Search for stopped gluinos from pp collisions at square root s = 1.96 TeV

Area of Science:

• Particle Physics
• Beyond Standard Model Physics
• Supersymmetry

Background:

• Models beyond the Standard Model predict long-lived, heavy particles.
• These particles, like the gluino, may hadronize and decay long after production.
• Direct searches for such delayed decays are crucial for model validation.

Purpose of the Study:

• To perform the first direct search for delayed decays of stopped gluinos.
• To set limits on the production cross-section and decay branching ratio of gluinos.
• To probe gluino and neutralino masses within split supersymmetry models.

Main Methods:

• Analysis of approximately 410 pb(-1) of proton-antiproton collisions at sqrt(s) = 1.96 TeV from the Fermilab Tevatron Run II.
• Utilizing the D0 detector to identify signatures of stopped gluinos decaying into a gluon and a neutralino.
• Searching for decay events not synchronized with accelerator bunch crossings, up to 100 hours post-production.

Main Results:

• Limits are placed on the product of gluino cross-section, probability to stop, and branching ratio for the decay g --> g chi(1)(0).
• These limits are presented as a function of gluino and neutralino masses.
• The search covers gluino lifetimes ranging from 30 microseconds to 100 hours.

Conclusions:

• This study provides the first direct experimental constraints on long-lived gluinos.
• The results constrain parameters within split supersymmetry models.
• The search demonstrates sensitivity to heavy, long-lived particles decaying significantly after their production.