Search for Excited Quarks in ep Collisions at HERA

A search for excited quarks is performed using the full e±p data sample collected by the H1 experiment at HERA, corresponding to a total integrated luminosity of 475 pb−1 . The electroweak decays of excited quarks q∗→qγ , q∗→qZ and q∗→qW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q∗ production cross sections and on the ratio f/Λ of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches.

Note:

Revised version, with small changes to the text. 19 pages, 5 figures

electron p: interaction
positron p: interaction
quark: excited state
coupling: mass dependence
H1
DESY HERA Stor
excited state: decay
intermediate boson: decay modes
channel cross section: branching ratio: upper limit
model: composite

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