Non-SM Higgs Searches at the TeVatron

Non-SM Higgs Searches at the TeVatron

Andy HockerFermi National Accelerator Laboratory

for the CDF and D0 CollaborationsICHEP 2006

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 2

What we’re looking forWhat we’re looking for

• Minimal supersymmetric SM Higgs bosons The neutrals: h0, H0, A0 ( = 0) The charged: H±

• Doubly-charged Higgs bosons (H±±) Part of Higgs triplet (0, H±, H±±) Appear in L-R symmetric SM extensions Can be light (~100 GeV), decay leptonically

• Extremely low backgrounds

• Fermiophobic Higgs bosons (0) Can appear in “Type III” 2HDM Fermion couplings suppressed, boson enhanced Distinct signature of decays via W triangles …but no new results here…

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 3

MSSM 0 at the TeVatronMSSM 0 at the TeVatron

•Large tan (favored by LEP2 data) enhances couplings to b-quarks,

•Most of 0 BR covered by bb (~90%),

•Production:

•Main modes are

•gg, bb0 (0bb hopeless, but not 0)

•Associated production with b’s (both decays observable)

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 4

Experimental toolkitExperimental toolkit

• Bottom-quark tagging Exploit long lifetime of B

hadrons Requires precision tracking (Si

microstrip detectors) with as much forward reach as possible

• Tau ID Hadronic decays

• Isolated, narrow jets• Requires good tracking/EM

calorimetry for charged/neutral pion reconstruction

Leptonic decays• Requires good EM cal, muon

detector coverage Large samples of Z’s/jets used

to study efficiencies/fake rates

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 5

CDF and D0 in Run IICDF and D0 in Run II

Some highlights

Si detectors (D0 just got some

more!)

Good central tracking

Forward muon systems

Trigger/DAQ

CDF: forward calorimeter

Data samples

Over 1 fb-1 in the can

Det/acc resumed operations in June, running

well

Results here range from 200-

350 pb-1

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 6

Searches for b0, bb0 (0bb)Searches for b0, bb0 (0bb)

• Start from large multijet trigger sample

• Require at least 3 jets w/ displaced secondary vertex

• Form invariant mass of two leading b-jets, look for ≈bump Shape and normalization of

bgd determined from doubly-tagged data

260 pb-1

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 7

b0, bb0 resultsb0, bb0 results

• 95% CL upper limit on xsec vs. mA

• Compare w/ predicted xsec for canonical MSSM benchmarks

• Exclusions placed in mA, tan plane

260 pb-1

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 8

Searches for 0Searches for 0

• Select ehad, had, and (at D0) e events

• Partially reconstruct Higgs via

mvis p1

vis p 2

vis p T

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 9

0 results (comb. w/ bb)0 results (comb. w/ bb)

Includes bbb(b) searches --- these are your “take-home” plots for the TeVatron

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 10

Just in from D0!Just in from D0!

• New search for (b)b0(b)b Less signal + less

background = competitive limit

Will be fruitful to combine

• Updated search for (b)bbb 0.9 fb-1

New NN b-tagger Still no signal, but ever-

tighter limits Too new for a nice mA-tan

plot

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 11

Charged Higgs in top decaysCharged Higgs in top decays

• Normally, ttWbWb Well-def’d final states

• If H± light enough, can replace one or both W’s

• BR(t Hb) and H± decays depend on tan , mH (at tree level) H± H± cs H± t*b H± W0

• Alters mix of tt final states

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 12

Indirect search for tH±bIndirect search for tH±b

• Look at event yield in 4 tt final states: lljj ljj ljjbj ljjbb

• Find joint prob to observe Ndata given expected yield for given mH, tan , etc.

• Determine exclusion areas in mH vs. “X” plane

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 13

Charged Higgs ResultsCharged Higgs Results

Indirect search from 200 pb-1 of tt in four final states

mH/tan exclusions for “no-mix” benchmark

Other benchmarks explored as well

Radiative SUSY corrections included!

New direct search for tHbb

Look for anomalous production of ttlbj (almost pure tt)

4 expected from ttWbWb, 6 observed

Limits on BR(t->Hb) assuming BR(H±) = 1

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 14

Searches forH±±e, Searches forH±±e,

• Same-sign lhad has significant background H±± pair-produced, so require additional (loose) leptons

• Counting experiment < 1 SM event expected, zero observed

CDF H++ Lower Mass Limit

e e 133 --- ---

115 136 ---

114 112 ??“stable” 134

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 15

ConclusionsConclusions

• The MSSM provides the TeVatron with a real shot at a Higgs discovery Light h0, decent xsec Decays to b,

• Null results for 0 searches put the squeeze on the MSSM from the large tan side

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BackupperyBackuppery

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Evidence/discoveryEvidence/discovery

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Searches forH±±ee, e, Searches forH±±ee, e,

• Same-sign dilepton search in 3 sigma mass windows

• Low backgrounds (limit ee search to > 100 GeV)

No candidates, lower limits from 89-136 GeV set

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 19

Searches for quasi-stable H±±Searches for quasi-stable H±±

• H±± particles that do not decay in the detector Look like highly-ionizing “muons” Large dE/dx in tracking chamber Basically, zero background… and zero observed

28-JUL-2006 A. Hocker, ICHEP '06, Moscow 20

Searches for fermiophobic h0 Searches for fermiophobic h0

Look for peaks in diphoton mass distribtution

Current results not competitive with LEP, but will be soon!