Coloron Models and LHC Phenomenology

Transcription

1 Coloron Models and LHC Phenomenology Elizabeth H. Simmons Michigan State University - New Strong Dynamics - Models - LHC Phenomenology - Other Phenomenology - Conclusions SCGT 12 December 5, 2012

2 LHC s rediscovery and new particle After years of work pay off... What s next?

3 Our Quest in The BSM Landscape SUSY Composite Higgs Dark Matter Extra Dimensions? Flavor L H C LHC References

4 New Strong Dynamics New colored gauge bosons Classic Axigluon: P.H. Frampton and S.L. Glashow, Phys. Lett. B 190, 157 (1987). Topgluon: C.T. Hill, Phys. Lett. B 266, 419 (1991). Flavor-universal Coloron: R.S. Chivukula, A.G. Cohen, & E.H. Simmons, Phys. Lett. B 380, 92 (1996). Chiral Color with gl gr: M.V. Martynov and A.D. Smirnov, Mod. Phys. Lett. A 24, 1897 (2009). New Axigluon: P.H. Frampton, J. Shu, and K. Wang, Phys. Lett. B 683, 294 (2010). Other color-octet states: KK gluon: H. Davoudiasl, J.L. Hewett, and T.G. Rizzo, Phys. Rev. D63, (2001) B. Lillie, L. Randall, and L.-T. Wang, JHEP 0709, 074 (2007). Techni-rho: E. Farhi and L. Susskind, Physics Reports 74, 277 (1981). Recent catalog of colored states: Color sextets, colored scalars, low-scale scale string resonances... T. Han, I. Lewis, Z. Liu, JHEP 1012, 085 (2010).

5 New Strong Dynamics... and A t fb Coloron might impact A t FB at FNAL: L. M. Sehgal and M. Wanninger, Phys. Lett. B 200, 211 (1988). D. Choudhury, R.M. Godbole, R. K. Singh, and K. Wagh, Phys. Lett. B 657, 69 (2007). P. Ferrario and G. Rodrigo, J. High Energy Phys. 02 (2010) 051. M.V. Martynov and A. D. Smirnov, arxiv: Q. H. Cao, D. McKeen, J. L. Rosner, G. Shaughnessy, and C. E. M. Wagner, Phys. Rev. D 81, (2010). P. Ferrario and G. Rodrigo, Proc. XVIII Int l Workshop on Deep-Inelastic Scattering, April 19-23, 2010, Firenze. R.S. Chivukula, E.H. Simmons, and C.-P. Yuan, Phys. Rev. D82 (2010). G. Rodrigo and P. Ferrario, 3rd Int l Workshop on Top Quark Physics, Brugges, Belgium, 31 May to 4 Jun G. Rodrigo and P. Ferrario arxiv: [hep-ph]... anti-top proton beam Anti-proton beam top

6 Models

7 Coloron Models: Gauge Sector u SU(3) 1 SU(3) 2 h 1 h 2 SU(3)1 x SU(3)2 color sector with M 2 = u2 4 h 2 1 h 1 h 2 h 1 h 2 h 2 2 unbroken subgroup: SU(3)1+2 = SU(3)QCD gluon state: G A µ = cos A A 1µ +sin A A 2µ h 1 = g s cos h 2 = g s sin couples to: g S J µ G g S(J µ 1 + J µ 2 ) coloron state: Cµ A = sin A A 1µ + cos A A M 2µ C = p u qh h2 2 couples to: g S J µ C g S( J µ 1 tan + J µ 2 cot ) low-energy current-current interaction: L 2 FF = g 2 S 2M 2 C J µ C J Cµ

8 Coloron Models: Quark Charges u SU(3) 1 SU(3) 2 h 1 h 2 g S J µ G g S(J µ 1 + J µ 2 ) g S J µ C g S( J µ 1 tan + J µ 2 cot ) low-energy current-current interaction: L 2 FF = g 2 S 2M 2 C J µ C J Cµ Depending on how quarks transform under SU(3)1 x SU(3)2 the presence of colorons may impact LHC dijet mass distribution (or angular distribution) kinematic distributions of tt or bb final states asymmetry in top-quark production: A t FB FCNC processes: K K,D D, B B mixing, b! s precision EW observables: delta-rho, Rb

