From: SMTP%"Doreen.Wackeroth@psi.ch" 9-OCT-1999 19:46:53.25 To: GIAMPIERO CC: Subj: RE: DDRW results for LEP2 workshop Date: Sat, 9 Oct 1999 19:41:29 +0200 (MET DST) From: Doreen Wackeroth To: GIAMPIERO@to.infn.it Cc: Ansgar Denner , Stefan Dittmaier , Markus Roth Subject: RE: DDRW results for LEP2 workshop In-Reply-To: <991008105042.246004b8@to.infn.it> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear Giampiero, finally, here are our results for the total cross sections without imposing any cuts. We provide two values for the Born cross section, denoted by 'full' when we take into account all contributing diagrams and denoted by 'CC03' when only the WW signal diagrams are considered. Our corrected cross section, denoted by 'Best', comprises the 'full' Born and the 'full' O(alpha) corrections (i.e. virtual corrections in DPA+complete real photon contribution). As you might already know, we wrote two independent MCs, which mainly differ in the method used to cope with the arising soft and collinear singularies. The results of the MC which uses the subtraction method are denoted by 'sub.', and 'ps.sl.' denotes the results when using phase space slicing. As far as the total cross section is concerned, the subtraction method yields much smaller statistical errors than phase space slicing for the same number of events. This is due to the very small technical cuts imposed on the 2->5 phase space in order to isolate the soft and collinear regions in case of ps.sl.. To obtain a comparable accuracy, MC(ps.sl.) needs higher statistics, but since time is running out I just send you the present ps.sl. numbers for the sake of completeness. E_CMS = 200 GeV (no cuts, 10^7 events) Born: xs_tot [pb] Best: xs_tot [pb] CC03 full full sub.: 1.97733+-0.00079 1.97884+-0.00085 1.78938+-0.00085 u d~ s c~: [ps.sl.: 1.97740+-0.00080 1.98030+-0.00081 1.79096+-0.00165] sub.: 0.65911+-0.00026 0.65957+-0.00028 0.59700+-0.00031 u d~ mu- v_mu~: [ps.sl.: 0.65913+-0.00027 0.66009+-0.00027 0.59668+-0.00057] sub.: 0.21970+-0.00009 0.21984+-0.00009 0.19914+-0.00010 v_mu mu+ tau- v_tau~: [ps.sl.: 0.21971+-0.00009 0.22001+-0.00009 0.19892+-0.00023] Input: ------ alpha(0) = 1/137.035989, alpha(mz) = 1/128.88700, alpha_s = 0.11900, gfermi = .1166370E-04, mw = 80.35000, mz = 91.18670, mh = 150.00000, gamw = 2.08699, gamz = 2.49471, me = .51099907E-03, mmu = 0.105658389, mtau = 1.77705, mu = 0.04850, mc = 1.55000, mt = 174.17000, md = 0.04850, ms = 0.15000, mb = 4.50000. where gamw is the calculated, 1-loop corrected W boson width. We work in the G_mu scheme, i.e. we replace alpha(0) by alpha(0)=sqrt(2)*gfermi/pi*mw**2*sw**2 everywhere, with sw**2=1-(mw/mz)**2. Thanks a lot for your patience. Cheers, Doreen -------------------------------------------- D. Wackeroth Department of Particles and Matter Theory Group, WHGA/128 Paul Scherrer Institute CH-5232 Villigen PSI, Switzerland phone: +41 56 310 4222 fax: +41 56 310 3294 E-mail: Doreen.Wackeroth@psi.ch http://www.hep.psi.ch/wackerot/index.html ---------------------------------------------