Search for third-generation scalar leptoquarks decaying to a top quark and a lepton at

Area of Science:

• High Energy Physics
• Particle Physics
• Beyond Standard Model Physics

Background:

• Leptoquarks (LQs) are hypothetical elementary particles that couple to both quarks and leptons.
• Searches for new phenomena beyond the Standard Model are crucial for understanding fundamental physics.
• Scalar leptoquarks decaying to a top quark and a tau lepton are predicted by some theories.

Purpose of the Study:

• To search for evidence of pair-produced heavy scalar leptoquarks (LQs).
• To investigate LQ decays into a top quark and a tau lepton.
• To set exclusion limits on the production cross section and mass of these leptoquarks.

Main Methods:

• Analysis of proton-proton collision data collected by the CMS detector at the LHC.
• Selection of final states involving electrons or muons, hadronic tau leptons, and jets.
• Statistical analysis to set upper limits on the LQ production cross section.

Main Results:

• No significant excess of events consistent with pair-produced scalar leptoquarks was observed.
• Upper limits were placed on the production cross section as a function of LQ mass.
• Scalar leptoquarks decaying to a top quark and a tau lepton with masses below 900 GeV were excluded at 95% confidence level.

Conclusions:

• The search provides the most stringent limits to date for scalar leptoquarks decaying to a top quark and a tau lepton.
• The results constrain theories predicting such leptoquark states.
• Further searches with increased luminosity and improved analysis techniques may probe higher mass ranges.