Dimuon asymmetry and electroweak precision with Z Seodong Shin Seoul National University, Seoul, Korea TeV 2011, 20 May 2011 Work in progress with H.D. Kim and R. Dermisek
Outline Introduction : Same charge dimuon asymmetry by D0 New CP violation source in a Z model Electroweak precision with Z Conclusions
Busy days with news from Tevatron Reason of this workshop!! Lots of 2-3σ deviations... Top forward-backward asymmetry Dijet excess : single lepton + missing minv ET Boosted top, Multi-b events... Same charge dimuon asymmetry from D0 (1 year ago)
Some anomalies can be washed out... Underestimated SM effects Re-analysis of the data Change in the calibrations Such research already exist...
A new neutral gauge boson Z??? Many papers exist to explain the CDF results : Today s talks!!!!! Z from SU(6)XSU(2) GUT arxiv:1104.5500 by Jihn E. Kim and Seodong Shin No leptophobic Z from GUT E6 Z to explain the dimuon asymmetry from D0 Phys. Rev. D 83, 036003 (2010) [arxiv:1010.5123] by Jihn E. Kim, Min-Seok Seo and Seodong Shin arxiv:1010.1333 by A.K. Alok, S. Baek and D. London
Same-charge dimuon asymmetry in D0 Asymmetry in semi-leptonic decays of Bs,d meson A b s = N ++ N N ++ + N N++ : # of events μ+μ+ N : # of events μ μ As 0 : CP from mixing D0 2010 arxiv:1005.2757 PR D82 6.1 fb ¹ A b s = (9.52 ± 2.51 ± 1.46) 10 3 3.2σ deviation from the SM value A bsm s =( 2.3 +0.5 0.6 ) 10 4 Additional CP violation source in Bs,d mixing
Obtain A b s from Bd mixing + Bs mixing a d s Γ(B d µ + X) Γ(B d µ X) Γ(B d µ + X) + Γ(B d µ X) a s s Γ(B s µ + X) Γ(B s µ X) Γ(B s µ + X) + Γ(B s µ X) where the relation at 1.96 TeV is A b s =(0.506 ± 0.043)a d s +(0.494 ± 0.043)a s s From the B factories a d s = (4.7 ± 4.6) 10 3 CDF result of 1.6 fb ¹ & direct measure (a s s) ave = (12.7 ± 5.0) 10 3 a s s by D0 2.5σ from a ssm s =(2.1 ± 0.6) 10 5
Bs,d - Bs,d mixing B 0 B 0 i d dt B 0 = M i Γ 2 B 0 M and Γ : 2 2 hermitian mass and decay matrices Mixing via off-shell (dispersive) intermediate states and on-shell (absorptive) intermediate states M q =2 M q 12 Γ q =2 Γ q 12 cos φ q φ q = Arg. M q 12 Γ q 12 φ SM d =( 9.6 +4.4 5.8 ) 10 2 φ SM s =(4.7 +3.5 3.1 ) 10 3
a q s =ImΓq 12 M q 12 = Γq 12 M q 12 sin φ q = Γ q M q tan φ q M s = 17.77 ± 0.10(stat.) ± 0.07(sys.) ps 1 = (11.7 ± 0.07 ± 0.05) 10 12 GeV CDF measurement 1.6 fb ¹ With Γ s s, SM 12 =Γ only even with sin φ 12 s =1 It is impossible to obtain the central value of (a s s) ave For convenience, let s define Γ q NP 12 Γ q SM 12 h q e i2 σ q, M q NP 12 M q SM 12 h q e i2σ q
New CP violation source from Z Tree level mixing : M₁₂ What about Γ₁₂? Remind that ( bs)( ττ) V,A is safe from various exp. C.W.Bauer and N.D. Dunn, arxiv:1006.1629 Br.( B s τ + τ ) < 5% Br.( B X s τ + τ ) < 5% Not so severe constraints O(1) h s
