LHC Potential for the Higgs Boson Discovery

The searches for the Higgs boson(s) of the Standard Model and its Minimal Supersymmetric extension with the CMS and ATLAS detectors at the LHC are discussed. Presented at Hadron Structure 2004, Smolenice Castle, Slovakia


Introduction
The CERN LHC collider is expected to start functioning within the next few years allowing the direct search for Higgs bosons in the full mass range.In this report, the LHC potential for the Higgs boson discovery is discussed in the framework of the Standard Model (SM) and its Minimal Supersymmetric extension (MSSM).In the SM Higgs mechanism, the Higgs boson mass m H is a free parameter bounded from below to m H > 114. 4 GeV/c 2 by the LEP measurements [1].The fits to the electroweak data favour a light Higgs boson with a central value of m H = 114 +69 −45 GeV/c 2 and a 95% CL upper limit of 260 GeV/c 2 [2].The MSSM contains five Higgs bosons: the lighter scalar h, the heavier scalar H, the pseudoscalar A and the two charged bosons H ± .The MSSM parameter space is in general presented as a function of the pseudoscalar mass m A and the ratio tanβ of the vacuum expectation values of the two Higgs doublets.In most of the LHC studies, the remaining SUSY parameters are fixed to the values used in the LEP studies [3]: M 2 = 200 GeV/c 2 , µ = − 200 GeV/c 2 , M g = 800 GeV/c 2 , M q, ˜ = 1 TeV/c 2 .For the no-stop-mixing scenario A t is set to zero and for the maximal mixing scenario A t is set to 2450 GeV/c 2 .The LEP measurements yield lower bounds of 91.0 and 91.9 GeV/c 2 for the masses of the h and A bosons in the MSSM [4].The excluded tanβ regions are 0.5< tanβ < 2.4 for the maximal m h scenario and 0.7< tanβ < 10.5 for the no-stop-mixing scenario [4].
At tree level the h(H) mass is bound to be below(above) the Z boson mass but the radiative corrections, proportional to m 4  top , bring the upper (lower) bound to a significantly larger value.The one loop and dominant two loop calculations, with the SUSY parameters listed above and with a top quark mass of 175 GeV/c 2 , predict an upper bound of 127 GeV/c 2 with maximal stop quark mixing [5].This upper bound increases to 132 GeV/c 2 with the recent value of the top quark mass (178.3GeV/c 2 ) from the Tevatron [6].This change in the top mass affects the LHC expectations mainly through the maximum value of m h , with renewed interest in the small tanβ region.This report summarizes the CMS and ATLAS searches for the SM and MSSM Higgs bosons.The Higgs boson production and decay are discussed in Section 2. The CMS and ATLAS detectors are briefly presented in Section 3. Sections 4 and 5 discuss and summarize the discovery potential for the SM and MSSM Higgs bosons.Specific SUSY searches are discussed in Section 6, measurements of Higgs boson properties in Section 7 and conclusions are given in Section 8.

