d 0 mixing @ superbelle

B. Golob, Ljubljana Univ. D0 Oscillations 1 SuperBelle, KEK, Dec 2008

B. GolobUniversity of Ljubljana,Jožef Stefan Institute

&Belle Collaboration

D0 Mixing@ SuperBelle

University of Ljubljana

“Jožef Stefan” Institute

Outline1. CP states2. Wrong sign (non-CP)3. t-dependent Dalitz4. Average5. Constraints on NP6. Prospects & Summary


1. D0 →KK/ Decays to CP eigenstates

K+K-/+-

and K-+ratio

1st evidence for D0 mixing

+

)%25.032.031.1( CPyBelle, PRL 98, 211803 (2007), 540fb-1

BaBar, arXiv:0712.2249, 384fb-1

=

)%13.039.024.1( CPy

D0 → K+K- / +-, CP even

no CPV: CP|D1> = |D1> =1/1;K-+: mixture of CP states =f(1/1,1/2)

yxA

y

KK

Ky

CPVno

M

CP

sin2

cos

1)(

)(S. Bergman et al., PLB486, 418 (2000)


1. D0 →KK/ Decays to CP eigenstates

0sincos2

)()(

)()(

)()(

)()(

00

00

00

00

CPVno

M

intmixfdec

fCP

xyA

KKDKKD

KKDKKDA

aaafDfD

fDfDA

)%08.036.026.0( A

)%15.030.001.0( A

BaBar, arXiv:0712.2249, 384fb-1

t-dependentBelle, PRL 98, 211803 (2007), 540fb-1

Belle, arXiv:0807.0148, 540fb-1

t-integrated ACP

meas =A + AFB + ACP

f

A : comparison of tagged/untagged

(D*+ →D0+),D0 →K-+ AFB: asymmetric f(cosCMS)

)%13.034.000.0( KKCPA

)%11.030.043.0( KKCPA

ACPKK ACP

AFBKK AFB

|cosCMS| |cosCMS|

|cosCMS||cosCMS|

BaBar, PRL 100, 061803 (2007),

386fb-1


D0 →KK/ Systematics breakdown

22

0

2 %10.0/

%39.0

LLyCP

22

0

2 %06.0/

%33.0

LLA

L0=540 fb-1

Belle, PRL 98, 211803 (2007), 540fb-1

largest contributions (yCP):acceptance: 0.12% scalingequal t0 assumption: 0.14% scalingbkg signal/sideband diff.: 0.09% non-scalingvariation of select.: 0.11% scalingtotal: 0.25%non-scaling: 0.10%

scalingnon-scaling

A stat.

A binning

total:non-scaling: 0.06%

0.09%0.05%0.33%

largest contrib. (ACPKK):

22

0

2 %06.0/

%32.0

LLACP


D0 →KK/ Projected sensitivity

22

0

2 %10.0/

%39.0

LLyCP

22

0

2 %06.0/

%33.0

LLA

L0=540 fb-1

(yCP)[%]

(A)[%]

L [ab-1]

16 ab-1

8 ab-1

x ab-1 stat=syst


2. D0 →KWS decays (non-CP)

D*+ → D0 slow+ D0 → D0 → K+ -

DCS decays interference;

t

mixinterf

D

DCS

D etyx

tyRR

tDK

2

22

.

20

4

'''

)(

sincos'

sincos'

xyy

yxx

t-dependence to separate DCS/mixed

BaBar, PRL 98, 211802 (2007), 384fb-1

1st evidence for D0 mixing

1

3

5

likelihoodcontours

3.9

Belle, PRL 96, 151801 (2006), 400fb-1

: unknown strong phase DCS/CF

3.8 1

3

CDF, PRL 100, 121802 (2008), 1.5fb-1

)%31.044.097.0('10)21.030.022.0(' 32

yx

)%06.0('

10)18.0('

39.040.0

23.021.0 32

y

x

)%76.085.0('10)35.012.0(' 32

yx

likelihoodcontours

95% FC confidence region


largest contrib.: x’2, y’ [stat] +0.3 -0.2 p* variation ±0.2 ±0.2 fixed decay-t parameters +0.2 -0.2 t effect on fractions ±0.3 ±0.3 total scaling ±0.5 ±0.5 total ±0.4 ±0.4 non-scaling

