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CMSPublic Web>HtoZgMoriondDocument>Hig13006TWiki (2013-03-06, JimOlsen) (raw view)

---+!! Search for a Light Higgs boson in the Z boson plus a Photon Decay Channel


This is a condensed description with plots for the analysis [[http://cms.cern.ch/iCMS/jsp/analysis/admin/analysismanagement.jsp?ancode=HIG-13-006][CMS-HIG-13-006]]

%TOC%

---+Abstract

A search for a Higgs boson decaying into a Z boson and a photon is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from proton-proton collisions at a centre-of-mass energy of 7 and 8 TeV, corresponding
to an integrated luminosity of 5.0 and 19.6 fb^-1, respectively. Limits are set on
the cross section of a standard model Higgs boson decaying to opposite-sign electron
or muon pairs and a photon. The expected exclusion limits at 95% confidence level
are between 6 and 19 times the standard model cross section in the mass range of 120
and 150 GeV, and the observed limits are between about 3 and 31 times the standard
model cross section.


---+Main result
A search has been made for a Higgs boson decaying into a Z boson plus a photon in the CMS detector
at a centre-of-mass energy of 7 and 8 TeV, and the data sample corresponds to 24.6 fb-1 of integrated luminosity.
Events are classified in four categories according to topology of the leptons
and the photon,  and the photon shower shape. The main backgrounds (pp to Zg and Drell-Yan+jets)
are estimated with data-driven techniques.

The search discussed here is performed over the mass range 120--150 GeV.  No excess been found in the current 
data sample and the first limits on the Higgs production cross-section times the H to Zg branching fraction at the LHC have been derived.
The upper cross-section limits for the  Higgs production times branching fraction decays into Z plus photon are about an order of 
magnitude larger than the standard model  expectation for mH = 125 GeV. 