Higgs boson production and decay
In the SM, the Higgs boson production is dominated by the gluon-gluon fusion, gg → H, over the full mass range 100 < ∼ m H < ∼ 1 TeV/c 2 .The cross section is about 10 pb around m H ∼ 200 GeV/c 2 .The QCD corrections for the gg → H process are large, with a next-to-leading (NLO) k factor ranging from 1.5 to 1.8 [7].In the CMS studies, k factors are used for the channels (signal and the corresponding backgrounds) dominated by the gg → H process, like the inclusive H → γγ channel.The other production processes, qq → qqH, qq → HW, qq → HZ, gg/qq → ttH and gg/qq → bbH have cross sections lower by one order of magnitude or more but often give possibilities for more efficient background suppression than in the gluon-gluon fusion process.
In the MSSM, the lighter scalar h is SM-like for m A > m max h (decoupling region), with production cross sections and decay partial widths close to those of the SM Higgs boson.At large tanβ, the couplings of the heavy neutral Higgs bosons to the electroweak gauge bosons are strongly suppressed, while those to the down-type fermions are enhanced with tanβ.The production of the heavy neutral MSSM Higgs bosons H and A proceeds mainly through gg → H/A and gg/qq → bbH/A.At large tanβ, the bbH/A associated production dominates and is about 90% of the total rate for tanβ > ∼ 10 and m A > ∼ 300 GeV/c 2 .If the charged Higgs bosons are light, m H ± < m top , they are produced in tt events through the t → H ± b decay.Heavier (m H ± ≥ m t ) charged Higgs bosons are mainly produced in the gg → tbH ± process.When the associated b jet is not detected, the gb → tH ± process with integration over the final state b quark can be used [8].
The branching fractions for the SM-like Higgs boson are shown in Fig. 1 as a function of the Higgs boson mass [9].For Higgs boson masses below 130 GeV/c 2 , the H → bb decay channel dominates while the branching fraction for H → γγ is only ∼ 1.5×10 −3 for m H < ∼ 150 GeV/c 2 .For larger m H , the decays are dominated by the H → WW * /WW and H → ZZ * /ZZ channels.
Figure 2 shows the branching fractions for the MSSM Higgs boson H and A for tanβ = 40.The branching fraction to τ + τ − is about 10% and that to µ + µ − about 3 × 10 −4 .At small tanβ, the branching fractions to gauginos, when kinematically allowed, dominate and suppress the branching fractions to SM particles.The branching fraction to tt, however, reaches ∼ 70% at large m A .The thresholds for decays to gauginos are sensitive to the SUSY parameters, in particular to |µ| and M 2 , through the gaugino masses.Light charged Higgs bosons (m H ± < m top )  decay to τ ν τ with an almost 100% branching fraction.For m H ± > ∼ 200 GeV/c 2 the H ± → tb decay dominates at large tanβ while the H ± → τ ν τ branching fraction decreases and is about 10% for m H ± > ∼ 400 GeV/c 2 .The decay branching fractions to gauginos can reach ∼ 10% at large tanβ and ∼ 30% at small tanβ, with the SUSY parameters listed in the introduction.

CMS and ATLAS Detectors
Detailed descriptions of the CMS and ATLAS detectors can be found in Refs.[10][11][12][13].In CMS, the calorimeters are located between the tracker and the superconducting coil.Other features of the CMS detector are a strong 4T axial magnetic field, a multilayer muon system in the return yoke and a scintillating crystal electromagnetic calorimeter.Figure 3 shows an overview of the CMS detector.The tracker, placed closest to the beam pipe, is made of fine-grained micro-strip and pixel detectors.The electromagnetic calorimeter is composed of about 80000 PbWO 4 crystals, with a single crystal front face of ∆η × ∆φ = 0.0174×0.0174,covering the rapidity range up to |η| < 3. The sampling hadron calorimeter extends up to |η| = 3, and consists of 4 mm thick plastic scintillator tiles inserted between brass absorber plates.The outer hadron calorimeter is located in the central region of the detector, |η| < 1.305, outside the solenoid in the barrel return yoke to measure the late shower development.To extend the hermeticity of the hadron calorimeter up to |η| = 5.191, a separate forward calorimeter is placed at a distance of 11 m from the interaction point.The muon system [12] contains four stations of muon chambers (up to |η| < 2.4) and consists of drift tubes in the barrel region, cathode strip chambers in the endcap regions and resistive plate chambers in both barrel and endcap chambers.
In the ATLAS detector, the inner tracking system is placed inside a solenoid providing a 2T axial magnetic field.The electromagnetic and hadron calorimeters are outside the solenoid.The inner tracking detector consists of straw drift tubes interleaved with transition radiators for pattern recognition and electron identification, and several layers of semiconductor strip and pixel detectors providing high-precision space points.The electromagnetic calorimeter is a lead-liquid Argon sampling calorimeter with fine granularity and sampling for shower pointing and π 0 rejection.The endcap hadron calorimeters are based on the same technology as the electromagnetic calorimeter, with copper absorber plates.The barrel hadron calorimeter is an iron-scintillator sampling calorimeter with longitudinal tile geometry.The muon measurements are performed with air-core-toroid muon spectrometers in the barrel and endcap regions.The detectors are monitored drift tubes and resistive plate chambers in the barrel region and cathode strip and thin cap chambers in the forward regions.exploited by optimizing the mass resolutions in the