D0 →K

scales with data/MC

23

2

0

322' 1009.0

/

1023.0

LLx 2

2

0

2' %16.0

/

%42.0

LLy

L0=400 fb-1

scales with data

statisyst m 2/12

syst ≈ 0.5 stat

scales with data

22

0

2 %7.1/

%4.4

LLAD assumed same fraction of scaling/non-scaling

systematics as for x’2

Belle, PRL 96, 151801 (2006), 400fb-1

Systematics breakdown


D0 →K

L0=400 fb-1

(x’2) [10-3]

(y’) [%]

L [ab-1]

Projected sensitivity

23

2

0

322' 1009.0

/

1023.0

LLx

22

0

2' %16.0

/

%42.0

LLy

22

0

2 %7.1/

%4.4

LLAD

x ab-1 stat=syst


3. D0 →KSt-dependent Dalitz analyses different types of interm. states; CF: D0 → K*-+

DCS: D0 → K*+-

CP: D0 → 0 KS

if f = f populate same Dalitz plot; relative phases determined (unlike D0 → K+-);

t-dependence: regions of Dalitz plane → specific t dependence f(x, y);

titi

titi

S

eemmp

q

eemm

tDKtmm

21

21

),(2

1

),(2

1

)(),,(

22

22

022

A

A

M

1,2=f(x,y);

D0 →KS +-

access directly

x, y

D0→f

D0→f

rad

pq

yx

)09.024.0(

86.0/

30.028.0

09.010.0

29.030.0

14.010.016.013.0

)%24.033.0()%29.080.0(

Belle, PRL 99, 131803 (2007), 540fb-1

D0 →KS +-

most accurate x


largest model dependence [10-4]: x y -10.4 +0.1 K* DCS/CF + 6.9 -2.7 -5.1 -4.3 (q2) const.--------------------------------- +10 +6 Total model dep. -14 -8

experimental (major sources): x y +7.6 -7.8 p* variation -5.6 -5.7 Dalitz pdf for bkg. from different t bins ----------------------- +9 +8 Total experimental -7 -12

D0 →KS

better underst. of DCS/CF;arbitrary ½ of uncertainty takenas scaling;all other model dependencenon-scaling

±10 ± 7 model non-scaling

all scaling

±10 ±7 total non-scaling

22

0

2 %10.0/

%31.0

LLx

22

0

2 %07.0/

%26.0

LLy

L0=540 fb-1

Belle, PRL 99, 131803 (2007), 540fb-1 Systematics breakdown


model dependence: |q/p| [rad] ±0.08 ±0.06

experimental: |q/p| [rad] +0.06 +0.06 p* variation +0.03 -0.05 bkg. decay t parameters

D0 →KS

±0.08 ±0.06 model non-scaling

scales with data/MC

±0.08 ±0.06 total non-scaling

22

0

2|/| 08.0

/

30.0

LLpq 2

2

0

2 06.0/

30.0rad

rad

LL

L0=540 fb-1

scales with data/MC



D0 →KS

22

0

2|/| 08.0

/

30.0

LLpq

22

0

2 06.0/

30.0rad

rad

LL

L0=540 fb-1

(x) [%](y) [%](|q/p|)() [rad]

L [ab-1]

22

0

2 %10.0/

%31.0

LLx

22

0

2 %07.0/

%26.0

LLy

Projected sensitivity

7 ab-1

7 ab-1

13 ab-1

x ab-1 stat=syst


4. Average HFAG 2 fit

)%8.01.0(049.0004.0

054.0894.0

)%003.0336.0(9.46.24

)%064.0813.0()%095.0832.0(

D

D

K

Arad

p

qR

yx

1, 2, 3 @ 50 ab-1

E. Barberio et al. (HFAG), arXiv:0808.1297& http://www.slac.stanford.edu/xorg/hfag/

50 ab-1

only KK/, K and Ks projected sensitivities included


Average

)%8.01.0(049.0004.0

054.0894.0

)%003.0336.0(9.46.24

)%064.0813.0()%095.0832.0(

D

D

K

Arad

p

qR

yx

HFAG 2 fit

E. Barberio et al. (HFAG), arXiv:0808.1297& http://www.slac.stanford.edu/xorg/hfag/

1, 2, 3 @ 50 ab-1

50 ab-1

only KK/, K and Ks projected sensitivities included


5. Constraints on NP constraints from mixing

existing constraints already now greatly improved for many NP models; example of R SUSY:

