Searches for Non-SM Higgs at the Tevatron

1. Searches for Non-SM Higgs at the Tevatron Thomas Wright University of Michigan on behalf of the CDF and DØ Collaborations This talk: neutral MSSM Higgs searches More exotic Higgs to follow (M. Mulhearn) XLIIIth Rencontres de Moriond QCD and High Energy Interactions March 8-15, 2008

2. Higgs in the MSSM • In the standard model, one complex doublet = four scalar fields • Three turn into W/Z mass  one physical scalar • Minimal Supersymmetric Standard Model (MSSM) requires two doublets • One couples only to up-type fermions, the other only to down-type • Ratio of VEV’s - “tanb” • Eight scalar fields – three for W/Z mass = five physical scalars • Three neutral (h, H, A), two charged (H±) • Properties of the Higgs sector largely determined by two parameters: • mA : mass of pseudoscalar • tanb : ratio of VEV’s • Higher-order effects introduce other SUSY parameters(benchmark scenarios, see Carena et al., hep-ph/0511023) • Typically, mh < mA < mH , and mH± ~ mA • For tanb near 1, h is SM-like and light – SM Higgs limits apply • Larger tanb and light mA shows more interesting behavior

3. Higgs at High tanb 0 b b 0 b Processes involving bottom quarks (down-type) can be enhanced (goes like tan2b) Boost from femtobarns to picobarns Could be observable at Tevatron! f0 = h/H/A via top loop H = SM Higgs here, H = A or h/H

4. Higgs at High tanb Neutral sector simplifies at high tanb A and h/H become degenerate Other scalar SM-like, low cross section Only need to search for a single mass peak (f) • For the A and its twin h/H, at high tanb decays into bb (90%) and tt (10%) dominate • So, for example, won’t see enhancement in HWW* channel • CDF and DØ are searching in both of these decay modes

5. The  Channel th ID t cone isolation • Unique final state – can look for inclusive f production • Main backgrounds: Z tt, W+jets, dibosons • One tau decays leptonically: e/m (CDF) or m (DØ) (plus n’s) • pT > 10 GeV/c (CDF), 15 GeV/c (DØ) • Other tau hadronic (both) (and nt) • One or three tracks (Sqtrk = ±1), opposite to lepton • CDF : isolation 30°, shrinking t cone (10° 3°) • DØ : three types (p±, p±p0, 3-prong), NN score • No electron veto (allows em) • pT > 15 GeV/c (1-prong), 20 GeV/c (3-prong) • Also tt em (CDF), pT > 10, 6 GeV/c • Reject non-tt background • Lepton and missing energyinconsistent with W • HT cut (CDF) or kinematic NN (DØ) Multiple neutrinos  can’t reconstruct tt mass very well

6. CDF tt Results Moriond 2007, CDF 1 fb-1 mvis (GeV/c2) Last year at this time, CDF had a >2s excess around 160 GeV/c2 (<2s over all mf) Updated Fall 2007 with an additional 0.8 fb-1 of data No excess in e/m + thad channel after update mvis (GeV/c2)

7. CDF tt Results No apparent excess in em channel either Set s x BR limits mvis (GeV/c2) mvis (GeV/c2)

8. DØ tt Results Visible mass (like CDF) Just one input to search NN, along with lepton, tau kinematics Do not see any excess (as was the case last winter) Set s x BR limits

9. MSSM Interpretation DØ btt 340 pb-1 Interpret s x BR limits as limits on tanb vs mA in MSSM benchmark scenarios More data and analysis improvements on the way Project missing momentum onto t axes for boosted Higgs (improve mtt) Split into b-tagged and untagged samples (already demonstrated by DØ) Updated results from DØ in tt and btt channels coming soon!

10. The fbb Channel b quark pT >20 GeV/c, |h|<2 0 b b Dawson, Jackson, Reina, Wackeroth hep-ph/0603112 0 b • Inclusive H  bb is too hard due to QCD background • Require one additional bottom quark jet besides the two from Higgs decay • “3b” channel best compromise between signal and background rates too much background with fbb, 3b total

11. B-Jet Identification CDF • CDF : displaced vertices with Lxy/s cut • Vertex mass separation • DØ : combine vertex properties and displaced track info with NN • Tag to h beyond 2 DØ

12. DØ 3b Channel • Result with 0.9 fb-1 (2006), update coming soon! • Search uses invariant mass of the two leading jets m01 in triple-tagged events • Derive background shape from double-tagged sample • Correct for kinematic bias of third jet tag • Normalize background to data in sideband region, look inside the signal window • No excess observed, set limits on s x BR mH = 120

13. CDF 3b Channel • New result for Moriond QCD 2008, using 1.9 fb-1 • Search in mass of two lead jets m12 • Backgrounds are events with two true b-tags, and a b/c/fake tag • Characteristic m12 spectra for each • Start from bb+jet sample (corrected double-tags), weight events by flavor hypothesis • Correct bbb and bcb shapes for double/triple-tag selection bias • Largest systematic error • Fit the observed m12 spectrum with the backgrounds and a Higgs shape

14. CDF 3b Channel • Improve prediction of total background m12 using tag properties • Invariant mass of tracks in each vertex mj • m1+m2 : bbb+bbx / bcb+bqb • m3 : bbx / bbb+bcb+bqb • Unstack into 1D variable “xtags” for plotting/fitting • Fits are 2D – m12 vs xtags • Four backgrounds • Higgs signal template

15. CDF 3b Results • No significant excess observed • Set limits on s x BR • Background systematics limitingimprovement at low mH • Focus of the next round

16. MSSM Interpretation • Interpret in MSSM scenarios • Include effect of Higgs width(~20% for tanb = 100) • Lose sensitivity (lower S/B) • Lowers event yield • Best limits obtained in scenarios with m < 0 (loop enhancements)

17. Summary • CDF and DØ are looking hard for neutral MSSM Higgs bosons • Lots of progress but no discovery as of yet • Techniques are well-advanced but still room for improvement • Taus: split samples to improve mtt and S/B with b-tagging • 3b: background shape systematics (CDF) • DØ updates on all three channels (tt, btt, 3b) coming soon • Combination of experiments/channels is planned • Results today use 1-2 fb-1, expect 5-6 by 2009 (7 by 2010?) • Could probe down to tanb in the 20’s with full Run II samples • Or, with the right mA and tanb,make a discovery!

18. Backup Material

19. Charged Higgs CDF : use dilepton, l+jets (single and double-tagged), and lepton+tau s’s Consider H+ tn, cs, t*b, W+bb Map out allowed and excluded regions in mH+ vs tanb using CPsuperH and CDF simulation to predict effects on top s’s • Search in top decays • t  H+b • DØ : ration of cross sections l+jets/dilepton • BR(t  H+b) < 0.35 @ 95% CL (for H+  cs)

20. CDF tt Projections