Searches for a SM-like scalar Higgs boson H
A good mass resolution is particularly important for the inclusive search of the H → γγ channel as the irreducible background from direct pp → γγ + X production is large.The reducible background from pp → γ + jet + X production with the jet fragmenting into a leading isolated π 0 can be reduced below the irreducible one [11].A Higgs boson mass resolution (σ of the Gaussian fit) of 0.65 GeV/c 2 can be obtained with the CMS detector at low luminosity for m H = 100 GeV/c 2 .Figure 4 shows the reconstructed di-photon invariant mass distribution of the inclusive H → γγ signal and the background with m H = 130 GeV/c 2 for 100 fb −1 with the CMS detector.Better signal-to-background ratios but much lower signal rates are obtained when this decay channel is searched for in the associated production processes WH and ttH with an isolated lepton from W → ν and in the H+jet production with a large E T hadronic jet [14,15].
The four-lepton final state from H → ZZ * /ZZ → + − + − has been shown to provide a Higgs boson signature over a wide range of masses from ∼ 130 GeV/c 2 to about ∼ 600 GeV/c 2 [14,15].Backgrounds from the ZZ * , t t and Zb b can be efficiently suppressed with lepton isolation, an upper bound on the lepton impact parameter   significance and cuts on the di-lepton invariant masses.Figure 5 shows the reconstructed four-lepton invariant mass distribution of the H → ZZ * → + − + − signal (with m H = 130, 150 and 170 GeV/c 2 ) and the background for 100 fb −1 .The Higgs boson mass resolution with the CMS detector is found to be < ∼ 1 GeV/c 2 in the four-muon channel [12] and between 1.3 and 1.8 GeV/c 2 in the four-electron channel [11] for 130 ≤ m H ≤ 170 GeV/c 2 .
Around m H ∼ 170 GeV/c 2 , where the H → ZZ * /ZZ branching fraction is smallest, the H → WW * /WW → + − ν ν channel can be exploited [14,15].For m H < ∼ 200 GeV/c 2 , the backgrounds from the WW, t t and Wt and production can be suppressed by taking advantage of WW spin correlations, which turn into small + − opening angles for the signal.Central-jet vetoing suppresses further the t t and Wt backgrounds.As the Higgs boson mass reconstruction is not possible in this channel, a 5% systematic uncertainty has been assumed for the background determination [15].
The Higgs boson production in the gauge boson fusion qq → qqH has been shown to be important for the Higgs boson searches at LHC, in particular in the regions outside the reach of the four-lepton channel for m H < ∼ 130 GeV/c 2 and m H > ∼ 500 GeV/c 2 [16].In this process the hadronic jets from the final state quarks are energetic and distributed in the forward regions while no hadronic jets are expected in the central region.Tagging the forward jets and imposing a veto on central jets suppresses efficiently the backgrounds from t t, W t and the QCD production of Z,γ * +jet, WW and ZZ and hadronic multi-jets.The H → γγ, H → WW * and H → τ + τ − decay channels have been investigated in this production mode for m H < ∼ 150 GeV/c 2 [14,17,18].For m H > ∼ 300 GeV/c 2 advantage has been taken from the final states containing leptons, jets and E miss T with large branching fractions in the H → WW and H → ZZ decay modes [14,15].In the H → WW * → + − ν ν channel the WW spin correlations have been used to further suppress the backgrounds and to reconstruct a transverse mass from the lepton pair and the E miss T with an endpoint at the Higgs boson mass.The qq → qqh production process can be exploited to search for the Higgs boson also in the invisible final states, which could originate from the h → χ • 1 χ • 1 decays in the MSSM.A model-independent 95% CL upper limit of ∼ 15% can be obtained for the Higgs boson branching fraction to invisible final states with an integrated luminosity of 10 fb −1 [17].
Figures 6 and 7 show the statistical significance for the SM Higgs boson for 30 fb −1 in the mass range of 100 ≤ m H ≤ 800 GeV/c 2 (with CMS) and for m H ≤ 200 GeV/c 2 (with ATLAS).In the CMS analysis, the significance is shown with k factors for the signal and for the backgrounds in the inclusive H → γγ channel and for the H → ZZ * /ZZ → + − + − and H → WW * /WW → + − ν ν channels.