9 Patterns of Quark Charges SU(3)1 SU(3)2 model pheno. (t,b)l ql tr,br qr coloron dijet qr (t,b)l ql tr,br tr,br (t,b)l ql qr ql (t,b)l tr,br qr ql tr,br (t,b)l qr new axigluon dijet, A t FB, FCNC ql qr (t,b)l tr,br topgluon dijet, tt, bb, FCNC, Rb... tr,br qr (t,b)l ql classic axigluon dijet, A t FB ql tr,br qr (t,b)l q = u,d,c,s

10 LHC Phenomenology

11 LHC Limits on Colorons LHC searches for colorons in dijet constrain M C > 3.5 TeV [pb] σ q* Observed 95% CL upper limit Expected 95% CL upper limit 68% and 95% bands L dt = 4.8 fb s = 7 TeV ATLAS Mass [GeV] But these calculations have treated the colorons only at LO and QCD to NLO (or beyond)... we can do better!

12 Coloron Production q LO vs NLO production cross-section pt of coloron C q q q q q C q C q q q q q

13 Colorons at NLO virtual corrections real corrections + + R.S.Chivukula, A.Farzinnia, R.Foadi, EHS arxiv:

14 Impact of NLO Corrections σ pb r L πr R NLO LO s B A HpbL σ r L πr R m F HTeVL M C HTeVL K-factor: NLO/ LO 30% 30% of produced colorons have p T > 200 GeV! RSC, Farzinnia, Foadi, EHS arxiv:

15 Impact of NLO Corrections σ pb r L πr R NLO LO s B A HpbL σ r L πr R m F HTeVL M C HTeVL scale dependence at LO: 30% at NLO: 2% K-factor: NLO/ LO 30% 30% of produced colorons have p T > 200 GeV! RSC, Farzinnia, Foadi, EHS arxiv:

16 Impact of NLO Corrections σ pb r L πr R NLO LO s B A HpbL σ r L πr R m F HTeVL M C HTeVL scale dependence at LO: 30% at NLO: 2% K-factor: NLO/ LO 30% Axigluon mass limit from CMS stronger when NLO included 30% of produced colorons have p T > 200 GeV! RSC, Farzinnia, Foadi, EHS arxiv:

17 Beyond Production: Suppose we discover a coloron... What then? Remember the diversity of models: How to establish which coloron has been found?

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19 New Mode: W+C a probes Chiral Couplings Different production modes probe several combinations of the coloron s couplings to RH and LH fermions: g R Dijet Zjj pp! C a + W [Z]! jj` [``] 1 2 q W (Z) l (l + ) ν (l ) j q j l (l + ) Wjj g L q C j q C W (Z) j ν (l ) l (l + ) l (l + ) W (Z) ν (l ) W (Z) ν (l ) q C j q C j A. Atre, R.S.Chivukula, P. Ittisamai, EHS arxiv: q j q j

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21 W+C a : Heat Map of Significance all of these heat maps are for Mc = 3.5 TeV at 14 TeV LHC g R W+C a Dijet Sensitivity 14TeV 100fb-1 Γ/M=0.05 Γ/M=0.10 Γ/M=0.20 Γ/M=0.30 LHC 14 TeV L = 10 fb -1 MC = 3.5 TeV g L significance >5σ 5σ 4σ 3σ 2σ <2σ g R W+C a Dijet Sensitivity 14TeV 100fb-1 Γ/M=0.05 Γ/M=0.10 Γ/M=0.20 Γ/M=0.30 LHC 14 TeV L = 100 fb -1 MC = 3.5 TeV g L significance >5σ 5σ 4σ 3σ 2σ <2σ grey ring is excluded by 7 TeV LHC dijet searches with 5 fb -1 of data g R Z+C a Dijet Sensitivity 14TeV 100fb-1 Γ/M=0.05 Γ/M=0.10 Γ/M=0.20 Γ/M=0.30 LHC 14 TeV L = 10 fb -1 MC = 3.5 TeV significance >5σ 5σ 4σ 3σ 2σ <2σ g R Z+C a Dijet Sensitivity 14TeV 100fb-1 Γ/M=0.05 Γ/M=0.10 Γ/M=0.20 Γ/M=0.30 LHC 14 TeV L = 100 fb -1 MC = 3.5 TeV significance >5σ 5σ 4σ 3σ 2σ <2σ g L g L

