FCNC Z 0 Model and Effects in B Physics Cheng-Wei Chiang Cheng-Wei Chiang National Central University & Academia National Central University & Academia Sinica Sinica Enjoyable collaborations with: Enjoyable collaborations with: V. Barger, J. Jiang, H.-S. Lee, and P. Langacker V. Barger, J. Jiang, H.-S. Lee, and P. Langacker PLB PLB 580, 580, 186 186 (2004); (2004); 596, 596, 229 (2004); 229 (2004); 598 598 , 218 , 218 (2004). (2004). July 21- 22, 2005 Taipei Summer Institute
Transcript
FCNC Z0 Model and Effects in B PhysicsFCNC Z0 Model and Effects in B Physics
Cheng-Wei ChiangCheng-Wei ChiangNational Central University & Academia SinicaNational Central University & Academia Sinica
Cheng-Wei ChiangCheng-Wei ChiangNational Central University & Academia SinicaNational Central University & Academia Sinica
Enjoyable collaborations with:Enjoyable collaborations with:V. Barger, J. Jiang, H.-S. Lee, and P. LangackerV. Barger, J. Jiang, H.-S. Lee, and P. LangackerPLB PLB 580, 580, 186186 (2004); (2004); 596, 596, 229 (2004); 229 (2004); 598598, 218 (2004)., 218 (2004).
July 21- 22, 2005 Taipei Summer Institute
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OutlineOutline
Introduction to a FCNC Introduction to a FCNC ZZ 00 boson boson
Collider constraintsCollider constraints
Effects in low-energy effective HamiltonianEffects in low-energy effective Hamiltonian
Some Some hintshints of new physics in charmless |new physics in charmless |SS| = 1 transitions| = 1 transitions
BBss mixing mixing
SummarySummary
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Extra heavy neutral Extra heavy neutral ZZ 00 gauge bosons exist in most extensions of the gauge bosons exist in most extensions of the
Standard Model and their supersymmetric versions.Standard Model and their supersymmetric versions.
Examples include GUT’s, extra-dimensional models, string models, Examples include GUT’s, extra-dimensional models, string models, little Higgs, etc.little Higgs, etc.
The extra symmetry can forbid an elementary The extra symmetry can forbid an elementary term in SUSY, while term in SUSY, while allowing effective allowing effective and and BB terms to be generated at the U(1) terms to be generated at the U(1)00 breaking scale, providing a solution to the breaking scale, providing a solution to the problem. problem.
Accompanying with the extra symmetry are some exotic fermions to Accompanying with the extra symmetry are some exotic fermions to cancel the anomaly and at least a Higgs singlet to break the symmetry.cancel the anomaly and at least a Higgs singlet to break the symmetry.
Conclusion: for physics beyond the SM, the existence of a Conclusion: for physics beyond the SM, the existence of a ZZ 00 gauge gauge
boson is almost model-independent; only the details, such as the mass boson is almost model-independent; only the details, such as the mass and couplings, are model specific.and couplings, are model specific.
Need for a Z0 BosonNeed for a Z0 Boson
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The Fifth ForceThe Fifth Force
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In the gauge eigenbasis, the In the gauge eigenbasis, the ZZ 00 neutral current Lagrangian is given by neutral current Lagrangian is given by
In string models, it is possible to have family-nonuniversal In string models, it is possible to have family-nonuniversal ZZ 00 couplings couplings
to fermion fields due to different constructions of the different families. to fermion fields due to different constructions of the different families. [Chaudhuri et al, NPB 456, 89 (1995)][Chaudhuri et al, NPB 456, 89 (1995)]
After flavor mixing, one obtains FCNC After flavor mixing, one obtains FCNC ZZ 00 interactions (non-diagonal) interactions (non-diagonal)
in the fermion mass eigenstates, which may lead to new CP-violating in the fermion mass eigenstates, which may lead to new CP-violating effects:effects:
This may also imply flavor-violating This may also imply flavor-violating ZZ couplings if there is couplings if there is ZZ--ZZ 00
mixing.mixing.
