Venturing Beyond Known Physics with Top Quarks

Transcription

1 Vnturing Byond Known Physics with Top Quarks Jrnj F. Kamnik 19/07/2011, Ljubljana

2 Standard modl of fundamntal intractions

3 Standard modl of fundamntal intractions SU(3)c x SU(2)L x U(1)Y

4 Opn issus in fundamntal high nrgy physics Dynamics of lctrowak symmtry braking?? SU(3)c x SU(2)L x U(1)Y U(1)EM

5 Opn issus in fundamntal high nrgy physics Dynamics of lctrowak symmtry braking?? SU(3)c x SU(2)L x U(1)Y U(1)EM Pattrns and hirarchis in frmion masss and mixing?

6 Opn issus in fundamntal high nrgy physics Dynamics of lctrowak symmtry braking?? SU(3)c x SU(2)L x U(1)Y U(1)EM Pattrns and hirarchis in frmion masss and mixing? Particl constitunts of cosmological dark mattr?

7 Opn issus in fundamntal high nrgy physics Dynamics of lctrowak symmtry braking?? SU(3)c x SU(2)L x U(1)Y U(1)EM Pattrns and hirarchis in frmion masss and mixing? Can w addrss ths issus by studying th top quark? Particl constitunts of cosmological dark mattr?

8 Top quark within th Standard Modl Is th top quark spcial?

9 Top quark within th Standard Modl Is th top quark spcial? Havist known fundamntal frmion Scintific Amrican

10 Top quark within th Standard Modl Is th top quark spcial? Havist known fundamntal frmion particl Scintific Amrican

11 Top quark within th Standard Modl Is th top quark spcial? particl Havist known fundamntal frmion rsponsibl for largst EW quantum corrctions Scintific Amrican Largst intraction coupling in th SM snsitivity to th dynamics of th Higgs mchanism

12 Top quark within th Standard Modl Is th top quark spcial? particl Havist known fundamntal frmion rsponsibl for largst EW quantum corrctions Scintific Amrican Largst intraction coupling in th SM snsitivity to th dynamics of th Higgs mchanism

13 Top quark within th Standard Modl Is th top quark spcial? particl Havist known fundamntal frmion rsponsibl for largst EW quantum corrctions July LEP2 and Tvatron (prl.) LEP1 and SLD 68# CL m W!GV" m H!GV" m t!gv" Largst intraction coupling in th SM snsitivity to th dynamics of th Higgs mchanism Scintific Amrican

14 Could th top quark b composit?? 1 Â = 10 8 cm 1 fm = cm

15 Could th top quark b composit? Study of substructur with multipol xpansion of EM, strong and wak intractions chromo-magntic dipol momnt H ff = 1 2 ψ q (F µν σ µν )(µ q + iγ 5 d q ) +g s (G a µνt a σ µν )( µ q + iγ 5 dq ) ψ q magntic dipol momnt lctric dipol momnt chromo-lctric dipol momnt

16 Could th top quark b composit? Study of substructur with multipol xpansion of EM, strong and wak intractions chromo-magntic dipol momnt H ff = 1 2 ψ q (F µν σ µν )(µ q + iγ 5 d q ) +g s (G a µνt a σ µν )( µ q + iγ 5 dq ) ψ q magntic dipol momnt lctric dipol momnt chromo-lctric dipol momnt Will affct nuclar proprtis through quantum corrctions d t < cm d t < cm χ χ JFK, Papucci, Wilr,

