Probing B/L Violations in Extended Scalar Models at the CERN LHC A Bottom-up Approach

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1 Probing B/L Violations in Extended Scalar Models at the CERN LHC A Bottom-up Approach Kai Wang Institute for the Physics and Mathematics of the Universe the University of Tokyo Madison, 09/21/2009 J. Shu,T. Tait and KW, in preparation C. Chen, W. Klemm, V. Rentala and KW; Phys. Rev. D 79, (2009) P. Fileviez Perez, T. Han, G. Huang, T. Li and KW; Phys. Rev. D 78, (2008)

2 Testing accidental symmetries U(1) B, U(1) L in the SM: proton decay, n n oscillation, (ββ) 0ν...how about LHC? B = 2 or L = 2 n n oscillation/(ββ) 0ν decay Exotic signals: little SM background, easy to identify Possible solution to EW scale Baryogenesis (see Babu s talk) Possible connection with neutrino mass generation need to tune the parameter spaces to be accessible at the LHC (conventional models relevant to intermediate or GUT scale physics...) but not necessarily unnatural with soft breaking of symmetry(when the dimensional one parameter vanishes, the symmetry is restored.)

3 Collider-Testable B/L Violations in BSM R-parity violation in SUSY Majorana neutrino at the LHCsee T. Han and B. Zhang, 2005;Z. Si and KW,2009 tuning dimensionless Yukawa coupling;tiny Mixing highly suppressed production (require W R,Z B L to enhance production) ψ c f ψ f φ in extended scalar models (ψ f ψ f φ always m f ) Gauge interaction production with only Resonance B/ L Decay

4 Bottom-up setup Color Sextet Scalars under SU(3) C SU(2) L U(1) Y : SU(2) L adjoint 6 : (6, 3, 1/3) SU(2) L singlet Φ 6 : (6, 1, 4/3), φ 6 : (6, 1, 2/3), δ 6 : (6, 1, +1/3) Scalar QCD Tr[(D µ 6 ) (D µ 6 )] M Tr[ 2 6 6] + f Q T LC 1 τ 2 6 Q L + (D µ Φ 6 ) (D µ Φ 6 ) MΦΦ 2 6 Φ 6 + f Φ u T RC 1 u R Φ 6 + (D µ φ 6 ) (D µ φ 6 ) Mφφ 2 6 φ 6 + f φ d T RC 1 d R φ 6 + (D µ δ 6 ) (D µ δ 6 ) Mδ 2 6 δ 6 δ 6 + f δ d T RC 1 u R δ 6 + V Non-zero VEV would break U(1) EM. D µ = µ ig s G a µt a r

5 QCD Production of Color Sextet Scalar Pair 6 6 = g(p 1) + g(p 2) Φ 6(k 1) + Φ 6(k 2) t ttt q(p 1) + q(p 2) Φ 6(k 1) + Φ 6(k 2) t ttt σ(pb) M _R (GeV) Production of Φ 6Φ 6 at the LHC and Tevatron µ F = µ R = ŝ/2, CTEQ6L

6 σ(q q Φ 6Φ 6) = πc(3)c(r) d8 αs 2 d 2 3 3s β3 = 10π 27s α2 sβ 3 σ(gg Φ 6Φ 6) = d RC 2(R)π α2 s 6s where s is the total energy, β = 1 [3β(3 5β 2 ) 12C 2(R)β(β 2 2) d ln β + 1 β 1 (6C2(R)(β4 1) 9(β 2 1) 2 ] = 5π 96s α2 s[β(89 55β 2 ) + ln β + 1 β 1 (11β4 + 18β 2 29)] normalization factor C and Casimir C 2 as q 1 4M 2 Φ 6 /s and R is 6 with the d R C(R) 1/2 5/2 3 C 2(R) 4/3 10/3 3 Table: Normalization factor C(R) and quadratic Casimir C 2 (R) for d R = 3, 6, 8 under SU(3).