E. Golowich et al., PRD76, 095009 (2007)

D0 D0iL

l~

iLl~

kRd

kRd

D0 D0iL

l kRd~

iLl

kRd~

|x|

R couplings R couplings

kRd

m~

[GeV]

50 ab-1

50 ab-1


Constraints on NP

constraints from CPV: SCS decays (probing penguins); small in SM, small DCPV;

SUSY: squark-gluino loops;

CF: c → sdu (K-+)SCS: c → qqu (q=s, K+K-)DCS: c → dsu (K+-)

c uW±

d, s, bVcq Vuq

g q

q

Y. Grossman et al., PRD75, 036008 (2007)

values of ˜m and m(g˜ ) for whichrf=1%

constraint from mixing|M12|

m(g˜ )

contrib. to C=1 enhancedcompared to C=2 by m(g˜ )/mc

sensitivity of mixing to this contrib. small compared to sensitivity of af

dir

SMf

NPff

ffffdir

fdirCP

AAr

raaAA

/

sinsin2


Constraints on NP

constraints from CPV: squark-gluino loops contribution

)%34.011.0(sinsin2

fff

fdir ra

Belle, arXiv:0807.0148, 540fb-1

BaBar, arXiv:0712.2249, 384fb-1

Belle, PRL 98, 211803 (2007), 540fb-1

BaBar, PRL 100, 061803 (2007), 386fb-1

if f, f O(1)all shown values excluded (rf=1%)

Y. Grossman et al., PRD75, 036008 (2007)

m(g˜ )50 ab-1: (adir

KK)=0.10%

mmLRuc

~/2~~

values of ˜m and m(g˜ ) for whichrf=1%

constraint from mixing


Notes

@50 ab-1: (x), (y) 0.05-0.1%, (|q/p|), () 0.05, (AD) 0.5-1%

most D0 oscillation studies systematics dominated need very detailed studies detector induced charge asymm. decay t bias (detector alignment) ...

obtaining stringent constraints on NP models, useful to identify possible NP signals from LHC

CPV parameters sensitivity not over full SM range more modes (KsKK, 0,....) common systematics (Dalitz models)


Super charm factorySummary on D0 mixing at Super charm factory, Novosibirsk

Super-B factory at initial stage (x), (y) ~ O( 0.1%) (ACP) ~ O(0.1%); K precisely determined from combination of measurements;

RM, y @ charm factory of lower accuracy than @ B factory (unless t-dependent meas. with asymmetric collider);

various options for CPV; several competitive or better, and complementary to B-factory (including D0D0 with C=+1); many other possibilities (Dalitz studies, triple product correlations, T-odd moments, ...)


Phenomenology bckup

DCPV in SCS decays to CP states:

)(

)(

1

1

CPfCPf

CP

TCPf

CPCP

CPfCPf

CP

TCPf

CPCP

i

f

iTff

i

f

iTff

ereAA

ereAA

ffffdir

fdirCP

fdirintmixCP

intmix

raaAA

aaaAaaA

sinsin2

)(

O(10-2) contrib. of adirf

M12 for D0:

2

22

12 12

12 y

xAxM MD

G. Raz, PRD66, 057502 (2002)


Mass insertions bckup

mass insertion approxim. (MIA): replace sum over all possible internal propagators and mixing at the vertices, with a single off-diagonal mass insertion in basis where all gauge couplings are diagonal; MIA: Taylor expanssion in mass-squared differences between intermediate particles w.r.t. chosen mass m;