Searches for the MSSM Higgs bosons
In the MSSM, the suppression of the Higgs boson couplings to gauge bosons implies different search strategies.At large tanβ, the coupling enhancement to down-type fermions can be exploited to search the H and A bosons in the H,A → µ + µ − and H,A → τ + τ − decay channels in the associated production gg → bbH/A.In this production process, the tagging of the associated b jets suppresses efficiently the Z, γ * and QCD multi-jet backgrounds.A hadronic jet rejection of about 100 with an efficiency of about 50% for genuine b jets is expected with impact parameter measurement.In the gg → bbH/A process, however, the overall b-jet finding efficiencies are lower due to the low E T scale of the associated b jets.The tt and Wt backgrounds with genuine b's and τ 's from the W → τ ν τ decays can be suppressed with a veto on an additional central jet.
For the H,A → τ + τ − decay channels, tagging of the τ 's with impact parameter measurement can be used to further suppress the Z → + − and the QCD multi-jet backgrounds.To use the hadronic τ decays in the lepton-plus-τjet and two-τ -jet final states from the H,A → τ + τ − decay, an efficient hadronic τ trigger and τ -jet identification method is required to suppress QCD multi-jet and W+jet backgrounds with fake τ 's from hadronic jets.A hadronic jet suppression of ∼ 1000 has been shown to be possible with an efficiency of 20-30% for genuine τ jets, taking advantage of the narrowness and low multiplicity of the jets from hadronic τ decays [14].The Higgs boson mass can be reconstructed in the H,A → τ + τ − channels from E miss T and the visible τ momenta exploiting the neutrino collinearity with the parent τ direction.The mass resolution improves for a decreasing opening angle between the two τ directions and is sensitive to the precision of the E miss T measurement.The eµ, two-lepton, lepton-plus-τ -jet and two-τ -jet final states were studied for the H, A → τ + τ − decay modes [14,15].Figure 8 shows the reconstructed τ + τ − invariant mass distribution for the eµ final state and for the total background with m A = 200 GeV/c 2 , tanβ = 30 for 30 fb −1 .The mass resolution with the CMS detector for this final state with ∆φ τ τ < 175 • is ∼ 25% and is better for the lepton+τ jet (∼ 20%) and two-τ jet (∼ 15%) final states.
Figure 9 shows the reconstructed µ + µ − invariant mass distribution of the gg → bbH/A, H/A → µ + µ − signal, the Z, γ * background and the tt background with m A = 130 GeV/c 2 , tanβ = 30 for 20 fb −1 [14].A mass resolution of ∼ 2% can be obtained in this channel with the CMS detector.In the major part of the MSSM parameter space,  this resolution is not enough to separate the signals from A and H, but may allow the measurement of the Higgs boson total width from the superposition of the A and H signals at large tanβ.
To search for the heavy charged Higgs bosons the H ± → τ ν τ decay channels with hadronic τ decays can be used in tt events in the region m H ± < m top , in the associated production process gg → btH ± for m H ± > m top and also in the direct production qq → H ± for m H ± > m top [14,15].In these channels, the tt and Wt backgrounds with genuine τ 's can be suppressed exploiting the different helicity correlations in the H ± → τ ν τ and the W ± → τ ν τ decays.Due to a more energetic leading pion from the H ± decay a large background suppression can be obtained requiring at least 80% of the visible τ -jet energy to be carried by a single charged pion.For m H ± < m top , the H ± signal is characterized by an excess of τ 's in tt events relative to electrons and muons.For m H ± > m top , in the purely hadronic events with hadronic top decays, the E miss T originates mainly from the H ± → τ ν τ decay, making possible a reconstruction of the transverse mass from the τ jet and E miss T with an endpoint at m H ± for the signal and at m W for the residual backgrounds.
Figure 10 shows the 5σ-discovery potential of CMS for the heavy neutral MSSM Higgs bosons H and A and for the charged Higgs bosons H ± as a function of m A and tanβ with maximal stop mixing for 30 fb −1 .The effect of the variation of the µ parameter on the discovery potential for the H → τ + τ − → two τ -jet channel is also shown in Fig. 10. Figure 11 shows the discovery potential for the lighter scalar MSSM Higgs boson h as a function of m A and tanβ, assuming maximal stop mixing, m top = 175 GeV/c 2 and m SUSY = 1 TeV/c 2 for 30 fb −1 .The region of large m A and tanβ is covered with h → γγ in the inclusive production, h → bb in the associated production tth, h → ZZ * → + − + − and h → τ + τ − → + τ jet and h → γγ in the gauge boson fusion qq → qqh.The region m A > ∼ 400 GeV/c 2 at large tanβ is not accessible with the h → bb and h → τ + τ − decay channels with an integrated luminosity as low as 30 fb −1 due to the decreasing branching fractions with increasing m h .As the branching fraction for the h → ZZ * decay decreases fast with decreasing m h , the discovery potential for the h → ZZ * → + − + − channel is particularly sensitive to the MSSM parameters (mainly to the amount of stop mixing) and the top mass through the maximum value of m h .With the recent value of the top quark mass, the discovery potential in this channel is expected to improve.The parameter space for 90 < ∼ m A < ∼ 130 GeV/c 2 , where the lighter scalar is not SM-like, can be partly covered with the h → µ + µ − and h → τ + τ − decay channels with b tagging in the gg → bbh production process [15].