h s 0.3 for every σ s h s < 2.5 for some σ s hs 1 is safely obtained (With the constraints of Ms, s, sinφs ) Z of a non-anomalous extra U(1) gauge symmetry can be obtained when the U(1) charge is assigned to be flavor non-universal in left-handed quarks. Possible to construct a model not violating the present constraints such as b s and Bs μ+μ
Mass of Z boson? Couplings? In general, assume (g sb) L,R : Z s L,R b L,R (g ττ ) L,R : Z τ L,R τ L,R With (gsb)l only h s =3.858 10 5 ρ sb 2 L ρ sb L = (g sb ) L g M Z M Z h s ρ sb L V cb M Z M Z (gττ ) L +(g ττ ) R g 2 Upper limit Fixed as 0.04 M Z M Z g ττ lower limit
Even in the case (g ττ ) L =(g ττ ) R and MZ = MZ Large coupling Perturbativity problem? Heavier Z increases the coupling allowed by the asymmetry
What happens if we consider g bb g ee and? Constraints from mesons such as decay Constraints of the Electroweak Precision data from LEP and SLC Explain some discrepancies in the Z-pole observables by Z with the above couplings PRL (2000) by J. Erler and P. Langacker PLB (1995) by F. Caravaglios and G.G. Ross arxiv:1105.0773 by R. Dermisek, S.G. Kim and A. Raval Case MZ MZ
Z pole observables Quantity Value Standard Model Pull Dev. M Z [GeV] 91.1876 ± 0.0021 91.1874 ± 0.0021 0.1 0.0 Γ Z [GeV] 2.4952 ± 0.0023 2.4954 ± 0.0009 0.1 0.1 Γ(had) [GeV] 1.7444 ± 0.0020 1.7418 ± 0.0009 Γ(inv) [MeV] 499.0 ± 1.5 501.69 ± 0.07 Γ(l + l )[MeV] 83.984 ± 0.086 84.005 ± 0.015 σ had [nb] 41.541 ± 0.037 41.484 ± 0.008 1.5 1.5 R e 20.804 ± 0.050 20.735 ± 0.010 1.4 1.4 R µ 20.785 ± 0.033 20.735 ± 0.010 1.5 1.6 R τ 20.764 ± 0.045 20.780 ± 0.010 0.4 0.3 R b 0.21629 ± 0.00066 0.21578 ± 0.00005 0.8 0.8 R c 0.1721 ± 0.0030 0.17224 ± 0.00003 0.0 0.0 A (0,e) FB 0.0145 ± 0.0025 0.01633 ± 0.00021 0.7 0.7 A (0,µ) FB 0.0169 ± 0.0013 0.4 0.6 A (0,τ) FB 0.0188 ± 0.0017 1.5 1.6 A (0,b) FB 0.0992 ± 0.0016 0.1034 ± 0.0007 2.7 2.3 A (0,c) FB 0.0707 ± 0.0035 0.0739 ± 0.0005 0.9 0.8 A (0,s) FB 0.0976 ± 0.0114 0.1035 ± 0.0007 0.6 0.4 s 2 l (A(0,q) FB ) 0.2324 ± 0.0012 0.23146 ± 0.00012 0.8 0.7 0.2316 ± 0.0018 0.1 0.0 A e 0.15138 ± 0.00216 0.1475 ± 0.0010 1.8 2.2 0.1544 ± 0.0060 1.1 1.3 0.1498 ± 0.0049 0.5 0.6 A µ 0.142 ± 0.015 0.4 0.3 A τ 0.136 ± 0.015 0.8 0.7 0.1439 ± 0.0043 0.8 0.7 A b 0.923 ± 0.020 0.9348 ± 0.0001 0.6 0.6 A c 0.670 ± 0.027 0.6680 ± 0.0004 0.1 0.1 A s 0.895 ± 0.091 0.9357 ± 0.0001 0.4 0.4 Pull : Free input of mh Dev. : input of = 117 GeV mh With MZ MZ Strong constraint Explain these LR-asymmetry for hadronic final states
Goal : Explain the same-charge dimuon asymmetry and the EW precision data simultaneously with Z With g sb g ττ g bb g ee Upper bound by EW precision?
Conclusions Additional neutral gauge boson Z is being focussed on due to several Tevatron results The same-charge dimuon asymmetry can be also explained by Z We will see if the dimuon asymmetry and the EW precision data can be simultaneously explained by a Z model
Thank you