Prospects)(perspec+ves))from) Tevatron)Higgs) fileTEV,)CMS,)ATLAS) Higgs boson mass (GeV/c2) 120 140 160 180 200 220 SM! / 95%! Limit on 1 10 Observed S CL Expected ± 1! S CL Expected

Prospects (perspec+ves) from Tevatron Higgs

Ben Kilminster (Fermilab) Higgs Hun+ng workshop

July 29, 2011

1 B.Kilminster, Higgs Hun+ng

•  Prospects – What are the most interes+ng results we can expect from Tevatron with full dataset of 10 J-‐1 ?

•  Perspec+ves – What can Tevatron teach us given the recent CMS & ATLAS results ?


•  Exclusion 156 GeV – 177 GeV •  Below 115 GeV

–  Expected = observed –  Almost at SM 95% CL exclusion

•  Expected sensi+vity less than 1.35*SM across interes+ng range (114 – 155 GeV) –  Worst expected sensi+vity at 130 GeV


Most signal-‐like value

•  Most signal-‐like excess –  Consistent with 130 GeV Higgs


TEV, CMS, ATLAS

)2Higgs boson mass (GeV/c120 140 160 180 200 220

SM!/

95%

!Li

mit

on

1

10

ObservedSCL! 1± Expected SCL! 2± Expected SCL

Bayesian Observed


Bayesian Observed

-1 = 1.1 fbintCombined, L = 7 TeVsCMS Preliminary,

[GeV]Hm110 120 130 140 150 160 170 180 190 200

SM/

95%

CL

Lim

it on

1

10

Observed CLsExpected 1 ! 2 !

ATLAS Preliminary

-1 Ldt = 1.0-1.2 fb

= 7 TeVs


TEV, CMS, ATLAS


SM!/

95%

!Li

mit

on

1

10


Bayesian Observed


Bayesian Observed


[GeV]Hm110 120 130 140 150 160 170 180 190 200

SM/

95%

CL

Lim

it on

1

10


ATLAS Preliminary

-1 Ldt = 1.0-1.2 fb

= 7 TeVs


Consistencies TeV, CMS, ATLAS •  Sensi+vi+es to < ~2*SM for 125 to 200 GeV •  Exclusion above 155 GeV •  Excesses overlap 130 to 155 GeV •  CMS injected signal studies indicate 130-‐140 GeV can produce such an excess as seen in CMS & ATLAS •  Tev most signal-‐like point is 130 GeV

•  Sensi+vity at 130 GeV •  CMS : 0.8*SM •  Tevatron : 1.35*SM

•  ATLAS : 1.4*SM

TEV, CMS, ATLAS


SM!/

95%

!Li

mit

on

1

10


Bayesian Observed


Bayesian Observed


[GeV]Hm110 120 130 140 150 160 170 180 190 200

SM/

95%

CL

Lim

it on

1

10


ATLAS Preliminary

-1 Ldt = 1.0-1.2 fb

= 7 TeVs

Differences TeV, CMS, ATLAS •  Tevatron sensi+vity improves for less than 130 GeV as you go down in mass •  Opposite at CMS, ATLAS

•  LHC is > 2 Sigma high ~160 GeV •  No excess at Tevatron

•  CMS & ATLAS fluctuate high mH < 120 GeV •  Tevatron is inconsistent


•  Interes+ng regions for Tevatron to study

Low mass : ~ 115 GeV Tevatron H➞bb searches

Mid mass : ~ 130 GeV Most consistent excesses Between Tev, CMS, ATLAS


Tevatron perspec+ves

•  115 GeV –  Tevatron currently provides best sensi+vity

•  Mainly from H➞bb searches •  Can address behaviors seen in CMS, ATLAS data from H➞WW and H➞γγ

•  130 GeV –  Tevatron sensi+vity mainly from H➞WW –  Currently compe++ve with LHC –  Even when LHC has more data …

•  Tevatron H➞WW has different background composi+on •  Tevatron H➞WW has different signal composi+on

B.Kilminster, Higgs Hun+ng 9

Tevatron perspec+ve at 130 GeV


WW excesses at CMS & ATLAS

CDF , D0 plots


ATLAS 0-‐jet ATLAS 1-‐jet

CMS 0-‐jet CMS 1-‐jet

•  Tevatron can provide independent check


Could WW excesses at CMS & ATLAS be correlated background mis-‐modeling ?