17 2.0g 10.µνTh constraint from th(1) nutron LR,y s ar still poorly con- a i..µν dt mt c< Q H σ U + h.c. B, µν a clr,w g Q τ Hσ U + h.c. W, µν EDM is dominatd by th contribution to th Winbrg on top quark proprtis 2 µν with dimnsional couplings c 1/Λ In particular, i i. 85% U + h.c. which Bµν, amounts(1) to roughly of th total fof th LHC. clr,y g Q H σoprator, Im (clr,i ) = 0 would signal CP violation. fctc of d1/λ, vn though th light quark (C)EDM th top quark shows dt in2.dnin with dimnsional couplings particular, In i th following, w will mploy a phnomnological i ribution to th WindIm by(c th SM. Th lad- signal contributions ar not totally ngligibl. Furthrmor, th ) = 0 would CP violation. Hamiltonian which can b asily translatd to th mor LR,i gry blob dnots nth thin (chromo)-lctric constraint from duhg provids a (twobasis ordrs of magnitud) th following, w will mploy a phnomnological physical SU (2) (1) gaug invariant in Eq. (1), ol oprator. momnts, (C)EDM and Hamiltonian can bwakr asily translatd to mor Study ofwhich substructur with multipol xpansion of strong and wak bound on d tth, sinc it EM, is not snsitiv to th Win1 µν physical SU (2) U (1) gaug invariant basis in Eq. (1), intractions H = ψ (F σ )(µq + iγ5 dq ) wakr than dn for brg oprator and q also µν comparativly ff chromo-magntic dipol momnt 2 ario is ralizd if som th light quark CEDMs. 1 on group (RG) voa a µν µν ly composit Hff =[1]. ψ Th q (Fµν σ )(µq + iγ5 dq ) +gs (Gµν t σ )(µ q + iγ5 dq ) ψq Th indirct constraints on th othr top dipol mo2 known tomost NLLnatural accurk, is th 1 considrably a mnts a µν in Eq. (2) ar Th EDM abc µνλρ a wakr. bσ c oprator mixs into mount of compositnss +g (G t σ )(µ + iγ d ) ψ wf ε G G G, (2) s q 5 q q µν magntic dipol momnt µσ ν λρ 2 6 of thlctric top, ddipol light quark EDMs only through h compositnss scal c vrsa. Nvrtht, inducs momnt 1 abc µνλρ a bσ c 0123 DM and CEDM ar xwak εintractions and is supprssd flavormomnt facwf Gd, G G, (2) q = u, s, c, b, t and ε = 1. Wbydnot dmixing [9] that th CEDMs 6 whr chromo-lctric dipol q and µσ ν λρ 12 hin th statd rrors, w find that th nutron EDM tors [17] rsulting in d = dtq,, and d as th EDM and th CEDM of th quark whil consto th Winbrg opd q 0123 whr q = u, d, s, c, b, t and ε =qw 1.arW dq bound and othr hand, can also Will affct nuclar proprtis through quantum corrctions µ thdnot MDM quntly find acorrsponding wak of and CMDM. W nstrains th top CEDM toq and b µ td out, as shown in of This hapd q th as top. th EDM and th hav CEDM of th th quark whil Winbrg oprator [6], includd CP q,violating nrs th ar not µq of and µ d ar th corrsponding MDM and CMDM. WCorrspondingly, which will b crucial latr. w.hav q top d < cm (95% C.L.) (7) < cm (95% C.L.), (6) t t ofhav naturalnss includdand thposcp violating omittd Winbrg th trmsoprator involving[6], th chargd gaug bosons, JFK, Papucci, Wilr, latr. s.g. [4]. Th prswill b crucial Corrspondingly, w hav. which (3) sinc thy will not play an important rol in th following A strongr limit coms from b sγ and b s dt mt < Th constraint from th nutron accssibl to thirdtrms th chargd bosons, SM FIG.lswhr 1: Diagrams gnrating th contribution to th and hav bn alrady invstigatd [7]. carris Canth bth studid dirctly at high nrgy collidrs procsss, sinc th lading contribution th Momittd is dominatd byinvolving th contribution togaug th Winbrg brg oprator at th top thrshold [9]. Th gry blob n th rcnt of CP sinc thy hints will not play an important rol in th following th insrtion of th chromo-lctric dipol oprator. sam loop 85% and of flavor supprssions. Following [18], w combind ffcts of rator, which amounts to roughly th total ftxt Minimal andofhav bn Flavor alradyindications invstigatd lswhr [7]. Exprimntal of non-standard top intractions? SM Could th top quark b composit? 3 3 QED+Z+µ µ γ µ γ, Z Z γ, Z3 QED+Z+µ µ µ γ Elctrons to muons via Z γ, Z Z µ Z Elctrons to muons via Z µ µ Z µ γ 4 Z γ Z Blob diagrams χ χ SM SM 4 Blob diagrams χ χ SM SM 3 3 obtain volution to though tnt of RG d t in dn, vn th light quark (C)EDM Indirct constraints and mix undr QCD rnormalization group (RG lution. At prsnt, ths ffcts ar known to NL ro contributions also ntributions ar not totally ngligibl. Furthrmor, th our rsults for spcific racy [8]. In particular th Winbrg oprator mix 2

