Gauge bosons (W/Z)

A report to the PDG Advisory Committee

Carlo Caso & Atul Gurtu INFN, Genova TIFR, Mumbai

(Encoders/Overseers)

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Introduction

• CC+AG: 12 years coverage of W/Z, 1992–2004

• Except 1994-96 when we covered only the Z

• Will mention here the evolution of statistics, current status and then what is expected from now (November 2004) to March 2006 when the next hardcopy edition will be finalized.

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Evolution of statistics• Papers read:1992 1994 1996 1998 2000 2002 2004 2006(Oct) ? 80 86 93 98 83 31 20

• Nodes (Particle properties): 1992 1994 1996 1998 2000 2002 2004 Z 47 75 107 128 134 134 140 W 14 14 15 28 30 30

• Pages in RPP 1992 1994 1996 1998 2000 2002 2004 Z 7 13 15 18 18 20 21W 2 3 3 5 7 7 7 (*) Five disfavored TGC related nodes discarded

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Coding and data entry

• Literature search => CC & AG read papers independently and make notes.

• Comparison => exchange and compare notes; decide action on each paper via e-mail/meeting at CERN

• Code the data as ps/pdf file; exchange file; check it

• ps/pdf file to LBNL (Betty/Piotr) for entry; sends back to CC & AG for checking and correction if needed.

• Sent to verifiers. Evaluate and include their comments/ suggestions as needed.

• Enter non-PDF fit results. Update/ write new mini-reviews.

FINALIZE AND LAST CHECK AT LBNL.

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Brief recapitulation

• 1992-2002: period of intense activity in W/Z, with LEP (ADLO), SLC (SLD), TEVATRON Run-I (CDF,D0) producing a torrent of data and publications.

• The number of NODES and PAGES in RPP increased by a factor of 3.

• LEP: to match the huge statistics, the systematic errors had to be reduced & for combining results from four experiments obtained over several years, special averaging procedures were devised to account for correlated errors.

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Working groups

• To devise proper averaging procedures to account for correlations - between experiments (same beams/M.C. models/ theory input to extract

measurements) - between different data runs/ years - due to use of > 1 measurements within a fit to extract the best value of a

quantity

• LEP Electroweak Working Group; LEP W-group Klaus Monig => CC for Z -> b bbar/c cbar AG for Z-lineshape, W-mass, branching ratios THIS LEP WG=PDG INTERFACE PLAYED A CRITICAL ROLE

OVER THE YEARS.

• Now TEVATRON EWWG has taken shape and would play a similar role when RUN-II data is analyzed and published.

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Mini-reviews

• PDG: Providing world averages a crucial task (most quoted reference).

• Consequence of complicated averaging procedures: Long mini-reviews as explanations. Notes on Z-boson, W-mass.

• Mini-reviews also useful to

Clarify terminology, give latest preliminary results on important quantities.

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Mini-reviews - 2

• Other mini-reviews:

on W-TGC’s (gamma WW, ZWW),

ZZ gamma, Z gamma gamma, ZZV Couplings

Anomalous W/Z Quartic couplings.

• All are revised for every hardcopy/WEB edition, and a new one written if necessary.

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Status in RPP 2004

• Z: line-shape and lepton forward-backward asymmetry related data finalized in RPP 2002.

• Had expected ALL LEP papers (W and Z) to be finalized by end-2003 in time for RPP-04, but some analyses remain to be published:

LEP1: Z -> heavy flavor (b,c);

LEP2: Final papers on W related measurements

SOME ARE NOW COMING (OCT 04 LIST)

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

W-mass

• This is an IMPORTANT remaining quantity from LEP2. And requires a complicated analysis to obtain the best LEP value.

• 4 measurements at threshold + 4 x No of energy points (7) direct W-mass measurements from qqqq and qql nu channels.

• To use inter-year, inter-channel, inter-experiment correlations of systematic errors due to ISR/FSR, hadronisation, detector systematics, LEP beam energy, BE effects,color reconnection: LEP W-MASS

• Combine with Tevatron (CDF + D0) + UA2 to obtain world average W-mass measurement

• Finally combine with Mw/Mz, Mz – Mw, Z-mass measurements to obtain the

BEST WORLD average W-mass

Carlo Caso & Atul Gurtu: Report on W/Z to PDG Advisory Committee, LBNL, 14 November 2004

Expectations for 2005-06

• Final LEP papers on Z -> b/c and W BR’s now coming in (Oct 04 list).

• Expect W-mass papers from LEP to be coming soon.

Very likely:• All LEP inputs are in by time of the 2005

Web update• Tevatron RUN-II papers for RPP 2006