Phenomenology of a Triplet Higgs and Searching for a MSSM Higgs in Diffraction

$Phenomenology of a Triplet Higgs and Searching for a MSSM Higgs in Diffraction$

Phenomenology of a Triplet Higgs and Searching for a MSSM Higgs in Diffraction

XXXVIIIth Rencontres de Moriond QCD & High Energy Hadron Interactions Triplet Higgs Model: How to avoid a light higgs boson.

MSSM Higgs with CP violation: How to have a very light higgs boson.

Triplet Model: with B. White, D. Ross, A. Sabio-Vera JHEP 0110:007,2001; hep-ph/0302256.

MSSM Higgs: with B. Cox, J-S. Lee, J. Monk, A. Pilaftsis. hep-ph/0303206 Precise data (0.1%) from LEP/SLC/Tevatron imply a light Higgs boson when interpreted within the Standard Model: 53 mh 87 34 GeV

Similar conclusions in SUSY extensions (< 130 GeV).

See lepewwg.web.cern.ch [Blank & Hollik] I ntroduce a real triplet (Y= 0):

v 246 GeV Mass spectrum 2 MW 1 2 2 2 M Z cos W cos 2 2 mh 1v 2 2 2 mk m 4v /

0 3 2 4 / 4

2 m mk m v [Custodial symmetry]

One-loop RG analysis reveals model is well defined up to 1 TeV. Mass splitting need not be much smaller than v if appreciable mixing in neutral sector. Oblique Corrections i.e. not vertex or box

(q) g (q2 )

(m) (m2 ) (0)

[Lynn, Stuart; Peskin, Takeuchi] S, T and U are gauge invariant and finite:

SM (mh ) ASM S({mi }) BSM T ({mi }) CSM U ({mi })

General observable New physics enters only via S, T and U

In the triplet model we work to lowest order in

Hence quantum corrections are negligible: S 0 No hypercharge T 0 Custodial symmetry But tree level corrections are interesting:

• Direct correction to W mass since

2 2 2 2 MW M Z cos W (1 )

2 • Indirect correction to all observables since tree level

SM 2 GF GF (1 )

SM (mh ) ASM STM (mk ,m ) BSM ( TTM (mk ,m ) tree )

CSM UTM (mk ,m ) Tree Level Effects

95% CL contour

Standard Model ref mh 100 GeV Tree level violation of custodial symmetry can permit the lightest higgs to be as heavy as 500 GeV.

There are other ways to accommodate a heavier higgs boson: [Peskin & Wells]

• S < 0 extra SU(2)xSU(2) multiplets [Dugan & Randall] new singlet majorana fermions [Gates & Terning]

• T > 0 4th generation [e.g. Dobrescu & Hill] 2 higgs doublets [Chankowski et al] MSSM with CP Violation Higgs sector CP violation natural Since the soft SUSY breaking trilinear couplings and gaugino masses can be complex

(h, H, A) (H1, H 2 , H3 ) Easy to arrange for lightest higgs to have weak coupling to Z Hence it may not have been seen at CERN

[Pilaftsis; Carena, Ellis, Pilaftsis, Wagner] Carena, Ellis, Pilaftsis, Wagner Difficulties in detecting such a light higgs at Tevatron and LHC via conventional search channels. Especially since lightest higgs also has weak coupling to top.

Dedicated LEP analysis underway in an attempt to exclude the low mass regions.

Possibility to look in diffraction. KMR predict 3 fb for a 115 GeV higgs includes gap survival factor 1/50 LHC: 100 fb 1

Decay to b quarks viable since QCD background is heavily suppressed

m 1 GeV (tagged protons needed)

S/B > 1 anticipated (de Roeck et al) [Khoze, Martin & Ryskin]

Crucial to measure “exclusive” dijets at Run II to ascertain the reliability of the theoretical calculations. Diffractive Higgs production cross-section at LHC (solid) and Tevatron (dotted). MSSM parameters chosen to lie in the region not currently excluded by LEP, i.e. 3 tan 5 m 60 GeV H1 Tevatron: 10 fb 1 Conclusions Rate is certainly high enough to be explored at LHC, maybe even at Tevatron.

Central production may prove to be a useful tool which is able to complement more traditional search strategies.

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