Searching for long-lived light neutralinos from $B$-meson decays with baryonic R-parity violation at Belle II

Fuente: arXiv
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Main Authors: Bertholet, Emilie, Dib, Claudio O., Gandelman, Sara P., Helo, Juan Carlos, Lyubovitskij, Valery E., Nayak, Minakshi, Neill, Nicolás A., Soffer, Abner, Wang, Zeren Simon
Format: Preprint
Published: 2025
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author Bertholet, Emilie
Dib, Claudio O.
Gandelman, Sara P.
Helo, Juan Carlos
Lyubovitskij, Valery E.
Nayak, Minakshi
Neill, Nicolás A.
Soffer, Abner
Wang, Zeren Simon
author_facet Bertholet, Emilie
Dib, Claudio O.
Gandelman, Sara P.
Helo, Juan Carlos
Lyubovitskij, Valery E.
Nayak, Minakshi
Neill, Nicolás A.
Soffer, Abner
Wang, Zeren Simon
contents In a supersymmetry scenario with R-parity violation (RPV), neutralinos with GeV-scale mass, which are necessarily bino-like, are allowed by all constraints and can be produced in association with a baryon in $B$-meson decays via certain $\bar U \bar D \bar D$ operators. In this work, we investigate this scenario with two non-vanishing RPV couplings at the low-energy scale. With one RPV coupling governing the neutralino production rate and another determining its lifetime, this scenario can lead to observable signals with displaced-vertex signatures in the tracking volume of $B$-factories. To maximize the sensitivity to such signals, we develop a new partial-reconstruction technique that yields high efficiency and utilizes most of the decays of relatively heavy, long-lived particles, achieving much better sensitivity than standard full reconstruction. We consider potential background sources and devise selection criteria to suppress their event yields to very low levels. Using a parameterized model of the detector, we estimate in detail the displaced-vertex reconstruction efficiency as a function of neutralino lifetime and mass. For squark masses beyond the LHC limits, we calculate the signal sensitivity of Belle~II, showing that the experiment can probe the RPV couplings well beyond the present bounds, obtained from searches for dinucleon decays, baryon-antibaryon oscillations, and $B^+\to p +\text{missing}$.
format Preprint
id arxiv_https___arxiv_org_abs_2507_00359
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Searching for long-lived light neutralinos from $B$-meson decays with baryonic R-parity violation at Belle II
Bertholet, Emilie
Dib, Claudio O.
Gandelman, Sara P.
Helo, Juan Carlos
Lyubovitskij, Valery E.
Nayak, Minakshi
Neill, Nicolás A.
Soffer, Abner
Wang, Zeren Simon
High Energy Physics - Phenomenology
High Energy Physics - Experiment
In a supersymmetry scenario with R-parity violation (RPV), neutralinos with GeV-scale mass, which are necessarily bino-like, are allowed by all constraints and can be produced in association with a baryon in $B$-meson decays via certain $\bar U \bar D \bar D$ operators. In this work, we investigate this scenario with two non-vanishing RPV couplings at the low-energy scale. With one RPV coupling governing the neutralino production rate and another determining its lifetime, this scenario can lead to observable signals with displaced-vertex signatures in the tracking volume of $B$-factories. To maximize the sensitivity to such signals, we develop a new partial-reconstruction technique that yields high efficiency and utilizes most of the decays of relatively heavy, long-lived particles, achieving much better sensitivity than standard full reconstruction. We consider potential background sources and devise selection criteria to suppress their event yields to very low levels. Using a parameterized model of the detector, we estimate in detail the displaced-vertex reconstruction efficiency as a function of neutralino lifetime and mass. For squark masses beyond the LHC limits, we calculate the signal sensitivity of Belle~II, showing that the experiment can probe the RPV couplings well beyond the present bounds, obtained from searches for dinucleon decays, baryon-antibaryon oscillations, and $B^+\to p +\text{missing}$.
title Searching for long-lived light neutralinos from $B$-meson decays with baryonic R-parity violation at Belle II
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2507.00359