Measuring supersymmetric particle masses at the LHC in scenarios with Baryon-number R-parity violating couplings

The measurement of sparticle masses in the Minimal Supersymmetric Standard Model at the LHC is analysed, in the scenario where the lightest neutralino, the <(<chi>)over tilde>(0)(1), decays into three quarks. Such decays, occurring through the baryon-number violating coupling lambda"(ijk), pose a severe challenge to the capability of the LHC detectors since the final state has no missing energy signature and a high jet multiplicity. We focus on the case lambda"(212) not equal 0 which is the most difficult experimentally. The proposed method is valid over a wide range of SUGRA parameter space with lambda"(212) similar to 10(-5) - 0.1. Simulations are performed of the ATLAS detector at the Large Hadron Collider. Using the <(<chi>)over tilde>(0)(1) from the decay chain (q) over tilde (L) --> <(<chi>)over tilde>(0)(2)q --> (l) over tilde (R)lq --> <(<chi>)over tilde>(0)(1)llq, we show that the <(<chi>)over tilde>(0)(1) and <(<chi>)over tilde>(0)(2) masses can be measured by 3-jet and 3-jet + lepton pair invariant mass combinations. At the SUGRA point m(0) = 100 GeV, m(1/2) = 300 GeV, A(0) = 300 GeV, tan beta = 10, mu >0 and with lambda"(212) = 0.005, we achieve statistical (systematic) errors of 3 (3), 3 (3), 0.3 (4) and 5 (12) GeV, respectively for the masses of the <(<chi>)over tilde>(0)(1), <(<chi>)over tilde>(0)(2), (l) over tilde (R) and (q) over tildeL,with an integrated luminosity of 30 fb(-1).