18 Top quark xprimnts (I): Tvatron Tvatron s Ep + Ep = 1.96 TV CDF CDF _ CDF D0!"#$!%&$'()*+$ V, A!,#)+$-.%.&-/$&)*0/#*$%1$23'()*+$ l+!"#$!%&$'()*+$! 4&-/$5$1#*6-%/7$8")*9#$:;<$ l-! =*%>(8#>$-/$&)-*.$?-)$!!"#$$%&%'#(%)$"%*"**"+,-%)$" _ Production in pp collisions )*9#$:;<$ -)$!!"#$$%&%'#(%)$"%*"**"+,-%)$"! F#8)G.$HIJ$A$DEEKL$-/$,2$ D0 $$ L$-/$,2$ 85% Discovry in *%/9$&*%>(80-%/$$ 15% 40*%/9$&*%>(80-%/$$ M%.0$&*#8-.#$&*#>-80-%/.$%1$&*%>(80-%/$8*%..$.#80-%/$$ CDF, Phys. Rv. Ltt. 74, (1995) 2G$$)&&*%N-6)0#$OO@P$8)Q8(Q)0-%/.7$&*#8-.-%/$%1$RK$0%$SKC$ D0, Phys. Rv. Ltt. 74, (1995) *#8-.#$&*#>-80-%/.$%1$&*%>(80-%/$8*%..$.#80-%/$$ -6)0#$OO@P$8)Q8(Q)0-%/.7$&*#8-.-%/$%1$RK$0%$SKC$ arxiv:

19 Top quark xprimnts (I): Tvatron Tvatron CDF s Ep + E p =1.96 TV _ D0 CDF V, A l + _ Production in pp collisions (L σ = N) l - D0 arxiv: luminosity No. vnts cross sction σ ~ ara [b = 100 fm 2 ] ~80k top quarks producd until 2011

20 Top quark production & dtction a FERMI NATIONAL ACCELERATOR LABORATORY Exprimntalists viw Artists viw Gnric signatur: (b-taggd) hadronic jts, chargd lpton(s) and missing nrgy

21 Forward-backward asymmtry in tt production [ Charg (a)symmtric cross-sction _ σ F 1 0 dσ d cos θ, d cos θ σ B 0 1 dσ d cos θ. d cos θ t P q θ q P t B F A t t FB = σ F σ B σ F + σ B

22 _ Forward-backward asymmtry in tt production θ dpndnc of lading QCD contribution at high nrgis dictatd by hlicity consrvation lik in QED + - μ + μ - : dσ d cos θ 1 + cos2 θ

23 _ Forward-backward asymmtry in tt production θ dpndnc of lading QCD contribution at high nrgis dictatd by hlicity consrvation lik in QED + - μ + μ - : dσ d cos θ 1 + cos2 θ full top quark mass dpndnc capturd by Mandlstam paramtrization ˆt = m 2 t ŝ 2 [1 β t cos θ] lading QCD contribution vn in t β t = 1 4m2 t ŝ ˆt =(p q p t ) 2 ŝ =(p t + p t) 2

24 Forward-backward asymmtry in tt production _ Non-zro AFB rquirs t-odd (or u-odd) contributions to σ In QCD inducd by quantum corrctions at ordr αs 3 q Q q Q A SM FB =0.058 ± Almida t al.,

25 _ Forward-backward asymmtry in tt production Masurmnts at th Tvatron Σ A FB Kidonakis, Ahrns t al., OO xp σ =(7.50 ± 0.48) pb A FB =0.158 ± CDF, CDF, Schwannbrgr [CDF],

26 _ Forward-backward asymmtry in tt production Masurmnts at th Tvatron Σ A FB Kidonakis, Ahrns t al., OO xp σ =(7.50 ± 0.48) pb A FB =0.158 ± High mtt rgion lss snsitiv to thrshold ffcts m t t = ŝ = (p t + p t) 2 CDF, CDF, Schwannbrgr [CDF],

27 _ Forward-backward asymmtry in tt production Masurmnts at th Tvatron Σ A FB Σ h h A FB Kidonakis, Ahrns t al., OO xp σ =(7.50 ± 0.48) pb σ h = (80 ± 37) fb σ h = σ(700gv <m t t < 800GV) A FB =0.158 ± A h FB =0.475 ± A h FB = A FB (m t t > 450GV) CDF, CDF, Schwannbrgr [CDF],

28 _ Forward-backward asymmtry in tt production Masurmnts at th Tvatron Σ A FB Σ h h A FB Kidonakis, Ahrns t al., OO xp Significant indication of nw physics! 0.0 σ =(7.50 ± 0.48) pb σ h = (80 ± 37) fb σ h = σ(700gv <m t t < 800GV) A FB =0.158 ± A h FB =0.475 ± A h FB = A FB (m t t > 450GV) CDF, CDF, Schwannbrgr [CDF],