22 W+C a : Heat Map and Afb range g R Allowed by AFB Γ/M=0.20 Γ/M=0.05 Γ/M=0.10 Dijet Exclusion 7 TeV 4.8 fb-1 Dijet Sensitivity 14TeV 100fb-1 LHC 14 TeV L = 10 fb -1 M C = 3.0 TeV Allowed by AFB significance >5σ 5σ 4σ 3σ 2σ <2σ g R Allowed by AFB Γ/M=0.20 Γ/M=0.05 Γ/M=0.10 Dijet Exclusion 7 TeV 4.8 fb-1 Dijet Sensitivity 14TeV 100fb-1 LHC 14 TeV L = 100 fb -1 M C = 3.0 TeV Allowed by AFB significance >5σ 5σ 4σ 3σ 2σ <2σ g L g L

23 Precision Phenomenology

24 Precision EW Tests Coloron exchange does impact at one-loop W, Z but since c t, b m4 t M 2 W M 2 C the size of the effect is small ln apple M 2 c m 2 t Likewise, coloron exchange across the vertex yields effects proportional to m 2 b Zb b which are negligible New weak-charged states would give larger effects...

25 FCNC in Coloron Models Coloron exchange can produce FCNC if the coloron coupling to quarks are flavor non-universal The total rate of FCNC will depend quite strongly on how flavor is implemented overall in the model Are there other states that quarks mix with? Are there additional composite states made from quarks, whose exchange can boost FCNC s? Let s look at a specific implementation

26 A New Toy Topgluon Model R.S. Chivukula, EHS, N. Vignaroli (2012) in preparation

27 Our Toy Topgluon Model particles SU(3)1 SU(3)2 SU(2)W 3rd generation (t,b)l quarks tr,br light quarks (u,d)l (c,s)l ur,dr cr,sr vector quarks QL,QR light scalar # $ φ heavy scalar Φ 3 3* 1 R.S. Chivukula, EHS, N. Vignaroli (2012) in preparation

28 Generational Mixing in Toy Model SU(3)1 x SU(3)2 x SU(2)W (1,1,2) (3, 3 *,1) <φ> <Φ> X tr, br QL QR (u,d)l (c,s)l (3,1,1) (3,1,2) (3,1,2) (1,3,2)

29 FCNC in Our Toy Topgluon Model Coloron exchange yields KK, DD, and BB mixing quark charges under strong gauge groups are non-universal the top and bottom mass eigenstate quarks are admixtures of ordinary and heavy vector gauge eigenstate quarks Mixing among ordinary and heavy vector quarks also leads to flavor-changing b-quark decays: b! s

30 Limits on Toy Topgluon Model M C HTeVL 5 Allowed... 4 l 2 KK mixing may exclude l 2 ë LHC dijets exclude KK mixing may exclude l 2 ë 3 BB mixing and b! s exclude KK mixing certainly excludes Cotw R.S. Chivukula, EHS, N. Vignaroli (2012) in preparation Θ

31 Conclusions

32 Conclusions Physics beyond the SM may lurk in the strong interactions LHC can discover and study colorons, incorporate NLO results for the coloron K-factor and pt distribution into dijet searches use associated W+ C a production to probe the coloron s couplings. Additional coloron effects? FCNC: yes, if couplings are flavor non-universal precision EW: negligible in, Zb b top-quark asymmetry: for some coupling values