ATLAS (and CMS) have small Z+jets (green) contribu+on at low MT where excess is

1-‐jet bin




ATLAS (and CMS) have small Z+jets (green) contribu+on at low MT where excess is

1-‐jet bin

CDF has large Z+jets (yellow) contribu+on at low MT in same region •  And much smaller obar

1-‐jet bin

Tevatron cross-‐checks of excesses

•  Doesn’t mean Z+jets is underes+mated at CMS/ATLAS –  Since W+jets and Z+jets should be smaller backgrounds at LHC anyway

•  But it does mean that excesses at LHC or Tevatron could be due to different backgrounds –  Consistent excesses between Tevatron and LHC would constrain background fluctua+on interpreta+on

•  Tevatron also more sensi+ve from WH/ZH produc+on in high mass analysis, whereas LHC has more from VBF –  Consistent excesses between Tevatron and LHC would indicate SM Higgs boson rela+onship (ggH, WH/ZH, VBF)

•  Tevatron H➞WW important even when sensi+vity is eclipsed


What does Tevatron say about excesses ?



Actual Tevatron data

Signal injected at 115 GeV Signal injected at 125 GeV Signal injected at 135 GeV

Not quite consistent with 130 GeV injec+on

Tevatron perspec+ve from H➞bb


Let’s check Tevatron H➞bb

19

•  At 115-‐120 GeV –  Almost at 1*SM sensi+vity –  No excess seen –  Inconsistent with CMS & ATLAS

•  At 130-‐140 GeV –  2*SM – 3*SM sensi+vity –  No excess seen – would expect observed limit to be 1*SM high

B.Kilminster, Higgs Hun+ng

Signal injected at 115 GeV

)2Higgs Mass (GeV/c100 110 120 130 140 150

95%

CL

Lim

it/SM

1

10

210 1±Expected Limits

2±Expected Limits

2=115 GeV/cH

Expected with Injected M

)-1CDF II x 2 Preliminary (5.7 fb

Let’s check Tevatron H➞bb

20

•  At 115-‐120 GeV –  Almost at 1*SM sensi+vity –  No excess seen –  Inconsistent with CMS & ATLAS

•  At 130-‐140 GeV –  2*SM – 3*SM sensi+vity –  No excess seen – would expect observed limit to be 1*SM high


Signal injected at 115 GeV

)2Higgs Mass (GeV/c100 110 120 130 140 150

95%

CL

Lim

it/SM

1

10

210 1±Expected Limits

2±Expected Limits

2=115 GeV/cH

Expected with Injected M

)-1CDF II x 2 Preliminary (5.7 fb

Not consistent with 115 GeV injec+on

Higgs Boson Mass Msmst 19 Aug 2010 21

How well could we measure Higgs mass given a 3 Sigma excess ? -‐ Cross-‐sec+on is more sensi+ve to Higgs boson mass than resolu+on

Using resolu+on from LLR, median outcomes Resolu+on at 115 GeV: ±5 GeV Resolu+on at 135 GeV: ~±10 GeV

Assuming Cross Sec+on x Branching Frac+on Measurement Uncertainty is 2x Larger at the same Luminosity for low-‐mass than it is for high-‐mass searches

Tevatron prospects from H➞bb


Background modeling at 115 GeV

•  BKG modeling impressive over 7 orders of magnitude –  Dominated by b-‐tagged W+jets, Z+jets


Mjj bump •  Important for H➞bb searches at 115 GeV to have reliable modeling of main backgrounds : W+jets, Z+jets –  However …



25

147 ± 4 GeV 4.8 σ

Bump from subtrac+on of two falling distribu+ons



CDF is working toward understanding if this is caused by an unaccounted for systema+c uncertainty – and to quan+fy the effect on top and Higgs analyses

26

147 ± 4 GeV 4.8 σ

Bump from subtrac+on of two falling distribu+ons


Mjj bump tests •  Tests of varying background normaliza+ons and shapes with extreme varia+ons of known systema+c uncertain+es have been done




– it’s not them …



From Adam Mar+n (FNAL)

Cross-‐over in quark / gluon jet composi+on as func+on of Mjj around CDF bump

Best lead :

– it’s not them …

Quarks vs. gluons •  Cut on ra+o of highest PT / lowest PT sensi+ve to quark and gluon frac+ons

30

Standard (j1,j2 ET >30 GeV) J1 Et / j2 Et > 0.6 J1 Et / j2 Et > 0.8



31


4.8 σ 3.2 σ 3.6 σ



32


4.8 σ 3.2 σ 3.6 σ

No obvious magic bullet : decrease sta+s+cs ➞ decreased significance B.Kilminster, Higgs Hun+ng