29 Nw Physics Intrprtation(s) Non-zro AFB rquirs cosθ-odd contributions to σ 1st possibility: Quark chirality dpndnt intractions again QED + - μ + μ - analogy: M( R + L µ R µ+ L )=M( L + R µ L µ+ R ) (1 + cos θ) M( L + R µ R µ+ L )=M( R + L µ L µ+ R ) (1 cos θ) σ M 2

30 Nw Physics Intrprtation(s) Non-zro AFB rquirs cosθ-odd contributions to σ 1st possibility: Quark chirality dpndnt intractions again QED + - μ + μ - analogy: M( R + L µ R µ+ L )=M( L + R µ L µ+ R ) (1 + cos θ) M( L + R µ R µ+ L )=M( R + L µ L µ+ R ) (1 cos θ) Both QED & QCD consrv parity

31 Nw Physics Intrprtation(s) Non-zro AFB rquirs cosθ-odd contributions to σ 1st possibility: Quark chirality dpndnt intractions 2nd possibility: Intractions mdiatd in th t-channl (or u-channl) q _ q g t t _ M 1 ŝ ŝ =(p t + p t) 2

32 Nw Physics Intrprtation(s) Non-zro AFB rquirs cosθ-odd contributions to σ 1st possibility: Quark chirality dpndnt intractions 2nd possibility: Intractions mdiatd in th t-channl (or u-channl) d, s, ū, c t d, s, u, c X 1 t M 1 ˆt m 2 X ˆt =(p q p t ) 2 ˆt = m 2 t ŝ 2 [1 β t cos θ]

33 Nw Physics Intrprtation(s) Non-zro AFB rquirs cosθ-odd contributions to σ 1st possibility: Quark chirality dpndnt intractions 2nd possibility: Intractions mdiatd in th t-channl (or u-channl) d, s, ū, c t d, s, u, c X 1 t M 1 ˆt m 2 X ˆt =(p q p t ) 2 ˆt = m 2 t ŝ 2 [1 β t cos θ] W ± xchang in SM is supprssd!

34 _ tt production from top partnr dcays (3rd possibility) Prsnt σ masurmnts allow for 13% nw incohrnt contribution Σ A FB OO xp

35 _ tt production from top partnr dcays Prsnt σ masurmnts allow for 13% nw incohrnt contribution A larg asymmtric contribution can rconcil th inclusiv AFB masurmnt t q χ 0 t t q χ 0 t Production of top partnrs dcaying to top + invisibl particls Nd to pass tt slction critria and scap sarchs for tt+e miss

36 _ tt AFB from anomalous stop production Simpl(st) modl: L = L SM +(D µ t) (D µ t) m 2 t t t + χ 0 (iγ µ D µ )χ 0 m χ χ 0 cχ 0 + (Ỹq q R tχ 0 +h.c.), q=u,c,t Isidori & J.F.K., AFB gnratd via t-channl χ 0 xchang ū t t M 1 t χ 0 χ 0 χ 0 u t t

37 _ tt AFB from anomalous stop production Simpl(st) modl: L = L SM +(D µ t) (D µ t) m 2 t t t + χ 0 (iγ µ D µ )χ 0 m χ χ 0 cχ 0 + (Ỹq q R tχ 0 +h.c.), q=u,c,t Isidori & J.F.K., AFB gnratd via t-channl χ 0 xchang ~ Nd larg Br(t t χ 0 ~ ) Fix Yt=4 Both σ and AFB can b accommodatd Y ut m χ 0 =2GV m t GV

38 _ tt AFB from anomalous stop production Simpl(st) modl: L = L SM +(D µ t) (D µ t) m 2 t t t + χ 0 (iγ µ D µ )χ 0 m χ χ 0 cχ 0 + (Ỹq q R tχ 0 +h.c.), q=u,c,t Isidori & J.F.K., AFB gnratd via t-channl χ 0 xchang ~ Nd larg Br(t t χ 0 ~ ) Fix Yt=4 Both σ and AFB can b accommodatd Y ut Excl. by Σ h σ h and AFB h in som tnsion Can both b mad consistnt at 90% C.L. 1.3 Excl. by A h 1.2 m χ 0 =2GV m t GV

39 Dark Mattr Implications Standard cosmological modl

40 Dark Mattr Implications Standard cosmological modl mass-nrgy dnsity of th univrs (Ω) Rquird dark mattr proprtis no EM intraction ( dark ) non-baryonic ( big bang nuclosynthsis ) stabl - τ DM > s Ω DM h 2 =0.105 ± 0.004

