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In the R-parity violating SUSY model at hadron colliders 张仁友 中国科学技术大学.

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Presentation on theme: "In the R-parity violating SUSY model at hadron colliders 张仁友 中国科学技术大学."— Presentation transcript:

1 in the R-parity violating SUSY model at hadron colliders 张仁友 中国科学技术大学

2 R=(-1) 2S+L+3B SUSY new parity partially R-parity violation (RPV) i.e. non-simultaneous L and B violation in general super-potential Phenomenology: + neutrino-oscillation + stable Proton + scalar sneutrino resonance production and LFV decay Theoretical Motivation ’

3 LFV process @Tevatron/LHC: --- sneutrino resonance effect in e  can be experimentally detected sneutrino contribution (s-channel)squark contribution (u-,t-channel) --- s-channel decouple with u-channel

4 Two decoupled contributions of sneutrino and squark:

5 CompHep + Pythia d  of e  inclusive Not back-to-back!--- --- Large luminosity at the LHCglupn-gluon fusion subprocess! --- the QCD correction is quite significant in the high PT region! kinematic cuts: Why need NLO QCD corrections?

6 Contributions up to O(  s ) NLO 1.The Leading Order cross section 2. Virtual O(  s ) one-loop corrections 3. Real gluon emission corrections 4. Real light-quark emission corrections 5. Higer order gluon-gluon fusion contribution

7 Numerical result Inputs:

8 -- K-factor vs sneutrino mass at Tevatron and LHC 1.28~1.79 Tevatron 1.32~1.58 LHC

9 -- Distribution of the transverse momentum of positron

10 NLO QCD correction CompHep + Pythia d  of e  inclusive

11 -- gluon fusion contribution Large luminosity of soft gluon will contribute to low mass region <1%

12 -- Distribution of the electron-muon invariant mass a high threshold cut on electron-muon invariant mass !

13 1.The first two generations of sneutrino are much heavier than the third one. In order to simplify calculation, we take following assumptions: 2.Applying a high threshold cut on electron-muon invariant mass. (50 GeV) 3.Applying the naive fixed-width scheme in the sneutrino propagator. (10 GeV) 4. Setting decoupled squark and gluino section. (1 TeV !)

14 In our investigating parameter space the K-factors vary in the ranges of [1.182,1.643] and [1.335,1.614] at the Tevatron and the LHC, respectively.

15 Uncertainty investigation

16 The relative error of K-factor induced by the factorization scale: 0.17%(3.1%) 100 GeV 1.8% (1.3%) 250 GeV 3.0%(0.46%) 500 GeV The relative error of K-factor induced by the PDF: 6.0% (5.8%) 100 GeV 7.8% (5.0%) 250 GeV 14.2%(5.9%) 500 GeV

17 -- qT distribution

18 Conclusions 1. K -factor to be 1.2 ~ 1.8 at Tevatron and LHC; the main uncertainty comes from pdf. 2. High order gluon fusion should be accounted @LHC. 3. The distribution of the transverse momentum of final e- muon pair by resummating the logarithmically-enhanced terms for soft gluon can be a reference for future experimental analysis.


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