly they interact with the other SM particles. Beyond this, very little is known about interactions among the neutrinos, i.e., their self-interactions. The SM predicts neutrino self-interactions at a level beyond any current experimental capabilities, leaving open the possibility for beyond-the-SM interactions across many energy scales. In this white paper, we review the current knowledge of neutrino self-interactions from a vast array of probes, from cosmology, to astrophysics, to the laboratory. Furthermore, we also discuss theoretical motivations for such self-interactions, including neutrino masses and possible connections to dark matter. Looking forward, we discuss the capabilities of searches in the next generation and beyond, highlighting the possibility of future discovery of this beyond-the-SM physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

The Forward Physics Facility at the High-Luminosity LHC

High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF’s physics potential.

47 OTHER INSTRUMENTATION↗

A new probe of relic neutrino clustering using cosmogenic neutrinos

We propose a new probe of cosmic relic neutrinos (CνB) using their resonant scattering against cosmogenic neutrinos. Depending on the lightest neutrino mass and the energy spectrum of the cosmogenic neutrino flux, a Standard Model vector meson (such as a hadronic ρ) resonance can be produced via $v\bar{v}$ annihilation. This leads to a distinct absorption feature in the cosmogenic neutrino flux at an energy solely determined by the meson mass and the neutrino mass, apart from redshift. By numerical coincidence, the position of the ρ-resonance overlaps with the originally predicted peak of the Greisen-Zatsepin-Kuzmin (GZK) neutrino flux, which offers an enhanced effect at higher redshifts. We show that this absorption feature in the GZK neutrino flux may be observable in future radio-based neutrino observatories, such as IceCube-Gen2 radio, provided there exists a large overdensity in the CνB distribution. This therefore provides a new probe of CνB clustering at large redshifts, complementary to the laboratory probes (such as KATRIN) at zero redshift.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Impact of improved energy resolution on DUNE sensitivity to neutrino non-standard interactions

The full physics potential of the next-generation Deep Underground Neutrino Experiment (DUNE) is still being explored. In particular, there have been some recent studies on the possibility of improving DUNE’s neutrino energy reconstruction. The main motivation is that a better determination of the neutrino energy in an event-by-event basis will translate into an improved measurement of the Dirac C P phase and other neutrino oscillation parameters. To further motivate studies and improvements on the neutrino energy reconstruction, we evaluate the impact of energy resolution at DUNE on an illustrative new physics scenario, viz. non-standard interactions (NSI) of neutrinos with matter. We show that a better energy resolution in comparison to the ones given in the DUNE conceptual and technical design reports may significantly enhance the experimental sensitivity to NSI, particularly when degeneracies are present. While a better reconstruction of the first oscillation peak helps disentangling standard C P effects from those coming from NSIs, we find that the second oscillation peak also plays a nontrivial role in improving DUNE’s sensitivity.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Light, long-lived B - L gauge and Higgs bosons at the DUNE near detector

The low-energy U(1)B-L gauge symmetry is well-motivated as part of beyond Standard Model physics related to neutrino mass generation. We show that a light B - L gauge boson Z' and the associated U(1) B-L -breaking scalar φ can both be effectively searched for at high-intensity facilities such as the near detector complex of the Deep Underground Neutrino Experiment (DUNE). Without the scalar φ, the Z' can be probed at DUNE up to mass of 1 GeV, with the corresponding gauge coupling g BL as low as 10 -9 . In the presence of the scalar φ with gauge coupling to Z', the DUNE capability of discovering the gauge boson Z' can be significantly improved, even by one order of magnitude in g BL , due to additional production from the decay φ → Z'Z'. The DUNE sensitivity is largely complementary to other long-lived Z' searches at beam-dump facilities such as FASER and SHiP, as well as astrophysical and cosmological probes. On the other hand, the prospects of detecting φ itself at DUNE are to some extent weakened in presence of Z', compared to the case without the gauge interaction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Leptonic scalars at the LHC

We explore the collider prospects of neutrino non-standard interaction with a Standard Model (SM) gauge-singlet leptonic scalar ϕ carrying two units of lepton-number-charge. These leptonic scalars are forbidden from interacting with the SM fermions at the renormalizable level and, if one allows for higher-dimensional operators, couple predominantly to SM neutrinos. For masses at or below the electroweak scale, ϕ decays exclusively into neutrinos. Its characteristic production signature at hadron collider experiments like the LHC would be via the vector boson fusion process and leads to same-sign dileptons, two forward jets in opposite hemispheres, and missing transverse energy, i.e., $$ pp\to {\mathrm{\ell}}_{\alpha}^{\pm }{\mathrm{\ell}}_{\beta}^{\pm } jj+{E}_T^{\mathrm{miss}}\left(\alpha, \beta =e,\mu, \tau \right) $$ pp → ℓ α ± ℓ β ± jj + E T miss α β = e μ τ . Exploiting the final states of electrons and muons, we estimate, for the first time, the sensitivity of the LHC to these lepton-number-charged scalars. We show that the LHC sensitivity is largely complementary to that of low-energy precision measurements of the decays of charged leptons, charged mesons, W , Z and the SM Higgs boson, as well as the neutrino beam experiments like MINOS, and searches for neutrino self-interactions at IceCube and in cosmological observations. For ϕ mass larger than roughly 10 GeV, our projected LHC sensitivity would surpass all existing bounds.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