1 E831-FOCUS Stato dell’analisi e prospettive Sandra Malvezzi INFN-Milano.
-
Upload
devonte-cobbs -
Category
Documents
-
view
217 -
download
0
Transcript of 1 E831-FOCUS Stato dell’analisi e prospettive Sandra Malvezzi INFN-Milano.
1
E831-FOCUSStato dell’analisi e prospettive
Sandra Malvezzi INFN-Milano
2
Over 1 million reconstructed!!
Successor to E687. Designed to study charm particles produced by ~200 GeV photons using a fixed target spectrometer with upgraded Vertexing, Cerenkov, E+M Calorimetry, and Muon id capabilities. Includes groups from USA, Italy, Brazil, Mexico, Korea
1 million charm particles reconstructed into DK , K2 , K3
FOCUS Spectrometer
3
LaLa collaborazione collaborazione FOCUSFOCUS
Univ. of California-Davis, CBPF-Rio de Janeiro, CINVESTAV Mexico City, Univ. Colorado-Boulder,
FERMILAB, Laboratori Nazionali di Frascati, Univ. of Illinois-Urbana-Champaign,
Indiana Univ.-Bloomington, Korea Univ.-Seoul, INFN and Univ.-Milano,
Univ. of North Carolina-Asheville, INFN and Univ.-Pavia, Univ. of Puerto Rico Mayaguez,
Univ. of South Carolina-Columbia, Univ. of Tennessee-Knoxville,
Vanderbilt Univ.-Nashville, Univ. of Wisconsin-Madison, Yonsei Univ.-Seoul
4
Cronologia E831-FOCUS
•1996-1997 Presa dati•1998 Completata la ricostruzione di
piu`di 6 Miliardi di eventi•1999 ora
Sub-skimOttimizzazione MCAnalisiPresentazioni a conferenzePubblicazioni risultati di fisica
5
Attività 2003
Analisi: - Presentazioni a conferenze - Articoli su riviste
Frascati – Spettroscopia degli stati eccitati (L=1) del mesone D
Milano – Studio dei mesoni con charm
Pavia – Studio dei barioni con charm
6
Stato dell’analisi e prospettive•Nel periodo Giugno 2002-Giugno 2003 sono stati pubblicati 20 articoli su riviste internazionali (di cui 13su Physics Letters B)
•Entro la fine del 2004 sono previste altre 20 pubblicazioni
•Fondamentale contributo alla fisica del charm •Lifetimes
•Semileptonic decays
•Hadronic decays
•Rare decays
7
An important lesson from
for the B physics and CP studies
“The advantages of high-statistics for the interpretation of Heavy-Flavour hadronic-decay dynamics
will vanish without a strategy for controlling strong effects among particles involved
in weak-decay processes ”
8
Complication for Dalitz plot analysis
had to face the problem of dealing with light scalar particles populating charm meson
hadronic decays, such as D, D
Require understanding of light-quark hadronic physics including the riddle of and
(i.e, and states produced close to threshold), whose existence and nature is still controversial
9
A bridge of language, knowledge and measurements between the two worlds
of Light Mesons and Heavy Flavoursis necessary
• S-matrix and its representations• Two-body unitarity • Analyticity • Limits of the Breit-Wigner approximation etc..
10
Analysis techniques CAN and MUST be improved now in view of extensive application in high-statistics experiments (Cleo-c, Babar, Belle, BTeV, LHC-b etc...) for precision studies of CP and reliable New Physics measurements
Pioneering work performed by
11
An instructive example from FOCUS
Milano group
D
analogy with operatively:
complete Dalitz plot analysis (time-dependent) to deal withall interference with other () intermediate channels
B
crucial for determination of the angle of the SM unitarity triangle
12
For a well-defined wave with specific isospin and spin (IJ)characterized by narrow and well-isolated resonances, we knowhow.• the propagator is of the simple Breit-Wigner type and the amplitude is
How can we formulate the problem?
D r |
1 2
3
The problem is to write the propagator for the resonance r
rr
3
1
2
1 3 13 2 212
1(cos )
J Jr
D r Jr r r
A F F p p Pm m im
����������������������������traditionalisobar model
13
when the specific IJ–wave is characterized by broad and heavily overlapping resonances (just like scalars!), the problem is not so simple.
1( )I iK where K is the matrix for the scattering of particles 1 and 2.
