Abstract
We propose a new search strategy based on the event shape variables for new physics models where the separations among the masses of the particles in the spectrum are small. Collider signature of these models, characterized by low pT leptons/jets and low missing pT, are known to be difficult to look for. The conventional search strategies involving hard cuts may not work in such situations. As a case study, we have investigated the hitherto neglected jets+missing ET signature – known to be a challenging one – arising from the pair productions and decay of n=1 KK-excitations of gluons and quarks in the minimal Universal Extra Dimension (mUED) model. Judicious use of the event shape variables enables us to reduce the Standard Model backgrounds to a negligible level. We have shown that in mUED, R−1 up to 850 GeV can be explored or ruled out with 12 fb−1 of integrated luminosity at the 7 TeV run of the LHC. We also discuss the prospects of employing these variables for searching other beyond Standard Model physics with compressed or partially compressed spectra.
Highlights
One of the main goals of the ongoing LHC experiment at CERN is to find out any new dynamics that could be operative at the energy scale of Tera electron volts (TeV) among the elementary particles
On the other hand using a typical value of K = 1.5 for the signal, we find that even if the over all K-factor of the background is 3, the significance computed from the leading order (LO) cross section will reduce by 0.9
We have explored the possibility of discovering the minimal Universal Extra Dimension (mUED) model at the LHC using the jets + ET channel, which among various signatures of mUED has the largest cross section
Summary
One of the main goals of the ongoing LHC experiment at CERN is to find out any new dynamics that could be operative at the energy scale of Tera electron volts (TeV) among the elementary particles. The conventional search strategies to dig out the signals of mUED from the SM backgrounds using strong cuts on visible/missing pT are not very efficient.
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