Explaining the lepton non-universality at the LHCb and CMS within a unified framework
Received: September
Explaining the lepton non-universality at the LHCb
Sanjoy Biswas 0 1 4 6 7 8
Debtosh Chowdhury 0 1 4 7 8
Sangeun Han 0 1 2 5 7 8
Seung J. Lee 0 1 3 5 7 8
0 335 Gwahak-ro , Yuseong-gu, Daejeon 305-701 , Korea
1 Piazzale Aldo Moro 2 , I-00185 Rome , Italy
2 Center for Theoretical Physics of the Universe , IBS
3 School of Physics, Korea Institute for Advanced Study
4 Istituto Nazionale di Fisica Nucleare , Sezione di Roma
5 Department of Physics, Korea Advanced Institute of Science and Technology
6 Dipartimento di Fisica, Universit`a di Roma La Sapienza
7 Open Access , c The Authors
8 [81] J. Alwall, M. Herquet , F. Maltoni, O. Mattelaer and T. Stelzer, MadGraph 5: going beyond
The recent results from the LHCb in the context of (B+ and the CMS analysis in the context of right handed W -boson (WR) search show a 2.6 and a 2.8 deviations from the Standard Model expectations respectively. In this work, we address these two seemingly uncorrelated results in the context of R-parity violating supersymmetry. We found that a particular combination of LQDc-type operators which successfully explain the LHCb result, can also accommodate the CMS excess in the eejj ArXiv ePrint: 1409.0882
Supersymmetry; Hadron-Hadron Scattering; Beyond Standard Model; B
-
channel of the WR search.
physics, Rare decay
1 Introduction 2 3 4
Model: RPV SUSY
Lepton non-universality at the LHCb
Lepton non-universality at the CMS
Results and discussion
The recent LHCb measurement has observed [1] a significant deviation from the standard
low invariat mass region (1 GeV2
of 3 fb1 integrated luminosity.
M`` 6 GeV2) of the di-lepton pair using a data set
More interestingly, CMS analysis for the right-handed W -boson (WR) search has also
come up with a significant deviation from the standard model expectation [3]. The CMS
search uses pp collision data at the Large Hadron Collider (LHC) at a center of mass
enhas also reported a possible excess in the context of the di-leptoquark search [4]. The
There have already been quite a few studies in an attempt to explain these results
separately assuming different models. In ref. [5], the authors studied the observed value of
RK in the context of effective operator approach, illustrated with two leptoquark models.
They also mentioned that the leptoquark couplings considered there, can correspond to
certain R-parity violating (RPV) supersymmetric scenario. However the flavor structure of
those couplings can not address the CMS eejj excesses. Certain constraints have been put
on these effective operators in [6]. On the other hand, the CMS excess in the context of both
WR and di-leptoquark search is interpreted in [7] with a resonant coloron production and
further decay of the coloron into a pair of leptoquark and in [8], with resonant production
of vector like leptons via W 0 /Z0 vector boson. A similar analysis [9] with W 0 /Z0 has been
performed in the context of WR search. Refs. [10, 11] showed that the WR excess can be
explained within the context of GUT models. Within the framework of R-parity violating
supersymmetry (SUSY) an explanation via resonant slepton production has been provided
in [12] in the context of CMS WR search. In ref. [13] the di-leptoquark excess is explained.
Though it is quite preliminary to jump into any conclusion before a more detailed
analysis of the data and despite of the fact that the statistics is very low in the case of
CMS analyses, one can still take these deviations at their face value in order to ensure a
better search strategies either to claim a discovery or to put an exclusion limit. It is worth
noting that while there are individual explanations for each of these results mentioned
above, so far there has been no attempt to have explain both simultaneously. In this
article we present a unified framework which can accommodate both the LHCb and the
CMS WR search results in the context of the RPV minimal supersymmetric standard
model (MSSM). Given the fact that the deviation in the measured value of RK can be
consistent with new physics (NP) either in the electron or in the muon sector due to the
large theoretical uncertainties present in the SM expectations, in this article, we focus on
the former possibility motivated by the observed CMS excess.
The remaining of the paper is organized as follows: in section 2, we give a brief account
of the RPV model. Section 3 describes both the B-physics and collider consequences of
this model. Finally, we summarize our results and conclude in section 4.
Model: RPV SUSY
In this section, we will give a brief review of R-parity violating SUSY scenario. While
R-parity conserving SUSY has many judicious features, which made it one of the most
popular frameworks, R-parity violating SUSY [1418] provides an alternative. It can relax
the naturalness bound from LHC due to the absence of large missing transverse energy
(ET ) signature and at the same time provides rich collider phenomenology. In MSSM, the
RP (...truncated)