In this case it can be demonstrated on very general grounds that, in the context of the K-matrix approach, the propagator may be written as
Indeed, it is very easy to realize that propagation is no longer dominated by a single resonance, but is the result of complicated interplay among resonances.
i.e., to write down the propagator we need the scattering matrix
In contrast
14
•Based on “first principles” of S-matrix scattering theory
The K-matrix formalism E.P.Wigner,Phys. Rev. 70 (1946) 15
S.U. Chung et al.Ann. Physik 4 (1995) 404
1 1K T i 1( )T I iK K
1/ 2 1/ 22S I i T S scattering matrix
= phase space
15
•From T
to F
1( )T I iK K
From scattering to production: the P-vector approach
I.J.R. AitchisonNucl. Phys. A189 (1972) 514
1( )F I iK P
known from scattering data
describes coupling of resonances to D
16
K-matrix advantages
• An elegant and direct way of incorporating the
two-body unitarity constraint • Proper handling of overlapping and wide resonances• Straightforward inclusion of already known physics
and disadvantages
requires translation into T-matrix to get the “physics”
17
* p0n,n, ’n, |t|0.2 (GeV/c2)GAMSGAMS
* pn, 0.30|t|1.0 (GeV/c2)GAMSGAMS
* BNLBNL
*p- KKn
CERN-MunichCERN-Munich
::
* Crystal BarrelCrystal Barrel
* Crystal BarrelCrystal Barrel
* Crystal BarrelCrystal Barrel
* Crystal BarrelCrystal Barrel
pp
pp , ,
pp K+K-, KsKs, K+s
np -, KsK-, KsKs-
-p0n, 0|t|1.5 (GeV/c2)E852E852*
At rest, from liquid 2H
At rest, from gaseous
At rest, from liquid
At rest, from liquid
2H
2D2H
“K-matrix analysis of the 00++-wave in the mass region below 1900 MeV’’ V.V Anisovich and A.V.Sarantsev Eur.Phys.J.A16 (2003) 229
A description of the scattering ...
A global fit to all the available data has been performed!
18
FOCUS D s +
++- analysis
Observe:
•f0(980)
•f2(1270)
•f0(1500) Sideband
Signal
Yield Ds+ = 1475 50
S/N Ds+ = 3.41
19
First fits to charm Dalitz plots in the K-matrix approach!
C.L fit 3 %
sD
Low mass projection High mass projection
+
+20 +
(S - wave)π 87.04 ± 5.60 ± 4.17 0(fixed)
f (1275)π 9.74 4.49 2.63 168.0 18.7 2.5
ρ (1450)π 6.56 ± 3.43 ± 3.31 234.9 ±19.5 ±13.3
decay channel phase (deg)fit fractions (%)
20
sD
•No significant direct three-body-decay component
•No significant (770) contribution
sD
Marginal role of annihilation in charm hadronic decays
But need more data!
21
Yield DYield D++ = 1527 = 1527 5151
S/N DS/N D++ = 3.64 = 3.64
FOCUS D+ ++- analysis
Sideband Signal
22
2lowm
2highm
D
C.L fit 6.8 %
K-matrix fit results
Low mass projection High mass projection
+
+2
0 +
(S - wave)π 56.46 ± 3.78 ±1.02 0(fixed)
f (1275)π 12.26 1.73 0.21 -38.6 20.9 4.2
ρ (770)π 26.89 ± 3.78 ±1.08 -128.9 ±18.5 ± 3.7
decay channel phase (deg)fit fractions (%)
No new ingredient (resonance) required not present in the scattering!
23
With
Without
C.L. ~ 7.5%
Isobar analysis of D+ ++would instead require a new scalar meson:
C.L. ~ 10-6
m = 442.6± 27.0 MeV/c = 340.4 ± 65.5 MeV/c
24
A.D. Polosa: “ Hadronic pollution in B”?
J.A. Oller: “On the resonant and non-resonant contributions to B”
CKM03 in B
25
Conclusions•The K-matrix approach has been applied to charm decays for the first time
Such a result was not at all obvious! Such a result was not at all obvious!
•Full application to forthcoming high-statistics charm and beauty experiments for precision studies and search of New Physics !
