Diffractive Higgs Production at the Tevatron and LHC
http://www.pomwig.com
• Do we all disagree, and, if so, why?• How sensitive are the predictions to the parameters of
the pomeron trajectory?• Can we check the LHC predictions in Run II?
Phys. Lett. B 540 (2002) 263-268
Brian Cox, Jeff Forshaw and Beate Heinemann
Workshop on low x physics, Antwerp 2002
WHAT IS POMWIG ?
• No doubt that Ingelman – Schlein works at HERA
• Pomwig uses measured structure functions and flux from H1 OR user defined structure functions / flux PLUS all HERWIG hard sub-processes / hadronisation etc.
What do we calculate?
Khoze, Martin & Ryskin, hep-ph/0207313
“Inclusive” (Central-inelastic) process
p+p p + gap + H + X + gap + p
What do we calculate?
Results
CDF measured 44 20 nb
S2 = 0.1
S2 ~ 0.02 ~6fb
Enberg ~ 2 fb
Higgs cross sections
IP + IR, IP= 1.20, IR=0.57 (POMWIG defaults) ,
MH = 115 GeV
What effect does the intercept have?
H1 fit 2
S2 = 0.02
S2 = 0.1
(CDF data)
Theory:
S2 = 0.05
Khoze, Martin & Ryskin, hep-ph/0207313
fb fb
Are these diagrams as large a contribution as KMR calculate?
Can we see the exclusive contribution in the data?
Exclusive limit ~ 3.7 nb CDF Phys. Rev. Lett 85 4215 (2000)
Exclusive calculation ~ 1 nb (Khoze, Martin & Ryskin, hep-ph/0111078, 0006005)
Appleby & Forshaw, Phys.Lett.B451 108-114 (2002)
POMWIG does well at differential distributions
Mass dist. similar
(KMR hep-ph/0207313)
Exclusive vs. C.inel
• Cross section depends critically on invariant mass of diffractive system (and available phase space for emission)
Mass POMWIG
(C.inel)
KMR exclusive(hep-ph/0111078)
~20 GeV(dijets ET > 7 GeV)
33nb (CDF cuts) 1nb
~70 GeV(dijets ET > 25GeV)
8nb (CDF cuts)
230nb (~ < 0.1) 60nb115 GeV(Higgs)
0.02fb 0.2fb
consistent with CDF data
KMR cuts:
IP
IP+IR
CDF cuts:
0.035 < < 0.095
0.01 < < 0.03
IP
IP+IR
Summary fb fb
• KMR and CFH agree, but CFH miss out LO piece, accounted for by larger gap survival factor
•BDPR very large – can’t be accounted for by lower IP intercept
• crucial (and possible) to observe exclusive dijet production in different mass ranges (~1 nb ET > 7 GeV) at Run II to check these conclusions.