FCNC Z0 BosonFCNC Z0 Boson
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The mass of an extra The mass of an extra ZZ 00 from the non-observation of direct production from the non-observation of direct production
((pp anti- anti-pp → → ZZ 00 → → l ll l ) at CDF (√s = 1.96 TeV) at CDF (√s = 1.96 TeV ) is found to be ≥ 670 ) is found to be ≥ 670
Direct Search at CDF Run IIDirect Search at CDF Run II
The initial LHC reach will be 2 TeV (with power to discriminate among models) and can go up to 5 TeV.
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Precision data also providePrecision data also providestringent constraints.stringent constraints.
[Erler and Langacker, [Erler and Langacker, Review of Particle Physics 2004]Review of Particle Physics 2004]
More ConstraintsMore Constraints
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The The ZZ--ZZ 00 mixing is given as mixing is given as
ZZ11 = = ZZSMSM cos cos + + ZZ 00 sin sin
ZZ22 = – = – ZZSMSM sin sin + + ZZ 00 cos cos
The mixing angle The mixing angle between between ZZ and and ZZ 00 satisfies satisfies
LEP precision measurement of coupling constants at the LEP precision measurement of coupling constants at the ZZ-pole gives-pole gives
||| < (a few) | < (a few) ££ 10 10-3-3..
[Erler and Langacker, PLB 456, 68 (1999)][Erler and Langacker, PLB 456, 68 (1999)]
This also implies a heavy This also implies a heavy ZZ 00 boson. boson.
Z-Z 0 MixingZ-Z 0 Mixing
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The sin2The sin2 measurements from various | measurements from various |SS| = 1 | = 1 BB meson decays do not meson decays do not completely agree with the measurements from the charmonium modes.completely agree with the measurements from the charmonium modes.
These inconsistencies may have the same new physics origin.These inconsistencies may have the same new physics origin.
Studies of the Studies of the K KSS mode, which has a simpler amplitude structure, mode, which has a simpler amplitude structure,
indicates that it is likely to be polluted with a new EW penguin indicates that it is likely to be polluted with a new EW penguin amplitude.amplitude.
Anomalies in Hadronicb → s q q Transitions
Anomalies in Hadronicb → s q q Transitions
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Consider the following ratios of the BR’s of Consider the following ratios of the BR’s of K K modes: modes:
RRcc and and RRnn should be the same in the SM. Possible explanations: should be the same in the SM. Possible explanations:
underestimate of underestimate of 00 detection efficiency, thus overestimating the detection efficiency, thus overestimating the BR’s of those corresponding modes;BR’s of those corresponding modes;[Gronau and Rosner, PLB [Gronau and Rosner, PLB 572572, 43 (2003)], 43 (2003)]
Isospin-violating new physics contribution to color-allowed EW Isospin-violating new physics contribution to color-allowed EW penguin amplitude.penguin amplitude.[Buras et al, PRL [Buras et al, PRL 9292, 101804 (2004); NPB , 101804 (2004); NPB 697697, 133 (2004), hep-ph/0410407], 133 (2004), hep-ph/0410407]
K AnomalyK Anomaly
2.42.4
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The effective Hamiltonian of the anti-The effective Hamiltonian of the anti-bb → anti- → anti-ss qq anti- anti-qq transitions transitions mediated by the mediated by the Z Z ' is' is
Even though the operator is suppressed by the heavy Even though the operator is suppressed by the heavy ZZ 00 mass, they can mass, they can
compete with SM loop processes because of their tree-level nature.compete with SM loop processes because of their tree-level nature.
In general, one will receive new contributions in both QCD and EW In general, one will receive new contributions in both QCD and EW penguin operators.penguin operators.
In view of the fact that the In view of the fact that the K K data can be explained with a new EW data can be explained with a new EW penguin amplitude, we assume that the penguin amplitude, we assume that the ZZ
00 mainly contributes to these mainly contributes to these operators and obtainoperators and obtain
This is possible through an This is possible through an OO(10(10-3-3) mixing angle between ) mixing angle between ZZ and and ZZ 00..