•The same K-matrix description gives a coherent picture of
•Two-body scattering measurements•Light-quark spectroscopy experiments•Charm-decay data
26
Slides for questions
• Slides for questions
27
m = 1473.0 8.8 MeV/c= 109.5 16.3 MeV/c
20 0 1
2 2 2 20 12 0 0 1 1 2 2( )
m
m m im
K-matrix coupled-channel parametrization
FOCUS fit results
0 (980)f
0 (1475)S single channel Breit-Wigner
FOCUS fit results
0 0,m K-matrix mass and width
1 2γ , γ dimensionless normalizedcoupling constants
to and KK channels1 2ρ ,ρ
and KK phase space
Preliminary
22
0m = 963.6 ± 5.4
0Γ = 284.2 ± 93.22
2
21
γ= 2.04 ± 0.56
γ
MeV/c
MeV/c
22
PDG does not help us!Large uncertainties in scalar-resonance paramenters
28
f2(1270)f0(980)
f0(980)
f2(1270)S0(1475)
r
j
2iδ 2 2r r 12 13
r 2iδ 2 2j j 12 13j
a e A dm dmf =
a e A dm dm
Isobar approach results
Preliminary
+2
+0
+00
NR 24.85 ± 3.99 ± 5.67 246.8 ± 4.7 ± 4.8 0.516 ± 0.040 ± 0.055
f (1275)π 9.58 ±1.22 ±1.20 141.7 ± 6.8 ± 6.6 0.321 ± 0.021 ± 0.021
f (980)π 93.23 ± 2.39 ± 2.55 0(fixed) 1(fixed)
S (1475)π 17.18 ± 2.94 ± 3.00 248.9 ± 3.5 ± 5.7 0.429 ± 0.039 ± 0.041
ρ (1 +450)π 4.56 ± 0.79 ± 0.89 191.0 ±13.8 ±17.6 0.221 ± 0.020 ± 0.023
decay channel amplitude coefficientphase (deg)fit fractions (%)
C.L. Fit 7.2%
29
f0(1500) PDG m = 1507 5 MeV = 109 7 MeV Preliminar
y
if
then0Γ (980) = 394.5 ±107.1
0 (980) (104.20 3.30)%
(43.53 4.88)%
f
NR
fit fractions:
C.L. 2%
Instability depending on the 1500 MeV region parametrization!
30
2( )
( )ai aj
ij ija a
g gK c s
m s
Resonances in K-matrix formalism
where
2 ( )ai a aig m m
1( )T I iK K
S.U. Chung et al.Ann.Physik 4(1995) 404
E.P.Wigner,Phys.Rev.70 (1946) 15
31
... from scattering to production:the P-vector approach
2( )i
i
gP
m s
(complex) carries the
production information i i iP P d
1( )F I iK P
I.J.R. AitchisonNucl.Phys. A189 (1972) 514
known from scattering data
32
( ) ( ) 200 0
20 0 0
1 2( )
( )(1 )
scatti j scatt A
ij ij scattA A
g g s s s mK s f
m s s s s s s
( )ig
is the coupling constant of the bare state to the meson channelscatt
ijf0s describe a smooth part of the K-matrix elements
20 0( 2) ( )(1 )A A As s m s s s suppresses the false kinematical singularity
at s = 0 near the threshold
and
is a 5x5 matrix (i,j=1,2,3,4,5)
'
IJijK
K K1= 2= 3=4 4= 5=
A&S
33
A&S K-matrix poles, couplings etc.
4 '
0.65100 0.24844 0.52523 0 0.38878 0.36397
1.20720 0.91779 0.55427 0 0.38705 0.29448
1.56122 0.37024 0.23591 0.62605 0.18409 0.18923
1.21257 0.34501 0.39642 0.97644 0.19746 0.00357
1.81746 0.15770 0.179
KKPoles g g g g g
0 11 12 13 14 15
0
15 0.90100 0.00931 0.20689
3.30564 0.26681 0.16583 0.19840 0.32808 0.31193
1.0 0.2
scatt scatt scatt scatt scatt scatt
A A
s f f f f f
s s
34
A&S T-matrix poles and couplings
4 '13.1 96.5 80.9 98.6 102.1
116.8 100.2 61.9 140
( , / 2)
(1.019, 0.038) 0.415 0.580 0.1482 0.484 0.401
(1.306, 0.167) 0.406 0.105 0.8912 0.142
KKi i i i i
i i i i
m g g g g g
e e e e e
e e e e
.0 133.0
97.8 97.4 91.1 115.5 152.4
151.5 149.6 123.3 170.6
0.225
(1.470, 0.960) 0.758 0.844 1.681 0.431 0.175
(1.489, 0.058) 0.246 0.134 0.4867 0.100 0
i
i i i i i
i i i i
e
e e e e e
e e e e
133.9
.6 126.7 101.1
.115
(1.749, 0.165) 0.536 0.072 0.160 0.313
i
i i i i i
e
e e e e e
A&S fit does not need a as measured in the isobar fit