example: SUSY contrib. to K0 mixing

dj

nm

nj

dj

di

mi

dimn

K

ii

nm

nj

mimnjig

jigdj

dj

di

di

K

ZmZZmZCM

mmm

mmCmmmJ

mmmJZZZZM

1,

221

2212

222,

222224

2224121212

)~()~(

~~~

)~()~()~,~,~(

)~,~,~(

mixing anglesqq ~


D0 →KK/bckup

scales with MCbetter detect. (MC) desc.

scales with data/MCscales with data/MCscales with data/MC

total non-scaling 0.10% 0.06%


22

0

2 %10.0/

%39.0

LLyCP 2

2

0

2 %06.0/

%33.0

LLA L0=540 fb-1

Belle, PRL 98, 211803 (2007), 540fb-1


D0 →KK/bckup

scales with data


22

0

2 %06.0/

%32.0

LLACP L0=540 fb-1

q shape difference D0/D0

bkg. side/signal windowrnd s bkg.

A stat.

A binning

fit binning3/4 layer SVD

0.02%0.01%0.03%

0.09%0.05%

0.03%0.01%

source (ACPKK) Belle, arXiv:0807.0148, 540fb-1


D0 →KK/bckup Systematics breakdown

Belle, PRL 98, 211803 (2007), 540fb-1

acceptance: fit generated t for selected evts.; constant within MC stat.equal t0: t0 diff KK/K/ from MC, including missaligned SVD; equal within MC stat.diff. bkg. signal/sideband:

)min()min(:

,:

,:11

)1(0

)1()(

'

'

0

0

bbsbsbss

sbsbsbsbs

bbbbs

sb

s

bss

bsss

ppselectionsideband

ttptsideband

ttptwindowsignalpp

p

tptt

tptpt

diff. for various sidebands → syst.


model dependence [10-4]: x y -10.3 +0.1 K*0(1430) DCS/CF -15% + 6.9 -2.5 K*2(1430) DCS/CF -30% -1.6 -0.9 K*(1410) DCS & CF -20%--------------------------------- +10 +6 Total model dep. -14 -8

experimental (major sources): x y +7.6 -7.8 p* variation -5.6 -5.7 Dalitz pdf for bkg. from different t bins ----------------------- +9 +8 Total experimental -7 -12

D0 →KSbckup

better underst. of DCS/CF;arbitrary ½ of uncertainty takenas scaling;all other model dependencenon-scaling

±10 ± 7 model non-scaling

scales with data/MC

all scaling

±10 ±7 total non-scaling

22

0

2 %10.0/

%31.0

LLx

22

0

2 %07.0/

%26.0

LLy

L0=540 fb-1

Belle, PRL 99, 131803 (2007), 540fb-1 Systematics breakdown


D0 →KSbckup L0=540 fb-1

Belle, PRL 99, 131803 (2007), 540fb-1 Systematics breakdownmodel error

better underst. of DCS/CF;arbitrary ½ of uncertainty takenas scaling;rest non-scaling


D0 →KSbckup L0=540 fb-1

Belle, PRL 99, 131803 (2007), 540fb-1 Systematics breakdownexp. error

all major sourcesscaling


Systematics bckup


1. Phenomenology

x and y

D0 D0

K+

K-

I.I. Bigi, N. Uraltsev, Nucl. Phys. B592, 92 (2001);A.F. Falk et al., PRD69, 114021 (2004)

W+

W-

D0 D0

The duration of passion is proportionate with the original resistance of the woman.

H. de Balzac (1799 -1850)

unique for D0’s: down q’s loop; mixing: 30 years after discovery

222** )( dsudcdcsus mmVVVV DCS SU(3) breaking

d,s,b

d,s,b

)10(|||,| 2Oyx)10(|~| 5Oxdifficult to estimate


D0: first two quark generations;CKM elements ≈ real;

using CKM unitarity:

bellow current exp. sensitivity; signals New Physics

1. Phenomenology

CP violationVcs

Vus*

D0

K-

K+

)(VV

VV

Df

Df-

uscs

ubcb 3*

*

0

0

10~arg O

)(

0

0

0

0

0

0

2/1

)2/1(

),2

1(,2

1

,

fi

D

DM

MD

D

eA

RA

Df

Df

p

q

A

p

qA

Df

Df

RDf

Df

parameterization: RD ≠1: Cabbibo suppression

AD ≠0: CPV in decay AM ≠0: CPV in mixing ≠0 : CPV in interference


