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---+Search for charged Higgs boson in ttbar in pp collisions at %$\sqrt{s}=7$%TeV

---++ Main Results 
The large top quark production cross section at the Large Hadron Collider offers the opportunity to search for the 
charged Higgs boson as the decay %$t\rightarrow H^+b\rightarrow \tau^+\nu b$%  can be large in extensions of the standard model, 
if the mass is lighter than the top quark mass. A direct search for the charged Higgs boson in events with one lepton (electron or muon), at least two jets, 
missing transverse energy, and one hadronically decaying tau lepton has been performed in 36 pb%$^{-1}$% of data collected in proton-proton collisions at %$\sqrt{s}=7$% TeV.
We do not find a signal in our search and derive an upper limit on the branching ratio %$BR(t\rightarrow H^+b)\simeq 0.25-0.28$%
for masses between 80 and 140GeV/%$c^2$%, when assuming %$BR(H^+\rightarrow \tau^+\nu)=1$%.

---++ Figures and Tables from [[http://cms.cern.ch/iCMS/analysisadmin/cadi?ancode=HIG-11-002][CMS-HIG-11-002]]

| *Figure* | *Label* | *Description* |
| [[%ATTACHURLPATH%/leptonjets_pf_jetmultiplicity_init_noratio.png][<img src="%ATTACHURLPATH%/leptonjets_pf_jetmultiplicity_init_noratio.png" width=300/>]] | Figure 2, left | Jet multiplicity distribution (%$p_T>30$% GeV/c, %$\eta<2.4$%) after requiring one isolated lepton. | 
| [[%ATTACHURLPATH%/leptonjets_pf_met_2j_syst.png][<img src="%ATTACHURLPATH%/leptonjets_pf_met_2j_syst.png" width=300/>]] | Figure 2, right | MET distribution for events with one isolated lepton and at least two jets; the hatched area shows the uncertainty. The last bin includes the events in the overflow bins. | 
| [[%ATTACHURLPATH%/hps0_yields.png][<img src="%ATTACHURLPATH%/hps0_yields.png" width=300/>]] | Figure 3 | Data and MC event yields at various levels of the selection. |
| [[%ATTACHURLPATH%/pf_wplusjets_pt.png][<img src="%ATTACHURLPATH%/pf_wplusjets_pt.png" width=300/>]] | Figure 4, left | Inclusive jet %$p_T$% distribution for %$\ell+\geq3$% jet events after the MET cut, and with at least two jets with %$p_T>$% 30 GeV/c and at least one jet with %$p_T>$%20 GeV/c. Entries in the last bin include the overflows. |
| [[%ATTACHURLPATH%/hps_Loose_eff_vs_Pt_diff_data.png][<img src="%ATTACHURLPATH%/hps_Loose_eff_vs_Pt_diff_data.png" width=300/>]] | Figure 4, right | Probability that a jet fakes a %$\tau$%-jet as obtained from the QCD multi-jet events taken during runs with and without pileup. |
| [[%ATTACHURLPATH%/EventDist_hpsLoose.png][<img src="%ATTACHURLPATH%/EventDist_hpsLoose.png" width=300/>]] | Figure 5 | Expected number of %$t \bar{t}$% events after the final event selection as a function of the branching ratio %$BR(t\rightarrow  H^{+}b)$% for %$M_{H ^{+}}$%=120 GeV/%$c^2$%. Expectations are also shown separately for WH, HH and %$t \bar{t} \rightarrow W^+bW^-\bar{b}$% (WW) contributions. |
| [[%ATTACHURLPATH%/EventDist_brLimit_hps0_os.png][<img src="%ATTACHURLPATH%/EventDist_brLimit_hps0_os.png" width=300/>]] | Figure 6 | The relation between %$N_{up}$% and the upper limit on %$BR(t\rightarrow  H^{+}b)$% for the observed and the expected limit with %$\pm 1\sigma$% error band shown in yellow color for %$M_{H^{\pm}}$%=120~GeV/c%$^2$%, where %$BR(H^{+} \rightarrow \tau \nu)=1$% is assumed. |
| [[%ATTACHURLPATH%/limit_hps_loose_upto140GeV.png][<img src="%ATTACHURLPATH%/limit_hps_loose_upto140GeV.png" width=300/>]] | Figure 7 | Upper limit on %$BR(t\rightarrow H^{+}b)$% assuming %$BR(H^{+} \rightarrow \tau \nu)=1$% as a function of %$M_{H^{+}}$%. The yellow band shows the %$\pm 1\sigma$% band around the expected limit. |
| [[%ATTACHURLPATH%/Table1.png][<img src="%ATTACHURLPATH%/Table1.png" width=300/>]] | Table 1 | The systematics uncertainties for backgrounds, signal events from %$t \bar{t} \rightarrow H^{\pm}bH^{\mp}\bar{b}$% (HH) and %$t \bar{t} \rightarrow W^{\pm}bH^{\mp}\bar{b}$% (WH) processes at %$M_{H ^{\pm}}$=120 GeV/%$c^2$%. These systematic uncertainties are given as the input for the exclusion limit calculation. |
| [[%ATTACHURLPATH%/Table2.png][<img src="%ATTACHURLPATH%/Table2.png" width=300/>]] | Table 2 | Number of expected events for the backgrounds, signal events from %$t \bar{t} \rightarrow H^{\pm}bH^{\mp}\bar{b}$% (HH) and %$t \bar{t} \rightarrow W^{\pm}bH^{\mp}\bar{b}$% (WH) processes at %$M_{H ^{\pm}}$%=120 GeV/%$c^2$%, and the number of observed events after the final event selection. Statistical and systematic uncertainties are shown. The statistical uncertainties are due to MC statistics, while for the $\tau$-fakes the statistical uncertainties are due to the fake rate in the data. Of the 40 events found in the data, 16~(24) events are in the %$e\tau$% (%$\mu\tau$%) final state, which is expected as the electron efficiency is lower than the muon efficiency. |

-- Main.MicheleGallinaro - 14-Mar-2011

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
png	EventDist_brLimit_hps0_os.png	r1	manage	19.0 K	2011-03-14 - 17:29	MicheleGallinaro
png	EventDist_hpsLoose.png	r1	manage	19.3 K	2011-03-14 - 17:28	MicheleGallinaro
png	Table1.png	r1	manage	55.1 K	2011-03-14 - 18:09	MicheleGallinaro
png	Table2.png	r1	manage	114.9 K	2011-03-14 - 18:11	MicheleGallinaro
png	hps0_yields.png	r1	manage	14.2 K	2011-03-14 - 17:17	MicheleGallinaro
png	hps_Loose_eff_vs_Pt_diff_data.png	r1	manage	11.8 K	2011-03-14 - 17:26	MicheleGallinaro
png	leptonjets_pf_jetmultiplicity_init_noratio.png	r1	manage	13.5 K	2011-03-14 - 17:08	MicheleGallinaro
png	leptonjets_pf_met_2j_syst.png	r1	manage	20.8 K	2011-03-14 - 17:16	MicheleGallinaro
png	limit_hps_loose_upto140GeV.png	r1	manage	16.0 K	2011-03-14 - 17:43	MicheleGallinaro
png	pf_wplusjets_pt.png	r1	manage	19.5 K	2011-03-14 - 17:18	MicheleGallinaro
tex	summary-tab-tau-3-syst.tex	r1	manage	1.1 K	2011-03-14 - 17:46	MicheleGallinaro
tex	summary-tab-tau-3.tex	r1	manage	0.9 K	2011-03-14 - 17:27	MicheleGallinaro

Topic revision: r1 - 2011-03-14 - MicheleGallinaro

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