Separa+ng quarks from gluons •  More recently, we have been doing studies with a quark-‐jet vs. gluon-‐jet separator


Test of quark gluon composi+on •  We test an orthogonal sample Z+jet to check jet energy

scale as a func+on of quark-‐jet vs. gluon-‐jet discriminator

34

“true“ jet PT determined from Z+jet balancing




35


Best agreement found when : •  Quark jet energy scale le{ alone •  Gluon jet energy scale shi{ed down in MC by 2 Sigma




36


Explains why in situ JES measurement from W➞qq in obar decays indicates JES is stable to 0.3 sigma

Also, explains why W+jets and Z+jets do not have mis-‐modeling when b-‐tag is applied (due to quark enhancement)


Best agreement found when : •  Quark jet energy scale le{ alone •  Gluon jet energy scale shi{ed down in MC by 2 Sigma

Applying the correc+on as a func+on of Q-‐G discriminator output

37

Gluon-‐enriched Quark-‐enriched

Includes 2σ JES down for gluons in MC


Effect on W+jj Mjj distribu+on •  CDF studies underway –  Hope to have a convincing answer soon whether gluon-‐jet JES 2 σ down solves problem of Mjj bump

•  D0 does not see Mjj bump •  Specula+on –  Perhaps D0 not as sensi+ve to quark vs. gluon JES differences •  Larger cone size 0.5 instead of 0.4 •  Different calorimeter

–  D0 has compensa+ng liquid argon calorimeter

–  CDF has lead & iron / sampling scin+lla+ng calorimeter


Good news is none of this would effect WH/ZH ➞ lv/ll/vv + bb searches

•  And they s+ll have excellent modeling


Future


Tevatron expecta+ons

•  Tevatron will deliver over 12 J-‐1 by Sept. 2011 –  10 J-‐1 acquired data by CDF and D0

•  Effec+vely means ~9 J-‐1 for use with all detector systems good (necessary WH, ZH b-‐tagged analyses)


Tevatron projec+ons 10 J-‐1 analyzed

3 σ : 115 GeV w/9 J-‐1

2.4 σ : 130 GeV w/10 J-‐1 42 B.Kilminster, Higgs Hun+ng

10 J-‐1

Are there poten+al improvements le{ ?


Some of these Improvements were made for summer

Es+mates of remaining : 35% WH 65% ZHllbb 12% ZHvvbb

from P5 report Oct. 2010

More importantly, can Tevatron achieve all projected improvements on +me-‐scale of Moriond 2012?

•  Are improvements slowing down due to reduced personnel ?





WH ➞ lvbb




WH ➞ lvbb ZH ➞ llbb

S+ll incorpora+ng new channels to improve sensi+vity at 115 GeV and 130 GeV

•  See Elisabeoa’s talk yesterday – New addi+ons for summer 2011 Tev combina+on •  oH ➞ met+jets •  oH ➞ leptons+jets

•  oH ➞ all-‐jets • WH ➞ lvττ

•  ZH ➞ llττ


Conclusions

•  Tevatron important at low mass 115 – 125 GeV –  Best current limits at 115 GeV – Unique window to Higgs of H➞bb –  Sensi+vity con+nues to improve

•  Tevatron important in 130-‐140 GeV region – H➞WW analyses sensi+ve to different signals and backgrounds than LHC •  LHC – Tevatron agreement paints a consistent picture

•  Tevatron will have 10 J-‐1 analyzed by spring/summer 2012 – Will have even more to say about 115 GeV and 130 GeV


49

Found that s/b(max) is the single most important determinant of our measurement sensi+vity.

Other things maoer, like the candidate mass resolu+on, mostly via their impact on this variable.

Signal cross sec+on x b.r. to bb is lower at higher mH, WW channels turning on without mrec info.

Guess – probably can’t get much beoer than 6%

Let’s call it ±11 GeV when we have all the excess from low-‐mass channels.


50

Leveraging our Rate Measurements to Measure the Higgs Boson Mass

Assuming SM cross sec+ons and branching frac+ons, measured rates are strong func+ons of mH. Example at mH=115 GeV, assuming +3 sigma excess, and a median outcome in both the bb,ττ channels and the WW channels:

Tau channels can contribute here, even with less precise mrec than the bb channels


Documents

Prospects)(perspec+ves))from) Tevatron)Higgs) fileTEV,)CMS,)ATLAS) Higgs boson mass (GeV/c2) 120 140 160 180 200 220 SM! / 95%! Limit on 1 10 Observed S CL Expected ± 1! S CL Expected