In this presentation I will report on the search for the heavy boson H decaying to a pair of 125GeV SM-like Higgs bosons h using the ﬁnal state of two τ leptons and two b-jets and the search for a heavy boson A decaying to a SM-like Higgs boson h and a Z boson using the ﬁnal state of two τ leptons and two leptons ll (ee or μμ). The mass range considered in the analysis extends from mA/H l 250GeV up to mA/H l 350GeV. The analysis is performed on a dataset corresponding to an integrated luminosity of L = 19 .7fb−1 proton-proton collision data collected in 2012 by the CMS experiment at √s = 8TeV

Brivio, F.

Scientific Open-access Literature Archive and Repository

DOI 10.1393/ncc/i2017-17010-1Colloquia: IFAE 2016IL NUOVO CIMENTO 40 C (2017) 10Search for the H → hh → bbττ and A → Zh → llττ processes with8 TeV data in CMSF. Brivio for the CMS CollaborationINFN and Università di Milano-Bicocca - Milano, Italyreceived 17 October 2016Summary. — In this presentation I will report on the search for the heavy bosonH decaying to a pair of 125 GeV SM-like Higgs bosons h using the final state oftwo τ leptons and two b-jets and the search for a heavy boson A decaying to aSM-like Higgs boson h and a Z boson using the final state of two τ leptons andtwo leptons  (ee or μμ). The mass range considered in the analysis extends frommA/H  250 GeV up to mA/H  350 GeV. The analysis is performed on a datasetcorresponding to an integrated luminosity of L = 19.7 fb−1 proton-proton collisiondata collected in 2012 by the CMS experiment at√s = 8 TeV.1. – IntroductionAfter the discovery of the 125 GeV particle [1, 2], the observation of additional Higgsbosons at the LHC would provide direct evidence of physics beyond the standard model(SM). There are several types of models that require two Higgs doublets (2HDM) [3],one example is the minimal supersymmetric extension of the SM (MSSM) [4]. Thisleads to the prediction of five Higgs particles: one light and one heavy CP -even, h andH, one CP -odd A, and two charged H±. The masses and couplings of these bosons areinterrelated and, at tree level, can be described by two parameters, which are often chosento be the mass of the pseudoscalar boson mA and the ratio of the vacuum expectationvalues of the neutral components of the two Higgs doublets tanβ.In the mass region below 2mtop and at low values of tanβ, the decay mode of theheavy scalar H → hh and that of the pseudoscalar A → Zh can have sizeable branchingfractions. The choice of τ pair final state is driven by its quite clean signature, the largeexpected branching ratio and by the most recent results, which show strong evidence forthe 125 GeV Higgs boson coupling to fermions [5].This analysis [6] investigates the low tan β region which has not yet been excluded bythe direct or indirect searches for a heavy scalar or pseudoscalar Higgs boson.c© CERN on behalf of the CMS CollaborationCreative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0) 12 F. BRIVIO for the CMS COLLABORATION (GeV)Hm260 280 300 320 340) (pb)ττbb→hh→B(H×(ggH)σ95% CL limit on 0.20.40.60.81.01.21.4ObservedExpected Expectedσ 1± Expectedσ 2±CMS (8 TeV)-119.7 fbhτhτ+hτμ+hτeττbb→hh→H (GeV)Am250 300 350) (fb)ττLL→Zh→B(A×(ggA)σ95% CL limit on 05101520253035ObservedExpected Expectedσ 1± Expectedσ 2±CMS (8 TeV)-119.7 fbττllττll→Zh→AFig. 1. – Exclusion limits for H → hh → bbττ (left) and A → Zh → ττ (right).2. – Analysis strategyThe analysis strategy is similar for both processes. At first, the events are split indifferent channels, according to the decay of the τ pair. For the H → hh process, onlythree decay channels are considered: eτh, μτh and τhτh, where e/μ stand for the leptonicdecay of the τ , while τh represents hadronic decays. For the A → Zh process the decaychannels cosidered are eτh, μτh, τhτh and eμ.For the H → hh process, each event must satisfy the ττ selection criteria and containat least two jets with pT > 20GeV and |η| < 2.4. This requirement is necessary to furtherdivide events in three categories: 0-tag, 1-tag and 2-tag, depending on the number ofjets tagged as b-jets. The further categorisation of A → Zh events is based on the decayof the Z boson, either Z → ee or Z → μμ.Finally, some additional cuts are applied in order to reduce the