We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK


93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Measurement of the energy dependence of hadroni...
View graph of relations

« Back

Measurement of the energy dependence of hadronic jet rates and the strong coupling asαs from the four-jet rate with the DELPHI detector at LEP

Research output: Contribution to journalJournal article


Journal publication date01/2005
JournalEuropean Physical Journal C: Particles and Fields
Number of pages14
Original languageEnglish


Hadronic events from the data collected with the DELPHI detector at LEP within the energy range from 89 GeV to 209 GeV are selected, their jet rates are determined and compared to predictions of four different event generators. One of them is the recently developed APACIC++ generator which performs a massive matrix element calculation matched to a parton shower followed by string fragmentation. The four-jet rate is used to measure αs in the next-to-leading-order approximation yielding αs(M2Z ) = 0.1175 ± 0.0030. The running of αs determined by using four-jet events has been tested. The logarithmic energy slope is measured to be dα−1 s d logEcm = 1.14 ± 0.36. Since the analysis is based on four-jet final states it represents an alternative approach to previous DELPHI αs measurements using event shape distributions.

Bibliographic note

Author list is partial - see original article for full author list.