m H tanβ 30 LHC(40fb -1 ): LEP2: e + e Zh m A (GeV)

Transcription

1 Charged Higgs Bosons Production in Bottom-Gluon Fusion Tilman Plehn, Madison MSSM Higgs Bosons at the LHC Why Bottom Parton Description? QCD Corrections -QCD Corrections

2 MSSM Higgs Bosons at the LHC MSSM Higgs Sector: Higgs mass m q ~ = 5 GeV, m g ~ = 5 GeV, tanβ = 4 M = m q ~, µ = m q ~ tree level 2 loop, no mixing 2 loop, max mixing two doublets, coupling to up and down type fermions! five physical states h o ;H o ;A o ;H ±! mixing of scalars to mass eigenstates [mixing angle ff]! more predictive than Standard Model (2-loop limits on h o mass: S. Heinemeyer et al., R. Zhang) m h M A conveniently expressed as function of m A and tan fi v 2 =v charged Higgs Yukawa coupling ( tan fi + m t = tan fi) LHC Search Channels: multitude of channels in ATLAS TDR (pre-lep2) no-lose theorem in WBF h! fifi tanβ mostly light scalar Higgs boson 5 2 LHC(4fb - ): VV H ττ LEP2: e + e Zh VV h ττ M A Tell it is 2HDM (MSSM?) ) look for heavy Higgs bosons: H ;A! fifi;μμ in gluon fusion tanβ H ±! νfi;tb in pp! th ;W + H ;H + H [e.g. D.P.Roy] There is no other conclusive way but to find these particles! m A (GeV)

3 Bottom Parton Description =4.6 GeV /σ tot dσ/d y b -y cm (gg b th ) Exclusive Production Process gg! μ bth :. =.46GeV.5 = GeV = 5 GeV = 25 GeV y b -y cm! collinear bottom jets from gluon splitting, regularized by! large logarithms in total cross section log(p T;b = )! asymptotic cross section behavior dff=dp T;b / p T;b =m 2 T;b! solve for factorization scale p max T;b ο μ F 2 p T,b dσ/dp T,b (gg b th )! plateau in hadronic vs. partonic cross section (limitations by gluon parton density at LHC) = GeV =5 GeV =4.6 GeV =.46 GeV =25 GeV 2 3 p T,b Why the Inclusive Process bg! th? bottom jet at large rapidity (collinear) bottom jet with low transverse momentum (soft)! hard to see or even tag ) analysis gg! th + X! resum above logarithms for numerical improvement m /σ tot dσ/d y b (gg b th b =4.6 GeV ). =.46 GeV.5 = GeV = 5 GeV = 25 GeV y b.4 /σ tot dσ/dp T,b (gg b th ).3 =4.6 GeV = GeV.2 = 5 GeV = 25 GeV p T,b! remaining error O(m 2 b =M 2 ) [Campbell, Ellis, Maltoni, Willenbrock]! n.b.: NLO calculation to interpolate between gg! μ bth and bg! th

4 QCD Corrections to Inclusive Channel Next-to-leading Order QCD Calculation: leading order uncertainty large for bg! th e.g. mass definition: MS or pole mass for y b;t? complete set of virtual and real corrections running top and bottom Yukawa coupling! NLO correction +3% 4% perturbatively stable [Zhu] NLO: gb th LO : gb th LO : gg b th σ tot (pp th +X) [pb] ( running mass) pole mass K (pp th +X) tanβ = µ = 4m av µ = m av µ = m av / Scale Dependence in NLO: generic cancellations for μ R μ F [Harlander & Kilgore] renormalization scale dependence numerically dominant μ R ο (m t + )=2 natural choice [c.f. Higgs decays, Melnikov] σ tot (pp th +X) [pb] =25 GeV NLO µ F =µ R LO µ R =m av µ F =m av - µ/m av factorization scale dependene critical for μ F ο ο =3 (m t + )=2 from exclusive process μ F! NLO scale dependence ±2%! well defined limit μ F! returns exclusive process at NLO Distributions in NLO:.6 /σ tot dσ/dp T,H (pp th +X) Higgs transverse momentum softened (gluon density).4.2 =25GeV NLO LO =5GeV Higgs rapidity not symmetric (gluon splitting) p T,H