background contri-butions. For H → hh, the signal-to-background ratio is greatly improved by selectingevents that are consistent with a mass of 125 GeV for both the di-jet (mbb) mass andthe di-tau mass (mττ ): the mass windows correspond to 70 < mbb < 150GeV and90 < mττ < 150GeV. For A → Zh, a requirement on LhT , which is the scalar sum of thevisible transverse momenta of the two τ candidates, is applied to lower the backgroundcontribution from ZZ production; moreover, the invariant mass of the two leptons comingfrom the Z decay must be between 60 and 120 GeV.The signal extraction is performed through a binned maximum-likelihood fit to the in-variant mass of the heavy bosons A/H. The mass mH is reconstructed using a kinematicfit, which takes as input the 4-momenta of the four bodies (ττbb) and the missing trans-verse energy and imposes kinematic constraints requiring mττ = mbb = mh = 125GeV.The mass of the A boson is estimated from the 4-vectors information of the interme-diate bosons: the Z boson is reconstructed from the ee/μμ momenta; the h boson isreconstructed through the SVFit algorithm [7].3. – ResultsIn neither search the invariant mass spectra show any evidence of a signal, thus modelindependent upper limits at 95% confidence level (CL) are set on the parameter of interestσ × BR for the H → hh → bbττ and A → Zh → ττ processes, fig. 1.SEARCH FOR THE H → hh → bbττ AND A → Zh → llττ PROCESSES WITH 8TeV DATA IN CMS 3 (GeV)Am250 300 350βtan1.01.52.02.53.03.54.095% CL Excluded:Observed  Expectedσ 1±Expected  Expectedσ 2±3 GeV± 125≠hMSSMm scenarioβMSSM low tanCMS (8 TeV)-119.7 fbττll→Zh→ + Aττbb→hh→H)α-βcos(-1.0 -0.5 0.0 0.5 1.0βtan1234567891095% CL Excluded:Observed  Expectedσ 1±Expected  Expectedσ 2± = 300 GeVH = mA2HDM type-II, mCMS  (8 TeV)-119.7 fbττll→Zh→+Aττbb→hh→HFig. 2. – Interpretation of the exclusion limits in the low tan β MSSM scenario (left) and in aType-II 2HDM model (right).Exclusion limits are determined using the CLs method [8], where systematic uncer-tainties are taken into account as nuisance parameters, profiled in the fit procedure.The observed limits on cross section times branching fraction can be interpreted inthe MSSM and 2HDM frameworks, as shown in fig. 2. Especially, this analysis provesto be powerul in the investigation and exclusion of low tanβ regions in the mass rangebetween 250 and 350 GeV.REFERENCES[1] CMS Collaboration, Phys. Lett. B, 716 (2012) 30, doi: 10.1016/j.physletb.2012.08.021.[2] ATLAS Collaboration, Phys. Lett. B, 716 (2012) 1, doi: 10.1016/j.physletb.2012.08.020.[3] Branco G. C. et al., Phys. Rep., 516 (2012) 1, doi: 10.1016/j.physrep.2012.02.002.[4] Bagnaschi E. et al., Benchmark scenarios for low tan β in the MSSM, Technical ReportLHCHXSWG-2015-002, CERN, Geneva (2015).[5] CMS Collaboration, Nat. Phys., 10 (2014) 557, doi: 10.1038/nphys3005.[6] CMS Collaboration, Phys. Lett. B, 755 (2016) 217, doi: 10.1016/j.physletb.2016.01.056.[7] Bianchini L., Conway J., Friis E. K. and Veelken C., J. Phys. Conf. Ser., 513 (2014)022035, doi: 10.1088/1742-6596/513/2/022035.[8] Read A. L., J. Phys. G, 28 (2002) 2693, doi: 10.1088/0954-3899/28/10/313.

Search for the H → hh → bbττ and A → Zh→ llττ processes with 8TeV data in CMS

In this presentation I will report on the search for the heavy boson H decaying to a pair of 125 GeV SM-like Higgs bosons $h$ using the final state of two $\tau$ leptons and two $b$-jets and the search for a heavy boson A decaying to a SM-like Higgs  boson $h$ and a $Z$ boson using the final state of two $\tau$ leptons and two leptons $\ell\ell$ ($ee$ or $\mu\mu$). The mass range considered in the analysis extends from $m_{A/H} \simeq 250$ GeV  up to $m_{A/H} \simeq 350$ GeV. The analysis is performed on a dataset corresponding to an integrated luminosity $\mathcal{L} = 19.7\ fb^{-1} $ of proton-proton collision data collected in 2012 by the CMS experiment at $\sqrt{s} = 8$ TeV

Brivio, Francesco

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Search for the $H\to hh\to bb\tau\tau$ and $A\to Zh\to ll\tau\tau$ processes with 8 TeV data in CMS.

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Search for the H → hh → bbττ and A → Zh→ llττ processes with 8TeV data in CMS

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