The ALEPH detector at LEP is used to study single photon events in e+e- collisions at the Z resonance. In a total data sample of 15.7 pb-1 taken in 1990 and 1991 scanning the resonance, 400 events were recorded where each has a single deposition of more than 1.5 GeV measured in the polar angular region | cosθγ | < 0.74 of the electromagnetic calorimeter. It is shown that this number of events cab be accounted for by known processes. After subtraction of background events, the invisible width of the Z is determined to be 45 ± 34(stat.) ± 34(syst.) MeV. Using Z. resonance parameters derived by ALEPH, the corresponding number oflight neutrino generations is found to be 2.68 ± 0.20(stat.) ± 0.20(syst.).

Buskulic, D., Debonis, I., Decamp, D., Ghez, P., Goy, C., Lees, J., et al. (1993). A direct measurement of the invisible width of the Z from single photon counting. PHYSICS LETTERS. SECTION B, 313(3-4), 520-534 [10.1016/0370-2693(93)90027-F].

A direct measurement of the invisible width of the Z from single photon counting

CARPINELLI, Massimo;
1993

Abstract

The ALEPH detector at LEP is used to study single photon events in e+e- collisions at the Z resonance. In a total data sample of 15.7 pb-1 taken in 1990 and 1991 scanning the resonance, 400 events were recorded where each has a single deposition of more than 1.5 GeV measured in the polar angular region | cosθγ | < 0.74 of the electromagnetic calorimeter. It is shown that this number of events cab be accounted for by known processes. After subtraction of background events, the invisible width of the Z is determined to be 45 ± 34(stat.) ± 34(syst.) MeV. Using Z. resonance parameters derived by ALEPH, the corresponding number oflight neutrino generations is found to be 2.68 ± 0.20(stat.) ± 0.20(syst.).
Articolo in rivista - Articolo scientifico
ALEPH detector
English
1993
313
3-4
520
534
none
Buskulic, D., Debonis, I., Decamp, D., Ghez, P., Goy, C., Lees, J., et al. (1993). A direct measurement of the invisible width of the Z from single photon counting. PHYSICS LETTERS. SECTION B, 313(3-4), 520-534 [10.1016/0370-2693(93)90027-F].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/390411
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