Note also that here we only include the LH coupling for the Note also that here we only include the LH coupling for the ZZ 00--bb--ss
coupling. The RH coupling can in principle be included, at the price of coupling. The RH coupling can in principle be included, at the price of more free parameters to play with.more free parameters to play with.
Low-Energy Effective Hamiltonian
Low-Energy Effective Hamiltonian
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To study the To study the K K anomaly Buras et al anomaly Buras et al introduce the ratiointroduce the ratio[PRL [PRL 92, 92, 101804 101804
(2004(2004)]]
One should note that although One should note that although cc7,87,8 play a less important role compared play a less important role compared
with with cc9,109,10 in the SM, they can receive contributions from the in the SM, they can receive contributions from the Z Z ' such that ' such that
we cannot neglect them.we cannot neglect them.
In the analysis of Buras et al, it was implicitly assumed that new physics In the analysis of Buras et al, it was implicitly assumed that new physics contributes dominantly to the (V-A) contributes dominantly to the (V-A) (V-A) EW penguins. (V-A) EW penguins.
As one of their conclusions under this assumption, As one of their conclusions under this assumption, SS K KSS will be greater will be greater
than than SS K KSS or even close to unity if one wants to explain the or even close to unity if one wants to explain the K K
anomaly.anomaly.
Some NotationsSome Notations
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Using the same hadronic inputs from Using the same hadronic inputs from modes as given by Buras et al, modes as given by Buras et al, we get two sets of solutions: (we get two sets of solutions: (qq,,) = (1.61,–84) = (1.61,–84 。。 ) and (3.04,–83) and (3.04,–83 。。 ), ), whereas they only take the small whereas they only take the small qq solution. solution.
SolutionsSolutions
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Use the following variables to parameterize our model:Use the following variables to parameterize our model:
We obtain the solutions (RH couplings included for illustration We obtain the solutions (RH couplings included for illustration purposes only):purposes only):
We We werewere able to find solutions (except for (A able to find solutions (except for (ALL)) to account for both the )) to account for both the
K K and and SS K KSS data because the contributions from the data because the contributions from the OO7,87,8 (from RH (from RH
couplings at the couplings at the ZZ 00--qq--qqbar vertices) and bar vertices) and OO9,109,10 operators interfered operators interfered
differently in these two sets of decay modes.differently in these two sets of decay modes.
Fitting with S KS TooFitting with S KS Too
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In the SM In the SM MMBBss is expected to be about 18 ps is expected to be about 18 ps-1-1 and its mixing phase and its mixing phase ss is is
only a couple of degrees.only a couple of degrees.
In contrast to the In contrast to the BBdd system, the more than 25 times larger oscillation system, the more than 25 times larger oscillation
frequency and a factor of four lower hadronization rate from frequency and a factor of four lower hadronization rate from bb quarks quarks pose the primary challenges in the study of pose the primary challenges in the study of BBss oscillation and CP oscillation and CP
asymmetries.asymmetries.
Although new physics contributions may not compete with the SM Although new physics contributions may not compete with the SM processes in most of the processes in most of the bb → → cc decays ( decays (ss less modified), they can play less modified), they can play
an important role in an important role in BBss mixing because of its loop nature in the SM. mixing because of its loop nature in the SM.
In the following, we quote the SM values:In the following, we quote the SM values:
Testable at Tevatron and LHC for Testable at Tevatron and LHC for xxss up to ~75 with error at a few % up to ~75 with error at a few %
level and level and ss//ss~0.15 with error ~0.02. Precision on sin(2~0.15 with error ~0.02. Precision on sin(2ss) depends ) depends
upon upon xxss..
Bs MixingBs Mixing
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The mixing is induced by a tree-level The mixing is induced by a tree-level ZZ 00 exchange (LH current only): exchange (LH current only):
In the particular case of a left-In the particular case of a left-chiral (right-chiral) chiral (right-chiral) ZZ ' model, ' model, one can combine the one can combine the measurements of measurements of MMss (or (or xxss) )
and sin 2and sin 2ss to determine the to determine the
coupling strength coupling strength LL ( (RR) and ) and
the weak phase the weak phase LL ( (RR) up to ) up to
discrete ambiguities.discrete ambiguities.
