Quantum-correlated ψ(3770)→DD¯ decays collected by the CLEO-c experiment are used to perform first measurements of F+, the fractional CP-even content of the self-conjugate decays D→π+π−π0 and ...D→K+K−π0. Values of 0.968±0.017±0.006 and 0.731±0.058±0.021 are obtained for π+π−π0 and K+K−π0, respectively. It is demonstrated how modes of this sort can be cleanly included in measurements of the unitarity triangle angle γ using B∓→DK∓ decays. The high CP-even content of D→π+π−π0, in particular, makes this a promising mode for improving the precision on γ.
Quantum-correlated ψ(3770)→DD‾ decays collected by the CLEO-c experiment are used to perform a first measurement of F+4π, the fractional CP-even content of the self-conjugate decay D→π+π−π+π−, ...obtaining a value of 0.737±0.028. An important input to the measurement comes from the use of D→KS0π+π− and D→KL0π+π− decays to tag the signal mode. This same technique is applied to the channels D→π+π−π0 and D→K+K−π0, yielding F+πππ0=1.014±0.045±0.022 and F+KKπ0=0.734±0.106±0.054, where the first uncertainty is statistical and the second systematic. These measurements are consistent with those of an earlier analysis, based on CP-eigenstate tags, and can be combined to give values of F+πππ0=0.973±0.017 and F+KKπ0=0.732±0.055. The results will enable the three modes to be included in a model-independent manner in measurements of the unitarity triangle angle γ using B∓→DK∓ decays, and in time-dependent studies of CP violation and mixing in the D0D‾0 system.
The recent discovery, by the LHCb collaboration, of the Ξ$_{cc}^{+ +}$ doubly charmed baryon, has renewed interest in the spectroscopy of doubly heavy hadrons. Experimentally, however, searches for ...such states appear highly challenging. The reconstructed final states tend to involve multiple heavy flavoured (beauty or charm) hadrons, so the yield for any exclusive decay mode will be suppressed to unobservably low levels by the product of several branching fractions, each of which is typically 10$^{−3}$–10$^{−2}$. Noting that decays of double beauty hadrons are the only possible source of B$_{c}^{−}$ mesons that are displaced from the primary vertices of proton-proton collisions at the LHC, a more promising inclusive search strategy is proposed.
Abstract This article reports world averages of measurements of b-hadron, c-hadron, and $$\tau $$ τ -lepton properties obtained by the Heavy Flavor Averaging Group using results available through ...summer 2016. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, $$C\!P$$ C P violation parameters, parameters of semileptonic decays, and Cabbibo–Kobayashi–Maskawa matrix elements.
Weak decays of the vector Formula omitted and Formula omitted mesons to the Formula omitted final state provide novel potential to test the Standard Model of particle physics. Such processes have ...extremely small branching fractions as the vector mesons are able to decay through electromagnetic and (for the Formula omitted meson) strong interactions. Nonetheless, the production of copious quantities of these particles in LHC collisions, and the ability to exploit experimental techniques that can suppress background to low levels, provides good potential to reach interesting sensitivity. The possibility to reconstruct these processes as part of the decay chain of Formula omitted or Formula omitted mesons appears particularly attractive due to the clean experimental signature of the displaced vertex. Indeed, published LHCb data on Formula omitted decays already implies a stringent limit on the branching fraction of Formula omitted. Estimates are made on the achievable sensitivity to Formula omitted and Formula omitted decays with the LHCb experiment.
Abstract
Weak decays of the vector
$${{D} ^*} ^0$$
D
∗
0
and
$${{B} ^{*0}_{({s})}} $$
B
(
s
)
∗
0
mesons to the
$${\mu ^+\mu ^-} $$
μ
+
μ
-
final state provide novel potential to test the Standard ...Model of particle physics. Such processes have extremely small branching fractions as the vector mesons are able to decay through electromagnetic and (for the
$${{D} ^*} ^0$$
D
∗
0
meson) strong interactions. Nonetheless, the production of copious quantities of these particles in LHC collisions, and the ability to exploit experimental techniques that can suppress background to low levels, provides good potential to reach interesting sensitivity. The possibility to reconstruct these processes as part of the decay chain of
$${{{B} ^-}} $$
B
-
or
$${{B} _{c} ^+} $$
B
c
+
mesons appears particularly attractive due to the clean experimental signature of the displaced vertex. Indeed, published LHCb data on
$${{{B} ^-}} \rightarrow {{\pi } ^-} {\mu ^+\mu ^-} $$
B
-
→
π
-
μ
+
μ
-
decays already implies a stringent limit on the branching fraction of
$${{D} ^{*0}} \rightarrow {\mu ^+\mu ^-} $$
D
∗
0
→
μ
+
μ
-
. Estimates are made on the achievable sensitivity to
$${{D} ^{*0}} \rightarrow {\mu ^+\mu ^-} $$
D
∗
0
→
μ
+
μ
-
and
$${{B} ^{*0}_{({s})}} \rightarrow {\mu ^+\mu ^-} $$
B
(
s
)
∗
0
→
μ
+
μ
-
decays with the LHCb experiment.
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