Specific SUSY searches
The decays into SM particles may provide access to the heavy MSSM Higgs bosons only at large tanβ.The small and medium tanβ values could be partly explored with Higgs boson decays to gauginos.If the gaugino masses     are small enough, the branching fractions for the H, A → χ • 2 χ • 2 and H ± → χ • 2,3 χ ± 1,2 decays can be sizeable.If the sleptons are also light (m ˜ < ∼ 500 GeV/c 2 ) the branching fraction for the χ • 2 → ˜ → χ • 1 + − decay can be as large as ∼ 55% and four-lepton final states can be exploited.Figure 12 shows the 5σ-discovery region for the H, A → χ • 2 χ • 2 decay channel with the SUSY parameters fixed to m A = 350 GeV/c 2 , M 2 = 120 GeV/c 2 , µ = − 500 GeV/c 2 , M q,g = 1000 GeV/c 2 and M ˜ = 250 GeV/c 2 for 30 and 100 fb −1 .The reduction of the discovery region with increasing M 2 is also shown.
In the MSSM, Higgs bosons can also be produced as decay products of gauginos in the squark and gluino cascades.More specifically, squarks and gluinos can decay to heavy charginos and neutralinos, χ ± 2 , χ • 3 and χ • 4 .If kinematically allowed, these particles decay into the lighter chargino and neutralinos, χ ± 1 , χ • 1 and χ • 2 and Higgs bosons.Squarks and gluinos can also decay directly to the light gauginos χ ± 1 and χ • 2 which then decay to the lightest neutralino and Higgs bosons.These events are characterized by large E miss T and large jet multiplicity, which can be used to suppress efficiently the SM backgrounds.Figure 13 shows the distribution of the reconstructed invariant bb mass of the χ • 2 → h, H, A + χ • 1 , h, H, A → bb signal and the SUSY and SM background with m A = 150 GeV/c 2 , tanβ = 5, M 2 = 350 GeV/c 2 , µ = 1000 GeV/c 2 , m g = 1200 GeV/c 2 , m q = 800 GeV/c 2 and m ˜ = 500 GeV/c 2 for 100 fb −1 [19].The discovery potential covers the region m A < ∼ 200 GeV/c 2 and is independent of tanβ.

Measurements of Higgs boson properties
Figure 14 shows the expected precision of the measurement of the SM Higgs boson mass for 300 fb −1 with the ATLAS detector [15].The precision is limited with the uncertainty of the energy scale estimated to be 0.1% for muons, electrons and photons and 1% for hadronic measurements.Best precision is obtained with the H → γγ and H → ZZ * → + − + − channels.The total decay width of the SM Higgs boson can be measured directly in the H → ZZ → + − + − channel for m H > 200 GeV/c 2 .The expected precision is about 10% for 300 fb −1 [15].For m H < 200 GeV/c 2 , indirect methods (with a similar final precision) can be used with decay modes in the gluongluon fusion and weak gauge boson fusion production, assuming insignificant contributions from unknown decay modes [20].The ratios of couplings and branching fractions have the advantage of partial cancellation of systematic uncertainties and can be measured with a precision better than 60% already with 30 fb −1 [21].Measurements of Higgs boson spin and CP quantum numbers have been shown to be possible in the H → ZZ → + − + − channel exploiting the helicity correlations in the decay angular distributions [22].In the MSSM, the value of tanβ can be measured from event rates in the H, A → τ + τ − , H, A → µ + µ − and in H ± → τ ν τ decay modes exploiting the tan 2 β dependence of the event rates at large tanβ.The uncertainty of the tanβ measurement from the event rates in the H, A → τ + τ − channels is shown in Fig. 15 in the SUSY scenario given in Section 1 and assuming a 20% theoretical scale uncertainty and a 5% uncertainty in the luminosity measurement [23].Uncertainty due to SUSY parameter measurement is not included.