7 Remarks qq Φ 6 from f 11 or f 22 (valence u quark, LHC is a pp machine) ψ c ψφ, the coupling f ij irrelevant to fermion masses tree level D 0 D 0 mixing from f 11 f 22, maybe dominant decaying into top GIM violation. But only coupling to righthanded states. 3 3 = 6 3 Squark pair production with R-parity violation decay? only u c d c d c Sextet Quarks in ETC

8 Same Sign Top pp Φ 6 Φ 6 tt t t 4b + l ± l ± + E T + Nj, (No radiation included, PYTHIA shower for 3 diquark only)

9 Reconstructed two hadronic Top shows the scalar feature. Multijet resonance

10 (background included irreducible only, leading background: t tw ± )

11 Top A FB at Tevatron σ(t t) CDF = 7.50 ± 0.31 stat. ± 0.34 syst. ± 0.15 z.th. pb m t = GeV, 4.6fb 1 A t FB (SM) = 0.051; At FB = ± stat. ± syst. (m t = GeV, 3.2fb 1 ) A FB t 0.2 A FB t α M φ (GeV)

12 Color Sextet/Triplet Scalars in t-channel σ(pp tt )(pb) A FB t M φ (GeV) M φ (GeV)

13 Lepton Number Violation under SU(3) C SU(2) L U(1) Y : SU(2) L adjoint : (1, 3, 1) SU(2) L singlet φ : (1, 1, 2) Tr[(D µ ) (D µ )] M 2 Tr[ ] + y ν l T LC 1 τ 2 l L + (D µ φ) (D µ φ) M 2 Φφ φ + ye T RC 1 e R φ ++ + V

14 Production of Triplet Higgses q(p 1) + q(p 2) H ++ (k 1) + H (k 2) q(p 1) + q (p 2) H ++ (k 1) + H (k 2) q(p 1) + q (p 2) H + (k 1) + H 2(k 2) Tree Level Cross-section of Triplet Higgses Production

15 Remarks on Production triplet vev v suppresion phase space suppression t-channel W (Longitutinal dominant), cancellation with full gauge invariant set, due to Equivalence Principle (Ward Identity in spontaneous symmetry breaking case)

16 Remarks on Production (continued) QCD correction for this mass range 25% Muhlleitner and Spira, 03 real photon emission (γγ H ++ H ) 10% σ(fb) 10 2 σ(fb) M ++ H (GeV) M H ++ (GeV) T. Han, B. Mukhopadhyaya, Z. Si and KW, 2007

17 Photon-Photon σ γγ = σ elastic + σ inelastic + σ semi elastic σ elastic = σ inelastic = σ semi elastic = Z 1 Z 1 dz 1 dz 2 f γ/p (z 1 )f γ/p (z 2 )σ(γγ H ++ H ) τ τ/z 1 Z 1 Z 1 Z 1 Z 1 dx 1 dx 2 dz 1 τ τ/x 1 τ/x 1 /x 2 τ/x 1 /x 2 /z 1 dz 2 f q(x 1 )f q (x 2)f γ/q (z 1 )f γ/q (z 2 )σ(γγ H ++ H ) Z 1 Z 1 Z 1 dx 1 dz 1 dz 2 f q(x 1 )f γ/q (z 1 )f γ/p (z 2 )σ(γγ H ++ H ) τ τ/x 1 τ/x 1 /z 1 τ = 4m2 S Drees, Godbole 94

18 Another Example for Multijet + l ± l ± + E T H ++ W + W + : v pp H ++ H W + W + W W l ± l ± + E T + 4j σ(fb) BR(H ++ W + W + ) M H ++ (GeV) M H : boosted hadronic W, W -jet M ++ H (GeV) Heavy T. Han, B. Mukhopadhyaya, Z. Si and KW, 2007

19 Search via Leptonic Decays Small vev limit v < 10 4 GeV All LNV, but not observable except for H ++ H ++ l + l + ; H + l + ν l ; H 2 νν µ,e and τ respectively H 2 invisible and always produced via H ± H 2, another missing ν from H +, impossible to reconstruct. High p T event, e is better than µ pp H ++ H l + l + l ν, l + l + τ ν (l = e, µ) pp H ++ H l + l + l l, l + l + τ τ (l = e, µ)

