Implications of D 0 -D 0 mixing for New Physics Alexey A. Petrov - PowerPoint PPT Presentation

Implications of D 0 -D 0 mixing for New Physics Alexey A. Petrov Wayne State University Table of Contents: • Introduction • New Physics contributions in charm mixing • Δ C=1 operators • Δ C=2 operators • Conclusions and outlook Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008

Introduction: identifying New Physics “Inverse LHC problem” The LHC ring is 27km in circumference How can KEK OR other older machines help with New Physics searches? Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 18

Introduction: charm and New Physics Charm transitions serve as excellent probes of New Physics Unique access to up-quark sector 1. Processes forbidden in the Standard Model to all orders Examples: D 0 → p + π − ν 2. Processes forbidden in the Standard Model at tree level 0 , D 0 → X γ , D → X ν ¯ Examples: D 0 − D ν 3. Processes allowed in the Standard Model Examples: relations, valid in the SM, but not necessarily in general CKM triangle relations Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 17

Introduction: charm and New Physics Charm transitions serve as excellent probes of New Physics Unique access to up-quark sector 1. Processes forbidden in the Standard Model to all orders Examples: D 0 → p + π − ν 2. Processes forbidden in the Standard Model at tree level 0 , D 0 → X γ , D → X ν ¯ Examples: D 0 − D ν 3. Processes allowed in the Standard Model Examples: relations, valid in the SM, but not necessarily in general CKM triangle relations Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 17

Recent experimental results • BaBar, Belle and CDF results D = (0 . 85 ± 0 . 76) · 10 − 2 y ′ (CDF) Belle Dalitz plot result (D 0 → K S π + π - ) • • Preliminary HFAG numbers Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 16

Introduction: why do we care? mixing mixing • intermediate down-type quarks • intermediate up-type quarks • SM: b-quark contribution is • SM: t-quark contribution is negligible due to V cd V ub dominant * • • (expected to be large) (zero in the SU(3) limit) Falk, Grossman, Ligeti, and A.A.P. Phys.Rev. D65, 054034, 2002 2 nd order effect!!! 1. Sensitive to long distance QCD 1. Computable in QCD (*) 2. Small in the SM: New Physics! 2. Large in the SM: CKM! (must know SM x and y) (*) up to matrix elements of 4-quark operators Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 15

Standard Model predictions ★ Predictions of x and y in the SM are complicated - second order in flavor SU(3) breaking - m c is not quite large enough for OPE - x, y << 10 -3 (“short-distance”) - x, y ~ 10 -2 (“long-distance”) ★ Short distance: - assume m c is large - combined m s , 1/m c , a s expansions - leading order: m s2 , 1/m c6 ! H. Georgi, … I. Bigi, N. Uraltsev ★ Long distance: - assume m c is NOT large - sum of large numbers with alternating signs, SU(3) forces zero! - multiparticle intermediate states dominate J. Donoghue et. al. P. Colangelo et. al. A.F., Y.G., Z.L., Y.N. and A.A.P. Phys.Rev. D69, 114021, 2004 Resume: a contribution to x and y of the order of 1% is natural in the SM Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 14

How New Physics affects x and y  Local Δ C=2 piece of the mass matrix affects x:  Double insertion of Δ C=1 affects x and y: Amplitude Suppose Example: phase space Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 13

How New Physics affects x and y  Local Δ C=2 piece of the mass matrix affects x: µ ∼ 1 GeV µ ∼ 1 TeV  Double insertion of Δ C=1 affects x and y: Amplitude Suppose Example: phase space Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 13

How New Physics affects x and y  Local Δ C=2 piece of the mass matrix affects x:  Double insertion of Δ C=1 affects x and y: Amplitude Suppose Example: phase space Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 13

How New Physics affects x and y  Local Δ C=2 piece of the mass matrix affects x:  Double insertion of Δ C=1 affects x and y: Amplitude Suppose Example: Zero in the SU(3) limit phase space Falk, Grossman, Ligeti, and A.A.P. Phys.Rev. D65, 054034, 2002 2 nd order effect!!! Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 13

How New Physics affects x and y  Local Δ C=2 piece of the mass matrix affects x:  Double insertion of Δ C=1 affects x and y: Amplitude Suppose Example: Zero in the SU(3) limit Can be significant!!! phase space Falk, Grossman, Ligeti, and A.A.P. Phys.Rev. D65, 054034, 2002 2 nd order effect!!! Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 13

Global Analysis of New Physics: Δ C=1 E. Golowich, S. Pakvasa, A.A.P. Phys. Rev. Lett. 98, 181801, 2007  Let’s write the most general Δ C=1 Hamiltonian Only light on-shell (propagating) quarks affect ΔΓ : with and This is the master formula for NP contribution to lifetime differences in heavy mesons Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 12