2. MeasurementsE)(3770) →D0D0

at threshold D0D0 in C=-1 state effective Br’s depending on mixing param.: y, RM=(x2+y2)/2, RDcos

S±: CP eigenstates

e-: Xefit to set of single and double Br’s

Br(D0D0 →fi/fj)Br(D0 →fi)Br(D0 →fj)

Br(D0D0 →fiX)Br(D0 →fi)

single D0 reconstr.

both D0 reconstr.

)1()1(

)(

)(),(

2

2

221

yBrBry

eDBr

eDBreDSDBr

eSS

S

measured from ST rates

uncorrelatedproduction

uncorrelatedproduction

Cleo-c, PRD78, 012001 (2008), 281pb-1

(RWS=(K+-)/(K-+))


3. Prospects and summaryA) Mixing parameters

Cleo-c results improved signif. with higher stat.;(all estimates based on )

x, y related measurements of similar or better accuracy at Super-B with modest lumin.;

already constrained with reasonable accuracy from combination of x’2, y’, x, y meas.;

(yCP) [%] B

(y) [%] B

(x) [%] B

(RM) [10-3] charm(x’2) [10-3] B

0.5 5.0

L [fb-1]

L [ab-1]

(y) [%] charm

0.5 5.0

L [fb-1]

L [ab-1]

L [fb-1]

(√RDcos) [10-2] charm

Prediction is very difficult, especially of the future.

N. Bohr (1885 - 1962)

Cleo-c, PRD78, 012001 (2008), 281pb-1


3. Prospects and summaryA) Mixing parameters

asymmetric factory at (3770):

for same <z> as at (4S) ~2 (0.42 at Belle), E(e-/e+)=8 GeV/0.45 GeV (8 GeV/3.5 GeV at Belle);

resolution:resD ~ res

B (B/D) ~0.3 ps ~D0

N(S+K-+, S+e-)~1300 @ 281 pb-1

y~0.1% with 2 ab-1 (stat. only)

NN

tt

tyt

etytytd

fSDDd

res

ty

t

8~

||||

8||;1||

sinhcosh)(

222

22

2

||00


3. Prospects and summaryB) CPV parameters

various options at (3770); decays to same sign CP eigenstates: (assuming no direct CPV)

suppressed by RM; not feasible;

L [ab-1]

(A) [%] B(|q/p|) B() [rad] B

160

60

00

0

2

2

102.1~104

/;/

1)(2)(2

)(sin

sin)(2)(

)(

fb

NN

SBrRNSBrR

N

NSBrR

XS

SSr

NN

M

N

M

r

M

LLLLLL

>>



various options at (3770); untagged asymmetry:

ACP linear in CPV and mixing param., feasible (stat. only); systematics from charge dependent asymm.? also possible at B-factories

022

200

0

0000

0000

sin4

)(

/2

)(

1sin2

)(sin

sinsin2cos2

sinsin2

)()()()(

)()()()(

LL

LL

yR

N

N

yR

yRxA

yRA

KDKDKDKD

KDKDKDKDA

D

ACP

ACP

K

KACP

D

ACP

DM

DCP

CP

>>

0.2 0.5 0.9 sin

L[fb-1]

1400

1000

600

200

300 fb-1

current

RD, y uncertainty



D0D0 in C=+1 state (D0D0 );tagged asymmetry:

MMCCP

MCCP

ARAbn

AxA

yeSeS

eSeSA

1

1

:..

sincos2)()(

)()(



various options at (3770); CPV in mixing:

ACP linear in CPV param., feasible (stat. only); systematics from e- spectrum extrapolation (cancels in ACP)? (AM)~1% with 300 fb-1

sensitivity better than at Super-B;

)(4

))(()(5.0)(

2)()(

)()(0000

0000

eeN

eeNAA

AAeeDDeeDD

eeDDeeDDA

CPM

MCP

CP

(A) [%] B(|q/p|) B() [rad] B

L [ab-1]



various options at (3770); direct CPV:

ACP linear in CPV param., feasible (stat. only); systematics from e- spectrum extrapolation (cancels in ACP)? sensitivity better than at Super-B;

a complete overview of physics cases (for BES-III)can be found in

)(

))(()(2)(

2

)()(

)()(0000

0000

eKKN

eKKNAA

AA

eSDDeSDD

eSDDeSDDA

CPD

DCP

CP

(AD) [%] charm(AD) [%] B

0.5 5.0