5 -QCD Corrections -QCD Loop Contributions: infrared finite but ultraviolet divergent loops parameterized by K = +ff =ff NLO () universal corrections y b! y b =( + ) [Carena, Garcia, Nierste, Wagner] (a). K (pp th +X) tanβ = 3 = 25 GeV = 5 GeV µ< µ> m SUGRA (2) remaining explicit loop diagrams [Gao, Lu, Xiong, Yang]! corrections dominant for tan fi & (dependent on sign of μ)! explicit loop corrections negligible. 5% for generic msugra Decoupling of Running Parameters: ff s (μ R );y b;t (μ R ) heavy particle loops ultraviolet divergent! counter terms for Standard Model parameters! contributions to beta functions (d). K, no dec (pp th +X) tanβ = 3 = 25 GeV = 5 GeV µ< µ> m SUGRA! explicit decoupling necessary: ;t (μ R )! ;t (μ R )[ + ff s =(4ß)C F log(μ 2 R =m2 heavy )]

6 Conclusions heavy Higgs bosons necessary to tell it might be the MSSM charged Higgs boson production promising at LHC for large tan fi bottom initiated process bg! th appropriate NLO : inclusive process well defined NLO 2 : 3% 4% enhancement of ff tot in 2HDM NLO 3 : remaining scale uncertainty. 2% NLO 4 : corrections dominant in MSSM for large tan fi NLO 5 : non-factorizable corrections negligible in MSSM Let's go and get data!

7 6 5 m q ~ = 5 GeV, m g ~ = 5 GeV, tanβ = 4 Higgs mass M = m q ~, µ = m q ~ tree level 2 loop, no mixing 2 loop, max mixing m h M A Heinemeyer, Hollik, Weiglein

8

9 tanβ LHC(4fb - ): VV H ττ VV h ττ 5 LEP2: e + e Zh M A

10 tanβ m A (GeV) Assamagan, Coadou, Deandrea

11 =4.6 GeV /σ tot dσ/d y b -y cm (gg b th ). =.46GeV.5 = GeV = 5 GeV = 25 GeV y b -y cm

12 2 p T,b dσ/dp T,b (gg b th ) p T,b dσ/dp T,b (gg b th ) 5 3 = GeV =25 GeV no luminosity: P g (x)= =4.6 GeV =.46 GeV p T,b dσ/dp T,b (gg b bh ) 2. 2 =5 GeV =4.6 GeV =.46 GeV = GeV =4.6 GeV p T,b dσ/dp T,b (gg b bh ) =25 GeV 2 3 p T,b =35 GeV =4.6 GeV 2 3 p T,b

13 =4.6 GeV /σ tot dσ/d y b (gg b th ). =.46 GeV.5 = GeV = 5 GeV = 25 GeV y b /σ tot dσ/dp T,b (gg b th ) =4.6 GeV = GeV = 5 GeV = 25 GeV p T,b

14 - σ tot (pp th +X) [pb] ( running mass) pole mass -2 NLO: gb th LO : gb th LO : gg b th K (pp th +X) tanβ = 3 5 µ = 4m av µ = m av µ = m av /

15 .8.6 σ tot (pp th +X) [pb] =25 GeV NLO.4.2 µ F =µ R µ R =m av µ F =m av LO - µ/m av

16 .6.4 /σ tot dσ/dp T,H (pp th +X) NLO LO.2 =25GeV =5GeV p T,H /σ tot dσ/dy H (pp th +X).4 NLO LO.2 =25GeV =5GeV y H

17 . K (pp th +X).5 = 25 GeV tanβ = 3 (a) = 5 GeV µ< µ> m.95 b m SUGRA.2. K (pp th +X) = 25 GeV tanβ = 5 (b).9.2. = 5 GeV µ< µ> m.9 b m SUGRA

18 . K (pp th +X).5 = 25 GeV tanβ = 3 (c) = 5 GeV µ= 26GeV µ=+26gev m SUGRA. K, no dec (pp th +X).5 = 25 GeV tanβ = 3 (d) = 5 GeV µ< µ> m.95 b m SUGRA