---+ PAS Figures:
| *Figure* | *Label* | *Description* | 
|<img src="%ATTACHURLPATH%/combinedData_All_2GeV.png" alt="combinedData_All_2GeV.png" width="300" height="" /> |[[%ATTACHURL%/combinedData_All_2GeV.png][png]], [[%ATTACHURL%/combinedData_All_2GeV4.pdf][pdf]] | mllg spectrum in the electron and the muon channels for the 7 and 8 !TeV data combined. Also shown is the expected signal due to a 125 !GeV standard model Higgs scale by 100 and the sum of the individual fits made to the data for each channel and event class at 7 and 8 !TeV.|
|<img src="%ATTACHURLPATH%/Pas2GevSigRegion_el2011CAT14.png" alt="Pas2GevSigRegion_el2011CAT14.png" width="300" height="" /> | [[%ATTACHURL%/Pas2GevSigRegion_el2011CAT14.png][png]], [[%ATTACHURL%/Pas2GevSigRegion_el2011CAT14.pdf][pdf]] | Background model fit to the m_eeg distribution for Event classes 1 and 2 for the year 2011|
|<img src="%ATTACHURLPATH%/Pas2GevSigRegion_el2011CAT23.png" alt="Pas2GevSigRegion_el2011CAT23.png" width="300" height="" /> | [[%ATTACHURL%/Pas2GevSigRegion_el2011CAT23.png][png]], [[%ATTACHURL%/Pas2GevSigRegion_el2011CAT23.pdf][pdf]] | Background model fit to the m_eeg distribution for Event classes 3 and 4 for the year 2011|
|<img src="%ATTACHURLPATH%/Pas2GevSigRegion_el2012CAT14.png" alt="Pas2GevSigRegion_el2012CAT14.png" width="300" height="" /> | [[%ATTACHURL%/Pas2GevSigRegion_el2012CAT14.png][png]], [[%ATTACHURL%/Pas2GevSigRegion_el2012CAT14.pdf][pdf]] | Background model fit to the m_eeg distribution for Event classes 1 and 2 for the year 2012 |
|<img src="%ATTACHURLPATH%/Pas2GevSigRegion_el2012CAT23.png" alt="Pas2GevSigRegion_el2012CAT23.png" width="300" height="" /> | [[%ATTACHURL%/Pas2GevSigRegion_el2012CAT23.png][png]], [[%ATTACHURL%/Pas2GevSigRegion_el2012CAT23.pdf][pdf]] | Background model fit to the m_eeg distribution for Event classes 3 and 4 for the year 2012 |
|<img src="%ATTACHURLPATH%/Pas2GevSigRegion_mu2011CAT14.png" alt="Pas2GevSigRegion_mu2011CAT14.png" width="300" height="" /> | [[%ATTACHURL%/Pas2GevSigRegion_mu2011CAT14.png][png]], [[%ATTACHURL%/Pas2GevSigRegion_mu2011CAT14.pdf][pdf]] | Background model fit to the m_mumug distribution for Event classes 1 and 2 for the year 2011|
|<img src="%ATTACHURLPATH%/Pas2GevSigRegion_mu2011CAT23.png" alt="Pas2GevSigRegion_mu2011CAT23.png" width="300" height="" /> | [[%ATTACHURL%/Pas2GevSigRegion_mu2011CAT23.png][png]], [[%ATTACHURL%/Pas2GevSigRegion_mu2011CAT23.pdf][pdf]] | Background model fit to the m_mumug distribution for Event classes 3 and 4 for the year 2011|
|<img src="%ATTACHURLPATH%/Pas2GevSigRegion_mu2012CAT14.png" alt="Pas2GevSigRegion_mu2012CAT14.png" width="300" height="" /> | [[%ATTACHURL%/Pas2GevSigRegion_mu2012CAT14.png][png]], [[%ATTACHURL%/Pas2GevSigRegion_mu2012CAT14.pdf][pdf]] | Background model fit to the m_mumug distribution for Event classes 1 and 2 for the year 2012 |
|<img src="%ATTACHURLPATH%/Pas2GevSigRegion_mu2012CAT23.png" alt="Pas2GevSigRegion_mu2012CAT23.png" width="300" height="" /> | [[%ATTACHURL%/Pas2GevSigRegion_mu2012CAT23.png][png]], [[%ATTACHURL%/Pas2GevSigRegion_mu2012CAT23.pdf][pdf]] | Background model fit to the m_mumug distribution for Event classes 3 and 4 for the year 2012 |
| <img src="%ATTACHURLPATH%/limitplot_AnalyticPDF-color.png" alt="limitplot_AnalyticPDF-color.png" width="300" height="" /> | [[%ATTACHURL%/limitplot_AnalyticPDF-color.png][png]], [[%ATTACHURL%/limitplot_AnalyticPDF-color.pdf][pdf]] | Exclusion limit on the cross section of a SM Higgs boson decaying into Z-boson and a photon as a function of the boson mass based on 5.0 fb-1 at of data taken at 7 !TeV and 19.6 fb-1 at 8 !TeV. |

 
---+ PAS Tables:

| *Table* | *Label* | *Description* | 
| <img src="%ATTACHURLPATH%/Table1.png" alt="Table1.png" width="300" height="" /> | [[%ATTACHURL%/Table1.png][png]] | Luminosity and observed data yields used in the analysis. Expected signal yields are for a 125 !GeV SM Higgs boson. |
| <img src="%ATTACHURLPATH%/Table2.png" alt="Table2.png" width="300" height="" /> | [[%ATTACHURL%/Table2.png][png]] | Definition of event classes. | 
| <img src="%ATTACHURLPATH%/Table3.png" alt="Table3.png" width="300" height="" /> | [[%ATTACHURL%/Table3.png][png]] | Systematic uncertainties. | 



