for each topic:
summary of the present experimental situation
a comment about the next future reach
to be done
a more precise picture of the experimental status within 5 and 10 years
BaBar, Belle, Cleo-c, CDF, BEPC, LHC-b, BTeV
Charm lifetimes
Motivation: investigation of non-spectator processes FOCUS (*) produced new lifetimes results with precision better
than the previous world average (○), PDG 2002.
Already at the level of comparison with theory.
Systematics will dominate
Rare decays
FOCUS improved results by a factor of 1.7 –14: approaching theoretical predictions for some of the modes but still far for the majority CDF and D0 can trigger on dimuons promising Motivation: lepton number violation study
investigation of long range effects and SM extention CDF Br(D0m+m-)<2.4 x10-6 @ 90% C.L.
is the best limit for this mode (65 pb-1 data)
Mixing
Motivation: suppressed in the charm sector in the SM. If “measured”, would suggest SM extention Future is @ Babar & Belle
Summary of reach
Where we are and where we go
The semileptonic sector
FOCUS number is 1.59
standard deviation
below CLEO and 2.1
standard deviation
above E691 All values consistent with their average value with a CL of 19% Motivation: semileptonic decays are the easiest way
to determine CKM elements Branching ratio
...and form factors
The vector and axial form factors are generally parametrized
by a pole dominance form Nominal spectroscopic
pole masses D+ d d u
u s
form factors FOCUS analysis is the first to include the effects on the acceptance due to changes
in the angular distribution brought about the s-wave interference Form Factor lattice calculations available!
0.490.100.12 CLEO 0.570.150.15 ARGUS 0.580.170.07 E687 0.540.050.04 CLEO2 0.540.0330.048 FOCUS muon electron Group Br(Ds fmn/ Ds fp)
form factors
Most precise measurement to date
very consistent with D+K0*m+n
very consistent with th. expectation Cleo-c expects experimental error in
most of the measurements in the sl sector in the range
1 to a few %
Hadronic decay investigation
A few slides follow about Dalitz plot analysis
“Future” of hadronic decays
Full observation of the decay (for three-body channels)
Learn about strong effects (but also a complication
for the analysis!)
CP investigation (see example of D±K K±p±)
Interplay between charm (and beauty) decays and light meson spectroscopy (very clean samples!)
Motivation: Investigation of decay dynamics via Dalitz plot analysis The analysis is difficult, need an analysis strategy to keep
under control the strong effects accompanying the weak
decays of Heavy Flavours!
An instructive example from FOCUS Milano group analogy with operatively:
complete Dalitz plot analysis (time-dependent) to deal with
all interference with other (pp)p intermediate channels crucial for determination of the angle a
of the SM unitarity triangle
FOCUS D s + p +p +p - analysis Observe:
f0(980)
f2(1270)
f0(1500) Sideband Signal Yield Ds+ = 1475 50
S/N Ds+ = 3.41 f0(980) signal
is clean!
First fits to charm Dalitz plots in the K-matrix approach! C.L fit 3 % Low mass projection High mass projection decay channel phase (deg) fit fractions (%) Projections of the f0(980) signal
p+ p+ p- No significant direct three-body-decay component No significant r(770) p contribution p+ p+ p- r Marginal role of annihilation in charm hadronic decays A reliable measurements of the annihilation processes in
the hadronic sector is still missing.... need more data!
Yield D+ = 1527 51
S/N D+ = 3.64 FOCUS D+ p +p +p - analysis Sideband Signal
C.L fit 7.7 % K-matrix fit results Low mass projection High mass projection decay channel phase (deg) fit fractions (%) Good channel to investigate
the nature of the s meson
(aka the s puzzle) . No new ingredient (resonance)
required not present in the scattering!
With s Without s C.L. ~ 7.5% Isobar analysis of D+ p +p +p would instead require
a new scalar meson: s C.L. ~ 10-6 m = 442.6± 27.0 MeV/c
G = 340.4 ± 65.5 MeV/c preliminary
Comments