2,792 research outputs found
Resolving the () ambiguity in
I propose an alternative method for measuring the violating phase
() without ambiguity in an extended SU(2) isospin triangle
analysis, which can ultimately be achieved by exploiting interference effects
between and in a
time-dependent flavour-tagged amplitude analysis. Under certain assumptions on
the effective in each channel, I demonstrate with an idealised
amplitude model that potential deviations in the measured due to
penguin contamination in are sufficiently large
within current experimental uncertainties that this programme could be executed
with Run 3 data at LHCb and easily at Belle II.Comment: 19 pages, 7 figures, replaced with journal versio
Impact of systematic and amplitude model correlations within and between systems of combined input: A case study with ()
The pursuit of experimental precision in the -violating weak phase
() is not without its challenges, in part due to the need to
combine multiple physical observables from various related decay channels, and
therein lies a fundamental issue. Similarities in analysis procedures give rise
to systematic correlations between the measured inputs constraining
that must be taken into account to avoid bias. Specifically, in the case of the
irreducible model uncertainty accompanying analyses involving the meson,
it is demonstrated that ignoring correlations derived from its pole parameters,
or indeed even treating correlations individually contained within each decay
channel, can ultimately lead to a bias in of .
Correct treatment on the other hand, markedly reduces wandering of its central
value as a function of the model uncertainty strength with the added dividend
of a further improved overall uncertainty. Bias in the combination of and is also seen to depend on the statistical
strength of the former in relation to that of the model uncertainty in the
latter. This work can inspire other studies into the points at which systematic
correlations beyond those determined in single measurements matter in
combinations leading to other -violating weak phases such as
(), () and .Comment: 25 pages, 8 figures, 11 tables, replaced with journal version. This
article should be considered in conjunction with arXiv:2110.0818
Rescaling the isospin triangle argument for constraining (): consolidating Belle II and a potential path forward for LHCb
A rescaling of the SU(2) isospin triangles constraining ()
that relies on measurements of the experimentally cleaner relative branching
fractions, as opposed to those absolute, is proposed. Paving the way towards
more systematically sustainable analysis, this method promises to eliminate a
dominant systematic at Belle II amongst others, namely the uncertainty on the
number of pairs in data. Furthermore, a constraint in the
system at LHCb that is more independent of Belle II input is
shown to become viable even without a measurement of violation in .Comment: 10 pages, 7 figures, replaced with journal version. This article
should be considered in conjunction with arXiv:2108.0618
Evidence for CP Violation in B0 -> D+D- Decays
We report measurements of the branching fraction and CP violation parameters
in B0 -> D+D- decays. The results are based on a data sample that contains 535
x 10^6 BBbar pairs collected at the Upsilon(4S) resonance, with the Belle
detector at the KEKB asymmetric-energy e+e- collider. We obtain [1.97 +- 0.20
(stat) +- 0.20 (syst)] x 10^(-4) for the branching fraction of B0 -> D+D-. The
measured values of the CP violation parameters are: S = -1.13 +- 0.37 +- 0.09,
A = 0.91 +- 0.23 +- 0.06, where the first error is statistical and the second
is systematic. We find evidence of CP violation in B0 -> D+D- at the 4.1 sigma
confidence level. While the value of S is consistent with expectations from
other measurements, the value of the parameter A favors large direct CP
violation at the 3.2 sigma confidence level, in contradiction to Standard Model
expectations.Comment: 12 pages, 3 figures, submitted to PR
Study of the Baryon-Antibaryon Low-Mass Enhancements in Charmless Three-body Baryonic B Decays
The angular distributions of the baryon-antibaryon low-mass enhancements seen
in the charmless three-body baryonic B decays B+ -> p pbar K+, B0 -> p pbar Ks,
and B0 -> p Lambdabar pi- are reported. A quark fragmentation interpretation is
supported, while the gluonic resonance picture is disfavored. Searches for the
Theta+ and Theta++ pentaquarks in the relevant decay modes and possible
glueball states G with 2.2 GeV/c2 < M-ppbar < 2.4 GeV/c2 in the ppbar systems
give null results. We set upper limits on the products of branching fractions,
B(B0 -> Theta+ p)\times B(Theta+ -> p Ks) Theta++
pbar) \times B(Theta++ -> p K+) G K+) \times
B(G -> p pbar) < 4.1 \times 10^{-7} at the 90% confidence level. The analysis
is based on a 140 fb^{-1} data sample recorded on the Upsilon(4S) resonance
with the Belle detector at the KEKB asymmetric-energy e+e- collider.Comment: 14 pages, 13 figure files, update of hep-ex/0409010 for journal
submisssio
Measurements of Charmless Hadronic b->s Penguin Decays in the pi+pi-K+pi- Final State and First Observation of B0 -> rho0K+pi-
We report measurements of charmless hadronic B^0 decays into the pi+pi-K+pi+
final state. The analysis uses a sample of 657x10^6 BBbar pairs collected with
the Belle detector at the KEKB asymmetric-energy e+e- collider at the Y(4S)
resonance. The decay B^0 -> rho0 Kpi is observed for the first time; the
significance is 5.0sigma and the corresponding partial branching fraction for
M_Kpi in (0.75,1.20) GeV/c^2 is [2.8 +- 0.5(stat) +-0.5(syst)] x 10^{-6}. We
also obtain the first evidence for B^0 -> f0Kpi with 3.5sigma significance and
for B^0 -> pi+pi-K*0 with 4.5sigma significance. For the two-body decays B^0 ->
rho0K*0 and B^0 -> f0K*0, the significances are 2.7sigma and 2.5sigma,
respectively, and the upper limits on the branching fractions are 3.4x10^{-6}
and 2.2x10^{-6} at 90% confidence level.Comment: 6 pages, 3 figures. accepted by PRD(RC
Search for the h_c meson in B^+- ->h_c K^+-
We report a search for the meson via the decay chain , \etac \gamma with and
. No significant signals are observed. We obtain upper limits on the
branching fractions for in bins of the
invariant mass. The results are based on an analysis of 253
fb of data collected by the Belle detector at the KEKB
collider.Comment: 12 pages, 6 figures, submitted to Phys. Rev.
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