Report of the GDR working group on the R-parity violation

TL;DR

This comprehensive review analyzes R-parity violation within the MSSM, detailing indirect bounds on RpV couplings, theoretical alternatives that generate hierarchical RpV textures, and collider phenomenology across HERA, LEP, Tevatron, and LHC. It covers bilinear and trilinear RpV effects, single and resonant production channels, and the implications for neutrino masses, including the potential for alignment or small couplings to fit experimental data. The report emphasizes the rich low-energy phenomenology still compatible with strong bounds, while highlighting concrete discovery prospects at current and future colliders and the need for improved theoretical tools and models. It also connects RpV to neutrino physics and cosmology, illustrating how RpV can contribute to neutrino masses and mixing patterns with testable collider signatures.

Abstract

This report summarizes the work of the "R-parity violation group" of the French Research Network (GDR) in Supersymmetry, concerning the physics of supersymmetric models without conservation of R-parity at HERA, LEP, Tevatron and LHC and limits on R-parity violating couplings from various processes. The report includes a discussion of the recent searches at the HERA experiment, prospects for new experiments, a review of the existing limits, and also theoretically motivated alternatives to R-parity and a brief discussion on the implications of R-parity violation on the neutrino masses.

Figures (22)

• Figure 1: The cross sections for the processes $e^+e^- \to {\tilde{\chi} }^{\pm} l^{\mp}$ (a) and $e^+e^- \to {\tilde{\chi} }^0 \nu$ (b), as a function of $\mu$, using the set of parameters: $M_2=200GeV$, $m_0=150GeV$, $\lambda _{m11}=0.05$ and $\tan \beta =2$. The different center of mass energies are indicated under the figures.
• Figure 2:
• Figure 3: Lowest order $s$-channel diagrams for first generation squark production at HERA followed by (a),(c) $\not \space R_p$ decays and (b),(d) gauge decays. In (b) and (d), the emerging neutralino or chargino might subsequently undergo $\not \space R_p$ decays of which examples are shown in the doted boxes for (b) the $\chi_1^{+}$ and (d) the $\chi_1^0$.
• Figure 4: (a) Exclusion upper limits at $95 \%$ C.L. for the coupling $\lambda'_{1j1}$ as a function of the squark mass for a specific set of MSSM parameters ($M_{\chi^0_1} = 40 \hbox{$\;\hbox{\rm GeV}$}$, $\chi^0_1 \sim \tilde{gamma}$, see text). Gauge and $\hbox{$\not \space R_p$}$ decays of the squarks have been combined. Regions above the curves are excluded; (b) The relative contributions of channels S1, S3 and S4 versus the squark mass; (c) and (d) : as (a) and (b) but for a $40 \hbox{$\;\hbox{\rm GeV}$}$$\chi^0_1$ dominated by its zino component.
• Figure 5: Exclusion upper limits at $95 \%$ C.L. for the coupling $\lambda'_{1j1}$ as a function of squark mass, for various masses of a $\tilde{\gamma}$-like $\chi^0_1$; the difference obtained between a $40 \hbox{$\;\hbox{\rm GeV}$}$$\tilde{\gamma}$-like and $\tilde{Z}$-like $\chi^0_1$ is also shown; also represented are the most stringent indirect limits on $\lambda'_{111}$ and $\lambda'_{1j1}$, $j=2,3$.