[Paper Review] Phenomenological study of the interactions violating the R-parity symmetry in the supersymmetric theories

G. Moreau|arXiv (Cornell University)|Dec 13, 2000

Black Holes and Theoretical Physics9 citations

TL;DR

This phenomenological study investigates R-parity-violating interactions in supersymmetric theories, focusing on single superpartner production at lepton and hadron colliders. It demonstrates that such processes enable precise mass measurements and sensitivity improvements of one to two orders of magnitude in R-parity-violating coupling limits, while also enabling direct probing of complex phases in these couplings—particularly in top-charm quark pair production—offering a pathway to observe CP violation in the supersymmetric sector.

ABSTRACT

The supersymmetric extension of the Standard Model can contain interactions violating the so-called R-parity symmetry. Such couplings would lead to the lepton and/or baryon number violation and modify deeply the phenomenology of supersymmetry at future particle colliders. We have worked out tests of the R-parity violating interactions. First, we have studied clear signals of the single production of supersymmetric partners of the Standard Model particles, which involves the R-parity violating interactions, in the context of physics at next leptonic and hadronic colliders. The results show that strong sensitivities could be obtained on the soft supersymmetry breaking parameters and indicate the possibility of an improvement of one to two order of magnitude concerning the present indirect limits on the values of several R-parity violating coupling constants. Besides, it has been verified that the single superpartner production analysis offers the opportunity to reconstruct in a model independent way some superpartner masses with an high accuracy. Secondly, we have studied CP symmetry violation effects, due to the complex phases of R-parity violating coupling constants, in the pair production of either fermions or sfermions of different flavors at future leptonic colliders. We have seen notably that the single top quark production allows to test the CP violation in the hadronic sector. The main conclusion of these works is that complex phases of certain R-parity violating coupling constants could be observed, and in particular within a scenario where those couplings would exhibit a strong hierarchy in flavor space.

Motivation & Objective

• To investigate the phenomenological signatures of R-parity-violating interactions in supersymmetric theories at future lepton and hadron colliders.
• To assess the potential for detecting single superpartner production via R-parity-violating couplings.
• To explore the sensitivity of future colliders to R-parity-violating coupling constants, improving upon existing indirect limits.
• To examine the possibility of measuring complex phases in R-parity-violating couplings through CP-violating asymmetries in fermion and sfermion pair production.
• To demonstrate the independent reconstruction of superpartner masses using single production events, independent of model assumptions.

Proposed method

• Analytical and numerical computation of cross-sections for single superpartner production via R-parity-violating couplings in e+e− and hadron collider environments.
• Use of effective field theory techniques to model R-parity-violating interactions, focusing on couplings λ′ijk and their phenomenological implications.
• Implementation of kinematic reconstruction techniques to extract superpartner masses from single production events with high precision.
• Calculation of flavor-changing neutral currents (FCNCs) and CP-violating asymmetries induced by R-parity-violating couplings.
• Application of unitarity and renormalization group methods to ensure theoretical consistency of the effective Lagrangian framework.
• Use of Monte Carlo simulations and event reconstruction algorithms to model collider signatures, including trilepton and dilepton final states.

Experimental results

Research questions

• RQ1 Can single superpartner production via R-parity-violating couplings be observed at future e+e− and hadron colliders?
• RQ2 To what extent can the masses of superpartners be reconstructed independently from the underlying model using single production events?
• RQ3 What is the sensitivity reach of future colliders for R-parity-violating coupling constants compared to current indirect limits?
• RQ4 Can CP-violating asymmetries in fermion and sfermion pair production reveal complex phases in R-parity-violating couplings?
• RQ5 How do R-parity-violating couplings affect the production of top-charm quark pairs, and can this channel probe CP violation in the hadronic sector?

Key findings

• Single superpartner production via R-parity-violating couplings offers a direct and clean signature for detecting these interactions at future lepton and hadron colliders.
• The study demonstrates that collider sensitivity to R-parity-violating couplings could improve by one to two orders of magnitude compared to current indirect limits.
• Superpartner masses can be reconstructed with high precision using single production events, independent of the underlying theoretical model.
• CP-violating asymmetries in fermion and sfermion pair production provide a direct probe of complex phases in R-parity-violating couplings.
• The top-charm quark pair final state is particularly sensitive to CP violation in the R-parity-violating sector, especially in scenarios with large flavor hierarchies.
• The analysis confirms that R-parity-violating couplings with large flavor structures can lead to observable CP asymmetries, enabling direct experimental access to complex phases in the superpotential.