41 Dark Mattr Implications DM as stabl thrmal rlic 9!: abundanc dtrmind by annihilation cross-sction 9J: Ω DM h 2 =( cm 3 /s)/σv A Wakly Intracting Massiv Particls 9,: by dimnsional analysis σ A α2 m 2 DM PLFHQ"-<B*)B coincidnc : Ω DM h for m DM 0.1 1TV

42 Γ(t uχ 0 χ 0 )= ỸtỸu 2 m 5 t 6144π 3 m 4 t Dark Mattr Implications. (12) or our illustrativ choic of paramtrs, th branching atio might rach th lvl of 10 3, which could b within h projctd LHC snsitivity [21]. Finally, stabl it is intrsting light frmions to not χ 0 that stabl frmions lik 0 with mass of a fw GV, annihilating to light quark airs via ffctiv dimnsion six oprators hav bn priously considrd mass of asa dark-mattr fw GV candidats [22]. In our as, assuming for th momnt that χ 0 is a Dirac frmion, h low-nrgy coupling of χ 0 to light quarks inducd by h t xchang annihilating lads to via ffctiv contribution L ff annih. = Ỹu 2 4m 2 t ū R γ µ u R χ 0 γ µ (1 γ 5 )χ 0. (13) n this cas th dominant contribution to th thrmal nnihilation rat of χ 0 coms from th vctor currnt art ( χ 0 γ µ χ 0 ) of th abov oprator. Using th rsults fixd by f [22], and stting m t A 200 FB GV and Ỹu 1 in (13) find that th corrct rlic abundanc of χ 0 is rproucd for m χ 0 3 GV, that would prfctly fit with th m χ 0 contributions coming from dcays of a with th lctric and color charg of top partnrs should b producd in mass slightly abov m t, and a larg ratio, whr χ 0 is a SM singlt with or lss (scaping dtction). With a p q tχ 0 ffctiv couplings, th addition in this way could account for th larg CDF. Th simpl modl w hav propos ar th only rlvant nw light sta tnt with prsnt Bltran high-nrgy t al., data a mattr candidat. Bsid a non-trivia such that t has larg couplings to bo and a vanishing coupling to χ 0 c R, thi ural and could b part of a mor am mtric xtnsion of th SM. Intrstingly, this framwork can mor dtail at th LHC. In particular of th sub-lading t uχ 0 dcay mo of th pp t t t t QCD cross-sc offr powrful tools to disproof or fin non-standard 2 GV framwork. Corrct cosmological DM abundanc can b rproducd! * Signaturs at th LHC?

43 Introducing th Larg Hadron Collidr Gnric signal of Higgslss modls is apparanc of vctor rsonancs in WW scattring p j s 2Ep =7TV WL V WL pp WZjj WL WL arxiv: p j mv [GV] Exprimnts rgistrd ~35 pb -1 of luminosity in fb -1 alrady rcordd in 2011 CMS ATLAS

44 Introducing th Larg Hadron Collidr Gnric signal of Higgslss modls is apparanc of vctor rsonancs in WW scattring p j s 2Ep =7TV WL V WL pp WZjj WL WL arxiv: p j mv [GV] Top factory : xpctd to produc 80k tt pairs pr day at nominal conditions producd ~ 10k tt _ pairs in 2010 producd ~ 200k tt pairs in 2011 CMS ATLAS

45 Prospcts for LHC discovry Gnric NP sarchs in 2 hadronic jts + missing nrgy Monotop and tt+emiss signaturs LHC snsitivity xpctd this yar xpctd dominant DM discovry channls in modls with nw chirality flipping (scalar) intractions u, c χ a) χ u, c t b) u, c S t χ t χ χ χ t Σpb tt ΧΧ 7TVLHC tt ΧΧ 14TVLHC t ΧΧ 7TVLHC JFK & Zupan, t ΧΧ 14TVLHC mgv t All intrsting mass rgion accssibl at th LHC

46 Conclusions Top quark is spcial - could b a portal to nw physics havist known fundamntal particl most strongly intracts with EWSB sctor within th SM Most significant hints of BSM physics at th Tvatron in top sctor larg FBA hints at nw top intractions at th LHC nrgy scals Exampl: light stop + nutralino; possibl implications for DM sarchs + prdicts LHC + gnric signatur: LHCb Kagan, J.F.K., Prz & Ston,