Conclusions
The SM Higgs boson is expected to be found at the LHC with several decay channels over the full expected mass range in the CMS and ATLAS detectors.In the region 130 GeV/c 2 < ∼ m H < ∼ 500 GeV/c 2 the discovery is possible already with an integrated luminosity of 10 fb −1 or less with the H → WW * /WW and H → ZZ * /ZZ decay channels.The light SM Higgs boson with m H < ∼ 150 GeV/c 2 is expected to be found in the inclusive h → γγ channel, in the h → bb decay in the associated ttH production and the weak boson fusion channels with decays to H → γγ, H → WW * and h → τ + τ − .In the MSSM, the lighter scalar Higgs boson is expected to be found at large m A and tanβ with the inclusive h → γγ and h → ZZ * → + − + − channels, with h → τ + τ − channel in the gauge boson fusion qq → qqh already with 30 fb −1 and with the h → bb decay channel in the associated production tth, with 60 fb −1 .The heavy neutral MSSM Higgs bosons can be found through the H, A → µ + µ − and H, A → τ + τ − decays channels at large tanβ.The two-lepton and lepton-plus-τ -jet final states from the H, A → τ + τ − decays cover the domain m A < ∼ 300 GeV/c 2 and tanβ > ∼ 10 already with 30 fb −1 .The two-τ -jet final states extend the sensitivity up to m A ∼ 800 GeV/c 2 with tanβ > ∼ 35.The heavy scalar H is accessible also in the H → τ + τ − channel in the gauge boson fusion for m A < ∼ 120 GeV/c 2 with 30 fb −1 .For the searches of the charged Higgs bosons the H ± → τ ν τ decay channel with hadronic τ decays plays a crucial rule.For m H ± < m top the reach is for m A < ∼ 140 GeV/c 2 in the tt events.The heavy charged Higgs bosons can be found in the associated production tH ± at large tanβ ( > ∼ 20-30) and in the qq → H ± fusion in a small part of the parameter space at large tanβ.
Part of the parameter space left outside the reach with SM particles at intermediate and small tanβ region can be covered with the Higgs boson decays to neutralinos in the H, A → χ • i χ • j decay channel with the four-lepton final states.If the sleptons are light the discovery reach is for 200 GeV/c 2 < ∼ m A < ∼ 450 GeV/c 2 for M 2 ≤ 120 GeV/c 2 for an integrated luminosity of 100 fb −1 .For the Higgs boson production from the gaugino decays in the g, q cascades the region m A < ∼ 200 GeV/c 2 is accessible already with 30 fb −1 , independent of tanβ.

Figure 1 :
Figure 1: Branching fractions for the SM Higgs boson H as a function of the Higgs boson mass m H [9].

Figure 2 :
Figure 2: Branching fractions for the MSSM Higgs bosons H and A for tanβ = 40 as a function of the MSSM pseudoscalar mass m A [9].

Figure 6 :
Figure 6: Expected statistical significance for the SM Higgs boson as a function of m H for 30 fb −1 with the CMS detector.Results of NLO analysis with k factors for both signal and background are shown for the inclusive H → γγ, H → ZZ * /ZZ → + − + − and H →→ + − ν ν channels.

Figure 7 :
Figure 7: Expected statistical significance for the SM Higgs boson as a function of m H for m H < 200 GeV/c 2 for 30 fb −1 with the ATLAS detector.

Figure 10 :
Figure10: The 5σ-discovery potential for the heavy MSSM Higgs bosons H, A and H ± as a function of m A and tanβ with maximal stop mixing for 30 fb −1 with the CMS detector.

Figure 11 :
Figure 11: The 5σ-discovery potential for the lighter scalar MSSM Higgs boson as a function of m A and tanβ with maximal stop mixing for 30 fb −1 with the CMS detector.The potential for the tth, h → bb channel and for the h → γγ channel in the qq → qqh process are shown for 60 fb −1 .

Figure 14 :
Figure 14: Expected precision of the SM Higgs boson mass measurement as a function of m H for 300 fb −1 with the ATLAS detector.

Figure 15 :
Figure 15: Expected precision of the tanβ measurement in the MSSM in the H/A → τ τ decay channels as a function of m A for 30 fb −1 with CMS detector.