Global Analysis of New Physics: Δ C=1  Some examples of New Physics contributions E. Golowich, S. Pakvasa, A.A.P. Phys. Rev. Lett. 98, 181801, 2007 A.A.P. and G. Yeghiyan Phys. Rev. D77, 034018 (2008) For considered models, the results are smaller than observed mixing rates Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 11

Global Analysis of New Physics: Δ C=2  Multitude of various models of New Physics can affect x Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 10

Global Analysis of New Physics: Δ C=2 E.Golowich, J. Hewett, S. Pakvasa and A.A.P. Phys. Rev. D76:095009, 2007  Let’s write the most general Δ C=2 Hamiltonian … with the following set of 8 independent operators… RG-running relate C i ( m ) at NP scale to the scale of m ~ 1 GeV, where ME are computed (on the lattice) Each model of New Physics provides unique matching condition for C i ( L NP ) Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 9

New Physics in x: lots of extras E.Golowich, J. Hewett, S. Pakvasa and A.A.P. Phys. Rev. D76:095009, 2007 New Physics contributions do not suffer from QCD uncertainties as much as SM contributions since they are short-distance dominated.  Extra gauge bosons Left-right models, horizontal symmetries, etc.  Extra scalars Two-Higgs doublet models, leptoquarks, Higgsless, etc.  Extra fermions 4 th generation, vector-like quarks, little Higgs, etc.  Extra dimensions Universal extra dimensions, split fermions, warped ED, etc.  Extra symmetries SUSY: MSSM, alignment models, split SUSY, etc. Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 8

New Physics in x: lots of extras E.Golowich, J. Hewett, S. Pakvasa and A.A.P. Phys. Rev. D76:095009, 2007 New Physics contributions do not suffer from QCD uncertainties as much as SM contributions since they are short-distance dominated.  Extra gauge bosons Left-right models, horizontal symmetries, etc.  Extra scalars Two-Higgs doublet models, leptoquarks, Higgsless, etc.  Extra fermions 4 th generation, vector-like quarks, little Higgs, etc.  Extra dimensions Universal extra dimensions, split fermions, warped ED, etc.  Extra symmetries SUSY: MSSM, alignment models, split SUSY, etc. Total: 21 models considered Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 8

Dealing with New Physics-I  Consider an example: FCNC Z 0 -boson appears in models with extra vector-like quarks little Higgs models 1. Integrate out Z: for µ < M Z get 2. Perform RG running to µ ~ m c (in general: operator mixing) 3. Compute relevant matrix elements and x D 4. Assume no SM - get an upper bound on NP model parameters (coupling) Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 7

Dealing with New Physics - II  Consider another example: warped extra dimensions FCNC couplings via KK gluons 1. Integrate out KK excitations, drop all but the lightest H RS = 2 π kr c g 2 s ( C 1 ( M n ) Q 1 + C 2 ( M n ) Q 2 + C 6 ( M n ) Q 6 ) 3 M 2 1 2. Perform RG running to µ ~ m c g 2 s H RS = ( C 1 ( m c ) Q 1 + C 2 ( m c ) Q 2 + C 3 ( m c ) Q 3 + C 6 ( m c ) Q 6 ) 3 M 2 1 3. Compute relevant matrix elements and x D g 2 f 2 D B D M D � 2 3[ C 1 ( m c ) + C 6 ( m c )] − 1 6 C 2 ( m c ) − 5 � x ( RS ) s = 12 C 3 ( m c ) D 3 M 2 Γ D 1 Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 7

Dealing with New Physics - II  Consider another example: warped extra dimensions FCNC couplings via KK gluons 1. Integrate out KK excitations, drop all but the lightest H RS = 2 π kr c g 2 s ( C 1 ( M n ) Q 1 + C 2 ( M n ) Q 2 + C 6 ( M n ) Q 6 ) 3 M 2 1 2. Perform RG running to µ ~ m c g 2 s H RS = ( C 1 ( m c ) Q 1 + C 2 ( m c ) Q 2 + C 3 ( m c ) Q 3 + C 6 ( m c ) Q 6 ) 3 M 2 1 3. Compute relevant matrix elements and x D g 2 f 2 D B D M D � 2 3[ C 1 ( m c ) + C 6 ( m c )] − 1 6 C 2 ( m c ) − 5 � x ( RS ) s = 12 C 3 ( m c ) D 3 M 2 Γ D 1 Implies: M 1KKg > 3.5 TeV! Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 7

New Physics in x: extra fermions Fourth generation  Vector-like quarks (Q=+2/3)  Vector-like quarks (Q=-1/3)  Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 6

New Physics in x: extra vector bosons Generic Z’ models  Family symmetry  Vector leptoquarks  Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 5

New Physics in x: extra scalars 2-Higgs doublet model  Flavor-changing neutral Higgs  Higgsless models  Alexey A Petrov (WSU) Moriond-2008, March 1-8 2008 4