Diffractive Higgs Production at the Tevatron and LHC Do we all disagree, and, if so, why? How sensitive are the predictions to the.

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.