Once RH currents are introduced, L-R interference dominates over Once RH currents are introduced, L-R interference dominates over purely LH or RH interactions.purely LH or RH interactions.
Bs Mixing with a FCNC Z0Bs Mixing with a FCNC Z0
Barger, CWC, Jiang and Langacker, PLB 596, 229 (2004)
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Extra U(1) gauge bosons are common in many extensions of the SM.Extra U(1) gauge bosons are common in many extensions of the SM.
FCNC can be induced in models where the U(1)FCNC can be induced in models where the U(1) 00 charges are non- charges are non-
diagonal or family-nonuniversal.diagonal or family-nonuniversal.
Such models provide new CP-violating sources that may have Such models provide new CP-violating sources that may have significant effects on low-energy physics.significant effects on low-energy physics.
BR’s and CPA’s of BR’s and CPA’s of K K and and K KSS modes can be readily accounted for. modes can be readily accounted for.
Implications in Implications in BBss mixing are analyzed. mixing are analyzed.
Analysis of EDM, updated results of hadronic Analysis of EDM, updated results of hadronic BB decays along with decays along with analyses of semileptonic analyses of semileptonic BB decays are in progress.decays are in progress.
Summary and OutlookSummary and Outlook
Other slidesOther slides
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If the If the H H11 H H22 term is missing from the superpotential ( term is missing from the superpotential ( = 0), then the = 0), then the
theory presents an additional Peccei-Quinn symmetry. Under this theory presents an additional Peccei-Quinn symmetry. Under this symmetry, the Higgs superfield Hsymmetry, the Higgs superfield H11 undergoes a phase transition. When undergoes a phase transition. When
the bosonic component of Hthe bosonic component of H11 gets a non-zero vev, the PQ symmetry is gets a non-zero vev, the PQ symmetry is
broken, leading to an experimentally unacceptable Weinberg-Wilczek broken, leading to an experimentally unacceptable Weinberg-Wilczek axion. Thus, a non-vanishing axion. Thus, a non-vanishing is required to render a physically is required to render a physically acceptable theory.acceptable theory.
At least a Higgs singlet is required to break the U(1)’ symmetry. This At least a Higgs singlet is required to break the U(1)’ symmetry. This may lead to mixing between the standard Higgs doublet and the new may lead to mixing between the standard Higgs doublet and the new singlet. The LEP limit of SM-like Higgs mass (msinglet. The LEP limit of SM-like Higgs mass (mhh >= 115 GeV) does >= 115 GeV) does
not apply and a lighter Higgs is allowed.not apply and a lighter Higgs is allowed.
The neutralino sector is extended to have 6 components [MSSM: 4 and The neutralino sector is extended to have 6 components [MSSM: 4 and NMSSM: 5]. This may have significant effects on CDM.NMSSM: 5]. This may have significant effects on CDM.
Neutrinos may carry U(1)’ charges. They are Dirac fermions if they Neutrinos may carry U(1)’ charges. They are Dirac fermions if they carry such charges; otherwise, they are still Majorana.carry such charges; otherwise, they are still Majorana.
Some NotesSome Notes
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Accompanying with the extra symmetry are some exotic fermions to Accompanying with the extra symmetry are some exotic fermions to cancel the anomaly, or the anomalies are canceled by a Green-Schwarz cancel the anomaly, or the anomalies are canceled by a Green-Schwarz mechanism and at least a Higgs singlet to break the symmetry.mechanism and at least a Higgs singlet to break the symmetry.
