A coffee-time challenge

Can you tell a Z from a WW? The Bulletin is offering a prize for deciphering LEP events on show in Restaurant No. 1.

If you’ve been to the coffee areas in Restaurant 1 you’ve probably noticed the ‘LEP event’ table tops, installed for the symposium and exhibition ‘From the Proton Synchrotron to the Large Hadron Collider - 50 Years of Nobel Memories in High-Energy Physics’.

There are 16 events in total (in two areas), four from each of the four LEP experiments, and they include examples of different particle decays observed at LEP during its 11 years of operation. The list below indicates the decay channels represented.

We are offering a prize of the ATLAS pop-up book, ‘Voyage to the Heart of Matter’, for the correct identification of all 16 events. Entries should indicate the table number corresponding to each of the decays listed.

There will be a draw on 19 January to pick the winner from entries that correctly identify all 16 events.

Please email your answers to

Z → e+e- WW → eυμυ
Z → μ+μ- WW → μυμυ
Z → τ+τ- WW → τυτυ
Z → quark-antiquark WW → τυμυ
Z → quark-antiquark-gluon WW → quark-antiquark μυ
ZZ → e+e- μ+μ- WW → quark-antiquark eυ
ZZ → quark-antiquark e+e- WW → quark-antiquark τυ
ZZ → quark-antiquark μ+μ- WW → quark-antiquark quark-antiquark



by CERN Bulletin