20 SM background Four Lepton (no τ final state) SM Background if there exists same flavor, opposite sign dilepton ZZ/γ l + l l + l Veto events of M l + l M Z < 15 GeV After reconstruction, purely event counting Trilepton (no τ final state) SM Background if there exists same flavor, opposite sign dilepton W ± Z/γ l ± νl + l, W ± W ± W l ± l + l + E T Veto events of M l + l M Z > 15 GeV

21 Trilepton M T = (E l T + E T ) 2 ( p l + p) 2 T

22 τ Leptonic decay H + τν l + E T H + l + E T Lepton p T l from H + Jaccobian Peak around M H /2 (may change due to boost) l from τ, purely boost effect, much softer p l T selection (GeV) l misidentification rate 2.9% 9.4% 17.6% 4.6% 12.4% 22.2% τ survival probability 57.0% 69.8% 78.8% 62.8% 75.7% 83.7% τ selection: p T < 100 GeV (for M + H = 300 GeV) p T < 200 GeV for M + H = 600 GeV

23 τ Reconstruction No other E T in final state: pp H ++ H l + l + τ τ, l + l + µ τ, l + τ + τ τ Highly Boosted τ p invisible = κ p l ; each τ corresponds to one unknown Σ p invisible T = p T 2 independent equations M l + l + = M rec τ τ ; 1 more equation UPTO THREE τs

24 µµττ and µµµτ

25 Examples of Theory Realization Pati-Salam Model to Left-Right Model SU(2) L SU(2) R SU(4) C SU(2) L SU(2) R U(1) B L SU(3) C (3, 1, 10) : {(3, 1, 2, 1) (3, 1, 2/3, 3) (3, 1, 2/3, 6)} + L R B = 2 n n neutron anti-neutron oscillation why light? Pati-Salam (Chacko-Mohapatra, 99), Post-Sphelaron Baryogenesis and still consistent with n n constraints Neutrino mass: (3, 1, 2, 1) : l T C 1 iτ 2 l

26 Neutrino Mass and LNV SU(2) L singlet: Zee-Babu Model (two-loop neutrino mass) SU(2) L Triplet: Type-II seesaw = 1 ( ) H + 2H H 0 H + Breaking U(1) B L y ν l T LCiσ 2 l + µh T iσ 2 H + h.c m ν = y ν v = y ν µ v2 0 2M 2 If y ν is of O(0.01), µ 1keV. lim µ 0, U(1) L or U(1) B L is restored. can be naturally small. ρ-parameter prefers small µ. (Gunion et al, 90)

27 Neutrino and Triplet Leptonic Decay ( Y ν l T δ C iσ 2 l + h.c., where = + / 2 δ ++ δ 0 δ + / 2 ) No Majorana Phases sin θ 23

28 Doubly Charged (continued)

29 Majorana Phase Singly Charged Higgs BR is independent of Majorana phases.

30 Singly Charged

31 Majorana Phase: a close look m diag ν Γ + = cos θ + V P MNS, Γ ++ = V P MNS m diag ν V P MNS v 2 v 0 B V P MNS Y j + = 3X Γ ij + 2 v, 2 Y ++ = 2v Γ ++ i=1 c 12 c 13 c 13 s 12 e iδ s 13 c 12 s 13 s 23 e iδ c 23 s 12 c 12 c 23 e iδ s 12 s 13 s 23 c 13 s 23 s 12 s 23 e iδ c 12 c 23 s 13 c 23 s 12 s 13 e iδ c 12 s 23 c 13 c 23 1 C A diag(e iφ 1 /2, 1, e iφ 2 /2 )

32 Distinguish Spectrum via LNV Higgs Decay

33 Summary We discuss testing the B/L violations in the extended scalar models with the following two examples: Color sextet scalar that decays into same-sign diquark. We use the Φ tt to test its sextet nature and we plan to use the angular correlation in top decay to confirm the sextet only couples to the righthanded states. SU(2) triplet Higgs in Type-II seesaw for neutrino mass generation. H ++ l + l + is crucial in testing the model but the H + l + ν helps to link the triplet Higgs decays with the neutrino mass spectrum even in the presence of Majorana phase. Thank you.