In perturbative heterotic string models with supergravity mediated In perturbative heterotic string models with supergravity mediated symmetry breaking, the U(1)’ and EW breaking are both driven by a symmetry breaking, the U(1)’ and EW breaking are both driven by a radiative mechanism, with their scales set by the soft SUSY breaking radiative mechanism, with their scales set by the soft SUSY breaking parameters, implying that the Z’ mass should be around 1 TeV. [Cvetic parameters, implying that the Z’ mass should be around 1 TeV. [Cvetic et al, PRD 56, 2861 (1997)]et al, PRD 56, 2861 (1997)]
Radiative breaking of EW symmetry (SUGRA or GMSB) often yields Radiative breaking of EW symmetry (SUGRA or GMSB) often yields EW/TeV-scale Z’.EW/TeV-scale Z’.
In contrast to the In contrast to the BBdd system, the more than 25 times larger oscillation system, the more than 25 times larger oscillation
frequency and a factor of four lower hadronization rate from frequency and a factor of four lower hadronization rate from bb quarks quarks pose the primary challenges in the study of pose the primary challenges in the study of BBss oscillation and CP oscillation and CP
asymmetries.asymmetries.
World average World average ss//ss = 0.24 = 0.24+0.28+0.03+0.28+0.03–0.38–0.04–0.38–0.04. [hep-ex/0507084]. [hep-ex/0507084]
Some NotesSome Notes
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Bd Ks and 0 Ks (I)Bd Ks and 0 Ks (I)
CWC and Rosner, PRD CWC and Rosner, PRD 6868, 014007 (2003); Barger, CWC, Langacker, and Lee, PLB , 014007 (2003); Barger, CWC, Langacker, and Lee, PLB 580580, 186 (2004), 186 (2004)
The The K Kss mode is a loop-dominated process in SM mode is a loop-dominated process in SM (susceptible to new physics)(susceptible to new physics)::
A(A( K Kss) = p e) = p ei (i (SMSM + + pp)) + s e + s ei (i (SMSM + + ss)), , SMSM ~ arg[V ~ arg[VcbcbVVcscs**]]..
Assume new physics contributes to one of the decay amplitudes.Assume new physics contributes to one of the decay amplitudes.
||pp| can be normalized by BR(K| can be normalized by BR(K*0*0++), consistent with SM prediction.), consistent with SM prediction.
ss contains EWP, assumed to be modified by new interactions. contains EWP, assumed to be modified by new interactions.
The The 00 K Kss mode is slightly more complicated and involves color-suppressed tree mode is slightly more complicated and involves color-suppressed tree amplitude.amplitude.
1.3 / 2.7 discrepancy
2.2
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Bd Ks and 0 Ks (II)Bd Ks and 0 Ks (II)
Assume new isospin-violatingAssume new isospin-violating
CPA’s seem to favor a new CPA’s seem to favor a new
weak phase of weak phase of LL '' 100 100±± and and
||| | '' 10 10-3-3~10~10-2-2..
Z’Z’ changes the CPA’s for both changes the CPA’s for both
modes in the same direction.modes in the same direction.
Ks
0 Ks
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Basics of B FactoriesBasics of B Factories
SLAC PEPII collider using BaBar detector:SLAC PEPII collider using BaBar detector: 9.0GeV(e9.0GeV(e--) ) £ £ 3.0GeV(e3.0GeV(e++); L=6.5); L=6.5££10103333/cm/cm22/sec/sec ss L dt = 131 fb L dt = 131 fb-1-1; on resonance: 113 fb; on resonance: 113 fb-1 -1 ; 123M B anti-B pairs (2003 ; 123M B anti-B pairs (2003
summer)summer)
KEKB collider using Belle detector:KEKB collider using Belle detector: 8.0GeV(e8.0GeV(e--) ) £ £ 3.5GeV(e3.5GeV(e++); L=1.0); L=1.0££10103434/cm/cm22/sec/sec ss L dt = 158 fb L dt = 158 fb-1-1; on resonance: 140 fb; on resonance: 140 fb-1-1; 152M B anti-B pairs (2003 ; 152M B anti-B pairs (2003
summer)summer) ss L dt = 219 fb L dt = 219 fb-1-1 (3/30/2004). (3/30/2004).
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V. Barger, J. Jiang, P. Langacker, hep-ph/0405108, submitted to PLB.