---+ Additional Figures:
| *Figure* | *Label* | *Description* | 
|<img src="%ATTACHURLPATH%/combinedData_All_2GeV_Weighted.png" alt="combinedData_All_2GeV_Weighted.png" width="300" height="" /> |[[%ATTACHURL%/combinedData_All_2GeV_Weighted.png][png]], [[%ATTACHURL%/combinedData_All_2GeV_Weighted.pdf][pdf]] | mllg spectrum in the electron and the muon channels for the 7 and 8 !TeV data combined and weighted by the significance [S/(S+B)] expected at 125 GeV. Also shown is the expected signal due to a 125 !GeV standard model Higgs scale by 100 and the sum of the individual fits made to the data for each channel and event class at 7 and 8 !TeV. The combined reweighted distributions are then normalized to the original data yield.|
| <img src="%ATTACHURLPATH%/limitplot_AnalyticPDF-only.png" alt="limitplot_AnalyticPDF-only.png" width="300" height="" /> | [[%ATTACHURL%/limitplot_AnalyticPDF-only.png][png]], [[%ATTACHURL%/limitplot_AnalyticPDF-only.pdf][pdf]] | Exclusion limit on the cross section of a SM Higgs boson decaying into Z-boson and a photon as a function of the boson mass based on 5.0 fb-1 at of data taken at 7 !TeV and 19.6 fb-1 at 8 !TeV and the expect exclusion limit from our previous analysis (HIG-12-049) based on 5.0 fb-1 at of data taken at 7 !TeV and 5.0 fb-1 at 8 !TeV.  *** Alternative colors for the one and two sigma band -- used in HIG-12-049. *** |
| <img src="%ATTACHURLPATH%/limitplot_AnalyticPDF-4.png" alt="limitplot_AnalyticPDF-4.png" width="300" height="" /> | [[%ATTACHURL%/limitplot_AnalyticPDF-4.png][png]], [[%ATTACHURL%/limitplot_AnalyticPDF-4.pdf][pdf]] | Exclusion limit on the cross section of a SM Higgs boson decaying into Z-boson and a photon as a function of the boson mass based on 5.0 fb-1 at of data taken at 7 !TeV and 19.6 fb-1 at 8 !TeV and the expect exclusion limit from our previous analysis (HIG-12-049) based on 5.0 fb-1 at of data taken at 7 !TeV and 5.0 fb-1 at 8 !TeV.  *** Alternative colors for the one and two sigma band. *** |
| <img src="%ATTACHURLPATH%/limitplot_AnalyticPDF_InCludingOld-color.png" alt="limitplot_AnalyticPDF_InCludingOld-color.png" width="300" height="" /> | [[%ATTACHURL%/limitplot_AnalyticPDF_InCludingOld-color.png][png]], [[%ATTACHURL%/limitplot_AnalyticPDF_InCludingOld-color.pdf][pdf]] | Exclusion limit on the cross section of a SM Higgs boson decaying into Z-boson and a photon as a function of the boson mass based on 5.0 fb-1 at of data taken at 7 !TeV and 19.6 fb-1 at 8 !TeV and the expect exclusion limit from our previous analysis (HIG-12-049) based on 5.0 fb-1 at of data taken at 7 !TeV and 5.0 fb-1 at 8 !TeV. |

| <img src="%ATTACHURLPATH%/pValueplot.png" alt="pValueplot.png" width="300" height="" /> | [[%ATTACHURL%/pValueplot.png][png]], [[%ATTACHURL%/pValueplot.pdf][pdf]] | The observed local p-value p0 as a function of the SM Higgs boson mass in the range 120–150 GeV. |