L [fb-1]

L [ab-1]

K.T. Chao, Y. Wang, editors, arXiv:0809.1869


Systematics bckup (3770) →D0D0

22

0

2

cos006.0

/

036.0

LLR

22

0

2 %2.1/

%1.6

LLy

L0=281 pb-1

assume sensitivity ony is mainly due to S±e-

RDcos is mainly due to S±K-+

RM is mainly due to K-+K-+

calculate fraction of non-scaling syst. on DT yields in total relative error:S±e- (y) (non-scaling)/(total)=15% extrap. of e- momentumS±K-+ (RDcos) (non-scaling)/(total)=15% FSR, sideband subtr.K-+K-+ (RM) (non-scaling)/(total)=2.4% FSR

23

2

0

32 1004.0

/

107.1

LLRM

Cleo-c, PRD78, 012001 (2008), 281pb-1


bckup (3770) →D0D0

constraints average direct meas. (fit w/o external input)

0 1 2 3 4 5 [rad]

y’=

yco

s-x

sin

[%]

1.0

0.5

0

-0.5

-1.0

y’ measured

m

easu

red

0 1 2 3 4 5 [rad]

cos

1

0

-1


Phenomenology bckup

n nD

Cw

Cw

D

Cw

D iEM

DHnnHD

MDHD

MiM

0110

02012 2

1

2

1)

2(

055

02

222**

2

2020 |)1()1(|

)(

4DcucuD

m

mmVVVV

GDHD

c

dsusudcdcs

FCw

short distance:

DCS SU(3) breakingG. Burdman, I. Shipsey, Ann.Rev.Nucl.Sci. 53, 431 (2003) |x| ~ O(10-5)

long distance:

absorptive part (real interm. states) ydispersive part (off-shell interm. states) x

D0 D0

K+

K-

I.I. Bigi, N. Uraltsev, Nucl. Phys. B592, 92 (2001);A.F. Falk et al., PRD69, 114021 (2004)

|x|, |y| ~ O(10-2)

D0 mixing: rare process in SM;possible contrib. from NP

x and y in SM 2nd order perturb.:

c

u

u

c

d, s, b d, s, b

W+

W-

D0 D0

Vci*

Vcj

Vuj*

Vui


K+-0 bckup BaBar, arXiv:0807.4567, 384fb-1

D0 →K+ -0

KK

KKxyyyxxsincos''sincos''

BaBar, Lepton Photon 07, 384fb-1

no mixing point 0.8% C.L.

K: unknown strong phase shift DCS/CF

t

mix

f

interf.

ffff

DCS

f

etyx

A

txyAA

AtDK

]

||[

222

2

2200

4

''''||

)sin''cos''(||||

)(

separate WS/RS Dalitz distributions; t-distrib. analogous to D0 →K+ -;

RS t-integratedDalitz analysis;WS Dalitz analysis;


K+K- / +- bckup Belle, PRL 98, 211803 (2007), 540fb-1

Fitsimultaneous binned likelihood fit to K+K- /K-+/+- decay-t, common free yCP

)(')'(/' tBdttteN

dt

dN t R

R : ideally each i Gaussian resol. term with fraction fi; : described by 3 Gaussians

N

i kikki tsttGwftt

1

3

10 ),,'()'( R

= 408.7±0.6 fs

event-by-event t

K-+

parameters of R depend slightlyon data taking conditions

trec-tgen/t


K+K- / +- bckup

equal t0 assumption

yCP=t0CP - t0

K / K

from MC cocktail, includingrunning periodswith slight misalign.of SVD

Belle, PRL 98, 211803 (2007), 540fb-1


(3770) →D0D0 bckup

2

211200

2100

00,,

200

)(

2

1,

;,,)(

;)(

DjDiDjDiijDD

DDDD

DjiDjiAA

AAAAijDD

jiji

jiji

D0, D0 in anti-symmetric state


Triple product correl. bckupD →K*(p1,1)K*(p2,2)

T(pi,i) = -pi,i;

but AT ~ sin(): weak phase: strong phase;

)0)(()0)((

)0)(()0)((

211211

211211

pNpN

pNpNAT

:2

T

TTCPT

A

AAA

asymmetry of conjugated process

ATCP ~ sincos

n.b.: ACPdir ~ sinsin


T-odd moments bckupD →KK

: angle between KK and planes;

:

:sincossincos

sincossincos

sincossincos

33

2,12,1

,

32

22

1

32

22

1

TCPd

dd

d

direct CPV;

CPV;

d 0 mixing @ superbelle

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