SUSY Higgs bosons at the LHC
a r X i v :0709.4408v 1 [h e p -p h ] 27 S e p 2007SUSY HIGGS BOSONS AT THE LHC G.WEIGLEIN IPPP,Department of Physics,University of Durham,South Road,Durham DH13LE,UK Recent results on MSSM Higgs physics at the LHC are reviewed.The dependence of the LHC discovery reach in the
b ˉbH/A,H/A →τ+τ?channel on the underlying SUSY scenario is analysed.This is done by combining the latest results for the prospective CMS experimen-tal sensitivities for an integrated luminosity of 30or 60fb ?1with state-of-the-art theoretical predictions of MSSM Higgs-boson properties.The results are interpreted in terms of the parameters governing the MSSM Higgs sector at lowest order,M A and tan β.While the higgsino mass parameter μhas a signi?cant impact on the prospective discovery reach (and correspondingly the “LHC wedge”region),it is found that the discovery reach is rather stable with respect to variations of other supersymmetri
c parameters.Within the discovery region a determination of the masses of the heavy neutral Higgs bosons with an accuracy of 1–4%seems feasible.It is furthermore shown that Higgs-boson production in central exclusive di?ractive channels can provide important information on the properties of the neutral MSSM Higgs bosons.1Introduction Signatures of an extende
d Higgs sector would provid
e unique evidence for physics beyond the Standard Model (SM).While models with an extended Higgs sector often give rise to a relatively light SM-like Higgs boson over a large part o
f their parameter space,detectin
g heavy states of an
extended Higgs sector and studying their properties will be of utmost importance for revealing the underlying physics.
2Dependence of the LHC discovery reach on the SUSY scenario
In Ref.1the reach of the CMS experiment with 30or 60fb ?1for the heavy neutral MSSM Higgs bosons has been analysed focusing on the channel b ˉbH/A,H/A →τ+τ?with the τ’s subsequently decaying to jets and/or leptons.The experimental analysis,yielding the number of events needed for a 5σdiscovery (depending on the mass of the Higgs boson)was performed with full CMS detector simulation and reconstruction for the ?nal states of di-τ-lepton decays 2.The events for the signal and background processes were generated using PYTHIA 3.The experimental analysis has been combined with predictions for the Higgs-boson masses,produc-tion processes and decay channels obtained with the code FeynHiggs 4,taking into account all relevant higher-order corrections as well as possible decays of the heavy Higgs bosons into su-persymmetric particles.The results have been interpreted in terms of the two parameters tan β,the ratio of the vacuum expectation values of the two Higgs doublets of the MSSM,and M A ,
the mass of the CP-odd Higgs boson.The variation of the discovery contours in the M A–tanβplane indicates the dependence of the“LHC wedge”region,i.e.the region in which only the light CP-even MSSM Higgs boson
can be detected at the LHC at the5σlevel,on the details of the supersymmetric theory.See Ref.5for previous analyses.
Figure1:Variation of the5σdiscovery contours obtained from the channel bˉbφ,φ→τ+τ?→jets in the m max
h benchmark scenario for di?erent values ofμ(left plot).The right plot shows the result in the case where no decays of the heavy Higgs bosons into supersymmetric particles are taken into account.
Fig.1shows the variation of the5σdiscovery contours obtained from the channel bˉbφ,φ→
τ+τ?→jets in the m max
h
benchmark scenario6for various values of the higgsino mass parameter μ.The parameterμenters via higher-order corrections a?ecting in particular the bottom Yukawa coupling as well as via its kinematic e?ect in Higgs decays into charginos and neutralinos.Both e?ects can be seen in Fig.1.While the left plot shows the full result,in the right plot no decays of the Higgs bosons into supersymmetric particles are taken into account,so that the right plot purely displays the e?ect of higher-order https://www.wendangku.net/doc/5016208424.html,parison of the two plots shows that in the region of large tanβ(corresponding to larger values of M A on the discovery contours)the dominant e?ect arises from higher-order corrections.For lower values of tanβ,on the other hand, the modi?cation of the Higgs branching ratio as a consequence of decays into supersymmetric particles yields the dominant e?ect on the5σdiscovery contours.The largest shift in the5σdiscovery contours amounts up to about?tanβ=10.The discovery contours have been shown to be rather stable with respect to the impact of other supersymmetric contributions1.
Figure2:The statistical precision of the Higgs-boson mass measurement achievable from the channel bˉbφ,φ→
τ+τ?→jets in the m max
h
benchmark scenario forμ=?200GeV(left)andμ=+200GeV(right)is shown
together with the5σdiscovery contour.
