ProspectsforSUSYandUED

Introduction

This note presents an evaluation of the discovery potential of Supersymmetry and Universal Extra Dimensions for channels with jets, leptons and missing transverse energy. The LHC running scenario at a centre-of-mass energy of 10 TeV, delivering an integrated luminosity of $200 {pb}^{-1}$ for the 2009-2010 run is investigated. The ATL-PHYS-PUB-2009-084 note can be found here

Figure 1

Figure 1: Parameters of the pMSSM with constraints grid. Shown are (from top to bottom) the distribution of $\tan \beta$, the mass of the gluino versus the mass of the light squarks, the mass of the $\chi_{0}^{1}$ and the mass of the $\tilde{t}_{1}$. The lowest plot shows the distribution of the various types of nLSP for the same pMSSM models.

Figure 2

Figure2: Number of events expected for 200 $\rm{pb}^{-1}$ in 0-lepton channels and multi-leptons channels after preselection for the main background processes and the SUSY signal SU4.

Figure 3

Figure3: Effective mass distributions for the 2 jet (upper plot), 3 jet (middle plot) and 4 jet channel (lower plot) with 0 leptons.

Figure 4

Figure 4: Missing transverse energy distributions for the 4 jet channel with 0 leptons.

Figure 5

Figure5: Effective mass distributions for the 2 jet (upper plot), 3 jet (middle plot) and 4 jet channel (lower plot) with 1 lepton.

Figure 6

Figure6: Effective mass distributions for the 2 jet (upper plot), 3 jet (middle plot) and 4 jet channel (lower plot) with 2 leptons with opposite sign (OS) charge.

Figure 7

Figure 7: $M_T$ distributions for the 4 jet channel with 1 lepton.

Figure 8

Figure 8: $5\sigma$ discovery reach as a function of $m_{0}$ and $m_{1/2}$ for $\tan \beta =10$ mSUGRA scan for channels with 0, 1 and 2 leptons. Only the channels with the largest discovery reach are shown for each lepton multiplicity.

Figure 9

Figure 9: 5\sigma$ discovery reach as a function of $m_{0}$ and $m_{1/2}$ for $\tan \beta =50$ mSUGRA scan for channels with 0 and 1 leptons.

Figure 10

Figure 10: The points of the pMSSM grids with constraints as a function of the total cross section and the minimal SUSY mass (upper plot) and as a function of the minimal mass of the light squarks and the mass of the gluino (lower plot).

Figure 11

Figure 11: Significance $\sigma$ as a function of $1/R$ for the Universal Extra Dimensions scenario, taking into account channels with 0, 1 and 2 leptons.

Table1

Process	Generator	Simulation	$N_{\rm points}$	$N_{\rm events}$ per point
mSUGRA	$\tan \beta =10$	HERWIG 6.5 ATLFAST2	76	30000
mSUGRA	$\tan \beta =50$	HERWIG 6.5 & ATLFAST2	23	30000
pMSSM constraints	PYTHIA 6.4	ATLFAST1	150	30000
UED	PYTHIA 6.4	ATLFAST2	8	5000-100000

Table1: The Monte Carlo generator, detector simulation programme, the number of points in parameter space per model, and the number of events per point for all signal samples.

Table2

Process	Generator	$N_{events}$	$\sigma * BR * \it{eff}$	Simulation
$W \rightarrow \mu\nu$ + jets	ALPGEN+JIMMY	1635166	13237.30	ATLFAST2
$W \rightarrow \tau\nu$ + jets	ALPGEN+JIMMY	2113632	13233.00	ATLFAST2
$W \rightarrow e\nu$ + jets	ALPGEN+JIMMY	3110747	13249.00	ATLFAST2
$WW$	gg2WW +JIMMY	52391	0.28	GEANT4
\ttbar($\ell\nu qq$ + $\ell\nu\ell\nu$)	MC@NLO+JIMMY	3327021	202.86	GEANT4
\ttbar($qqqqbb$)	MC@NLO+JIMMY	3685781	170.74	ATLFAST2
\Wminus\Zboson	MC@NLO+JIMMY	16807	21.75	GEANT4
\Wplus\Wminus	MC@NLO+JIMMY	41108	7.14	GEANT4
\Wplus\Zboson	MC@NLO+JIMMY	7286	37.28	GEANT4
\Zboson \rarrow $\mu\mu$ + jets	ALPGEN+JIMMY	605000	1204.20	ATLFAST2
\Zboson \rarrow $\nu\nu$ + jets	ALPGEN+JIMMY	2399496	7056.30	ATLFAST2
\Zboson \rarrow $\tau\tau$ + jets	ALPGEN+JIMMY	566498	1211.00	ATLFAST2
\Zboson \rarrow ee + jets	ALPGEN+JIMMY	635835	1206.10	ATLFAST2
\Zboson\Zboson	MC@NLO+JIMMY	13456	18.41	GEANT4
QCD bb $(140<p_{T}<280)$	ALPGEN+JIMMY	45000	4384.20	ATLFAST2
QCD bb $(35<p_{T}<70)$	ALPGEN+JIMMY	70000	7522.42	ATLFAST2
QCD bb $(70<p_{T}<140)$	ALPGEN+JIMMY	289999	29119.15	ATLFAST2
QCD bb $(p_T>280)$	ALPGEN+JIMMY	57467	186.80	ATLFAST2
QCD udsc $(140<p_{T}<280)$	ALPGEN+JIMMY	1821843	182230.10	ATLFAST2
QCD udsc $(35<p_{T}<70)$	ALPGEN+JIMMY	2827992	375056.88	ATLFAST2
QCD udsc $(70<p_{T}<140)$	ALPGEN+JIMMY	1390216	1193879.82	ATLFAST2
QCD udsc $(p_T>280)$	ALPGEN+JIMMY	1938961	7210.30	ATLFAST2
Single top ($Wt$ + tchan)	AcerMC	14281	55.53	GEANT4

Table2 : Summary of Standard Model datasets used in this analysis. The QCD samples are subdivided according to the $p_T$ (GeV) of the leading jet and the type of quark produced. $N_{events}$ is the sum of MC weights, i.e. weight = \pm1$ for events produced with the MC@NLO generator. The cross section reduced by the branching ratio and the generator level filter efficiency is $\sigma * BR * eff.

Table3:

The number of background and SU4 events for the plots Figure 3-5 can be found here: number_of_events.txt

---

Major updates:
-- JanetDietrich - 2009-08-27

Responsible: JanetDietrich
Last reviewed by: Never reviewed