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
pdf	pValueplot.pdf	r1	manage	19.1 K	2013-02-28 - 15:15	MaydaVelasco
pdf	pValueplot_BkgModelPolOnly.pdf	r1	manage	19.1 K	2013-02-27 - 23:41	MaydaVelasco
pdf	limitplot_AnalyticPDF-color.pdf	r1	manage	21.4 K	2013-03-05 - 02:42	MaydaVelasco
pdf	limitplot_AnalyticPDF-only.pdf	r1	manage	21.4 K	2013-02-27 - 23:05	MaydaVelasco
pdf	limitplot_AnalyticPDF-4.pdf	r1	manage	21.8 K	2013-02-27 - 23:05	MaydaVelasco
pdf	limitplot_AnalyticPDF_InCludingOld-color.pdf	r1	manage	21.8 K	2013-03-05 - 02:42	MaydaVelasco
pdf	combinedData_All_2GeV.pdf	r1	manage	28.7 K	2013-02-27 - 23:24	MaydaVelasco
pdf	combinedData_All_2GeV_Weighted.pdf	r1	manage	28.9 K	2013-02-27 - 23:24	MaydaVelasco
pdf	Pas2GevSigRegion_el2011CAT14.pdf	r2 r1	manage	31.1 K	2013-03-03 - 13:41	MaydaVelasco
pdf	Pas2GevSigRegion_mu2011CAT14.pdf	r2 r1	manage	31.1 K	2013-03-03 - 13:48	MaydaVelasco
pdf	Pas2GevSigRegion_el2012CAT14.pdf	r1	manage	31.3 K	2013-02-27 - 23:13	MaydaVelasco
pdf	Pas2GevSigRegion_mu2012CAT14.pdf	r1	manage	31.6 K	2013-02-27 - 23:15	MaydaVelasco
pdf	Pas2GevSigRegion_mu2011CAT23.pdf	r2 r1	manage	36.2 K	2013-03-03 - 13:48	MaydaVelasco
pdf	Pas2GevSigRegion_el2011CAT23.pdf	r1	manage	37.2 K	2013-02-27 - 23:13	MaydaVelasco
pdf	Pas2GevSigRegion_mu2012CAT23.pdf	r2 r1	manage	38.3 K	2013-03-03 - 13:50	MaydaVelasco
pdf	Pas2GevSigRegion_el2012CAT23.pdf	r1	manage	38.9 K	2013-02-27 - 23:13	MaydaVelasco
png	Pas2GevSigRegion_el2011CAT14.png	r2 r1	manage	53.5 K	2013-03-03 - 13:43	MaydaVelasco
png	Pas2GevSigRegion_mu2011CAT23.png	r2 r1	manage	53.5 K	2013-03-03 - 13:48	MaydaVelasco
png	Pas2GevSigRegion_el2011CAT23.png	r1	manage	54.5 K	2013-02-27 - 23:13	MaydaVelasco
png	Pas2GevSigRegion_mu2011CAT14.png	r2 r1	manage	55.9 K	2013-03-03 - 13:48	MaydaVelasco
png	Pas2GevSigRegion_el2012CAT14.png	r1	manage	56.5 K	2013-02-27 - 23:13	MaydaVelasco
png	Pas2GevSigRegion_mu2012CAT14.png	r1	manage	58.6 K	2013-02-27 - 23:15	MaydaVelasco
png	Table1.png	r1	manage	59.4 K	2013-02-27 - 22:58	MaydaVelasco
png	Pas2GevSigRegion_mu2012CAT23.png	r2 r1	manage	61.0 K	2013-03-03 - 13:50	MaydaVelasco
png	Pas2GevSigRegion_el2012CAT23.png	r1	manage	62.7 K	2013-02-27 - 23:13	MaydaVelasco
png	pValueplot.png	r1	manage	105.0 K	2013-02-28 - 15:15	MaydaVelasco
png	pValueplot_BkgModelPolOnly.png	r1	manage	105.4 K	2013-02-27 - 23:41	MaydaVelasco
png	limitplot_AnalyticPDF-color.png	r1	manage	141.2 K	2013-03-05 - 02:42	MaydaVelasco
png	limitplot_AnalyticPDF-only.png	r1	manage	143.8 K	2013-02-27 - 23:05	MaydaVelasco
png	combinedData_All_2GeV.png	r1	manage	144.3 K	2013-02-27 - 23:24	MaydaVelasco
png	combinedData_All_2GeV_Weighted.png	r1	manage	149.2 K	2013-02-27 - 23:24	MaydaVelasco
png	limitplot_AnalyticPDF_InCludingOld-color.png	r1	manage	154.1 K	2013-03-05 - 02:42	MaydaVelasco
png	limitplot_AnalyticPDF-4.png	r1	manage	157.3 K	2013-02-27 - 23:05	MaydaVelasco
png	Table3.png	r1	manage	196.7 K	2013-02-27 - 22:58	MaydaVelasco
png	Table2.png	r1	manage	234.8 K	2013-02-27 - 22:58	MaydaVelasco

Topic revision: r6 - 2013-03-06 - JimOlsen

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