Genuine SUSY signatures fromug→d˜χ˜i+andug→

Abstract

March 2008 (corrected version)PTA/08-009 arXiv:0803.0813 [hep-ph] Genuine SUSY signatures from ug →dχ AbstractWe analyze the quark-gluon induced process ug →dχ + i , including the one loop electroweak (EW) effects in the minimal supersymmetric model (MSSM). This process is dominated byd L -production and is determined by four helicity amplitudes, three of which are violating helicity conservation, and another one which respects it and is logarithmically enhanced at high energy. Combining this ug →d Lχ + i analysis with a corresponding one for ug → dW + , we obtain simple approximate relations between the two processes, testing the MSSM structure at the amplitude and the cross section levels. These relations become exact at asymptotic energies and, provided the SUSY scale is not too heavy, they may be approximately correct at LHC energies also. In addition to these, we study the 1loop EW corrections to the inclusivedχ + i production at LHC, presenting as examples, the p T and angular distributions. Comparing these to the corresponding predictions for W +jet production derived earlier, provides an accurate test of the supersymmetric assignments. IntroductionIn a previous paper we have shown that the 1loop virtual SUSY EW effects in the process ug → dW + , present a number of remarkable properties [1]. Among them, is the role of SUSY in ensuring the validity of Helicity Conservation (HC) for any two-body process at high energy, to all orders in perturbation theory [2]. By this we mean the fact that at very high energies and fixed angles, the only surviving two-body amplitudes are those where the sum of the initial particle helicities equal to the sum of the final particle helicities [2]. According to HC, these are the only amplitudes that could possibly contribute at asymptotic energies, and in fact receive the logarithmic enhancements extensively studied in [3] and [4]. All the rest must vanish in this limit.These results raised several questions concerning the deeper reasons for the validity of HC, and whether terms involving ratios of masses could possibly violate it 1 . Such questions called for further studies of various explicit processes [1]. Particular among them, are processes involving heavy SUSY-particles in the final state, where establishing of HC is expected to be delayed.Along these lines of thought, we present here an analysis of the process ug →d Lχ + i , which starts from the same initial state as ug → dW + , but its final state involves SUSY partners of dW + . Such a study could provide insights into the SUSY implications, which of course become clearest at the highest energy.Denoting the helicities and momenta of the incoming and outgoing particles in the above process aswe write the corresponding helicity amplitudes as Fχ λuλgλχ . At Born level, these amplitudes are determined by the two diagrams in Fig.1a, characterized by a u-quark exchange in the s-channel, and ad L -squark exchange in the u-channel. Because of the negligible u and d quark masses, the charginos couple only through their...

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“…Previous semianalytical results for these have appeared in [23]; but there, the numerical components were blurring the picture and the supersimplicity structure was not visible.…”

“…In order to get the SM high energy amplitudes, we have to work with the complete 1-loop results of [12], suppressing the SUSY exchange diagrams. Ignoring also the small high energy HV amplitudes, and using for the HC ones the same definitions (18), (23), we get (29) expressed completely in terms of the forms (5), (13), (16) and linear logarithms (ln r ts , ln r tu ).…”

“…We repeat that (18), (23), (30), (31) are valid in both, SM and MSSM, provided of course, that the appropriate C −∓−∓ and δC residual are used.…”

High Scale Physics Connection to LHC Data

“…We discuss some prominent signatures below. (Some recent analyses of signatures can be found in [45,46,47,48,49,50,51,52,53,54,55,56,57,58]). The first of these is the excess of trileptonic events [59] at colliders.…”

Recent Developments in Supersymmetric and Hidden Sector Dark Matter

“…Since it is imperative that one sample all the patterns, benchmarks for the 22 patterns have been given recently in [2]. As an example, an application using mSP4 is given in [39]. With the inclusion of nonuniversalities in the soft breaking sector for the cases of NUH, NUq3, and NUG 15 more mass patterns emerge which may be labeled as NUSP1-NUSP15 (see [2]).…”