The prospective accuracy of the mass measurement of the heavy neutral MSSM Higgs bosons
in the channel bˉbH/A,H/A→τ+τ?is analysed in Fig.2.The statistical accuracy of the mass measurement has been evaluated via?Mφ√
the M A–tanβplane of the MSSM(using the m max
benchmark scenario6)for di?erent luminos-
h
ity scenarios.It is found that the CED Higgs-boson production channel can cover an interesting part of the MSSM parameter space at the5σlevel if the CED channel can be utilised at high in-stantaneous luminosity(which requires in particular to bring pile-up background under control). For an e?ective luminosity of600fb?1×2(see Ref.8)the discovery of a heavy CP-even Higgs boson with a mass of about140GeV will be possible for all values of tanβ.This is of particular interest in view of the“wedge region”left uncovered by the conventional search channels for heavy MSSM Higgs bosons(see above).In the high-tanβregion the discovery reach extends beyond M H=200GeV at the5-σlevel.If the Higgs bosons h and/or H have been detected in the conventional search channels,a lower statistical signi?cance may be su?cient for the CED production of h and H,corresponding to a larger coverage in the M A–tanβplane.The CED Higgs-boson production channel will provide in this case important information on the Higgs-boson properties and may even allow a direct measurement of the Higgs-boson width8.
Acknowledgments
The author gratefully acknowledges the collaboration with S.Gennai,S.Heinemeyer,A.Kali-nowski,V.A.Khoze,R.Kinnunen,S.Lehti,A.Nikitenko,M.G.Ryskin,W.J.Stirling and M.Tasevsky on the results presented in this paper.He also thanks the organisers of the42nd Rencontres de Moriond for the kind invitation and the pleasant atmosphere at the meeting.
References
1.S.Gennai,S.Heinemeyer,A.Kalinowski,R.Kinnunen,S.Lehti,A.Nikitenko and
G.Weiglein,arXiv:0704.0619[hep-ph],to appear in Eur.Phys.J.C.
2.CMS Physics Technical Design Report,Volume2.CERN/LHCC2006-021,see:
cmsdoc.cern.ch/cms/cpt/tdr/.
3.T.Sjostrand et al.,https://www.wendangku.net/doc/5016208424.html,mun.135(2001)238.
4.S.Heinemeyer,W.Hollik,G.Weiglein,https://www.wendangku.net/doc/5016208424.html,mun.124(2000)76;
hep-ph/0002213;Eur.Phys.J.C9(1999)343;G.Degrassi,S.Heinemeyer,W.Hollik, P.Slavich,G.Weiglein,Eur.Phys.J.C28(2003)133;M.Frank,T.Hahn,S.Heine-meyer,W.Hollik,H.Rzehak,G.Weiglein,JHEP02(2007)047;see:www.feynhiggs.de.
5.ATLAS Collaboration,Detector and Physics Performance Technical Design Report,
CERN/LHCC/99-15(1999);R.Kinnunen and A.Nikitenko,CMS note2003/006;
J.Thomas,ATL-PHYS-2003-003;D.Cavalli and D.Negri,ATL-PHYS-2003-009;S.Ab-dullin et al.,Eur.Phys.J.C39S2(2005)41;M.Carena,S.Heinemeyer,C.Wagner and
G.Weiglein,Eur.Phys.J.C45(2006)797.
6.M.Carena,S.Heinemeyer,C.Wagner and G.Weiglein,Eur.Phys.J.C26(2003)601.
7.V.A.Khoze,A.D.Martin and M.Ryskin,hep-ph/0006005;Eur.Phys.J.C19(2001)
477[Erratum-ibid.C20(2001)599].
8.S.Heinemeyer,V.A.Khoze,M.G.Ryskin,W.J.Stirling,M.Tasevsky and G.Weiglein,
arXiv:0708.3052[hep-ph].
9.A.Kaidalov,V.A.Khoze,A.D.Martin,M.Ryskin,Eur.Phys.J.C33(2004)261;
M.Boonekamp,J.Cammin,https://www.wendangku.net/doc/5016208424.html,vignac,R.Peschanski,C.Royon,Phys.Rev.D73 (2006)115011;J.Ellis,J.Lee,A.Pilaftsis,Phys.Rev.D70(2004)075010;Phys.Rev.
D71(2005)075007;V.A.Khoze,A.D.Martin,M.Ryskin,Eur.Phys.J.C34(2004) 327;B.Cox,F.Loebinger and A.Pilkington,arXiv:0709.3035[hep-ph].