The status of D and D* decays in DECAY.DEC

D* decays : These decays are well measured, and branching fractions are well known. For example, for D*+: Branching Fraction Decay mode Decay model 0.6830 D0 pi+ VSS 0.3060 D+ pi0 VSS 0.0110 D+ gamma VSP_PWAVE The branching fractions in this table are from 1996 Particle Data Book, and the VSS decay model simply describes "vector to two (pseudo)scalars" decays, and produces the correct angular distributions. For Ds*+, the branching fractions are roughly consistent with those measured by CLEO (see, e.g., CLNS 95/1346). D+/D- decays : Semileptonic and leptonic decays All major semileptonic modes (see the table below for D+) are implemented in DECAY.DEC with the ISGW2 decay model. The branching fractions are all measured (the values listed in the table below are roughly consistent with those listed in PDB), and the improved ISGW model (ISGW2) is known to describe exclusive semileptonic modes quite well. The leptonic decays, which have not yet been observed directly, are assigned branching fractions obtained from simple scaling. Branching Fraction Decay mode Decay model 0.0504 anti-K*0 e+ nu_e ISGW2 0.0929 anti-K0 e+ nu_e ISGW2 0.0504 anti-K*0 mu+ nu_mu ISGW2 0.0929 anti-K0 mu+ nu_mu ISGW2 0.0009 mu+ nu_mu PHSP 0.0024 tau+ nu_tau PHSP Note that: 1). Some semileptonic modes that are listed in DECAY.DEC have not yet been observed. For example, D+ -> eta e+ nu_e, which is currently assigned the branching fraction of 0.0028, has not been measured, and the branching fraction is really a guess based on some simple scaling arguments. 2). Of special importance for tagging: the inclusive semileptonic rate for DECAY.DEC is roughly 16.5%, which is quite consistent with the PDG value of (17.2 +- 1.9)%. Two body decays Two-body decays constitute about 30% of the total rate, which is approximately consistent with what DECAY.DEC gives (about 32%). The major two-body modes appearing in DECAY.DEC (e.g., anti-K0 pi+) are both well-measured and well-modelled. A few significant two-body modes that are not listed exclusively are included as resonances in higher multiplicity modes (e.g., anti-K0 rho+ in anti-K0 pi+ pi0). Three-body K pi pi decays The modes with the largest branching fractions (see the table below for D+) have been fully implemented with the measured resonant structure. The model used is D_DALITZ. Branching Fraction Decay mode Decay model Experiment 0.091 K- pi+ pi+ D_DALITZ E691 0.097 anti-K0 pi+ pi0 D_DALITZ MARK III (limited statistics for resonances!) More specifically, for the D+ -> K+ pi- pi- mode the measured resonances are K*bar(892)0 pi+, K*bar(1430)0 pi+, and K*bar(1680)0 pi+, and for the D+ -> anti-K0 pi+ pi0 mode the resonances are K0_bar rho and K*bar(892)0 pi+. Other K pi pi modes are assigned mostly measured branching fractions (from the PDG) and decay according to phase space. Other hadronic modes For most of these decays only phase space is used, and the branching fractions are taken from the PDG. Inclusive K yields (important for tagging) The overall K- yield for D+ modes in DECAY.DEC is approximately 25%, which is roughly the PDG value (24.2 +- 2.8)%. The overall K+ yield is about 4.5%, which is comparable with the PDG value of (5.8 +- 1.4)%. The overall K0-K0_bar yield is approximately 60%, which can be compared with the PDG value of (59 +- 7)%. D0/D0_bar decays : Semileptonic and leptonic decays Similarly to D+, all major semileptonic modes (see the table below for D0) are implemented in DECAY.DEC with the ISGW2 decay model. Branching Fraction Decay mode Decay model 0.0198 K*- e+ nu_e ISGW2 0.0364 K- e+ nu_e ISGW2 0.0198 K*- mu+ nu_mu ISGW2 0.0364 K- mu+ nu_mu ISGW2 The inclusive semileptonic rate is approximately 6.8%, which is compatable with what the PDG gives: (7.7 +- 1.2)%. Two body decays Two-body decays constitute about 50% of the total rate, which is approximately consistent with what DECAY.DEC gives(about 49%). Just as in the case of D+, the major two-body modes appearing in DECAY.DEC are well-measured and well-modelled, and significant two-body modes that are not listed exclusively are included as resonances in higher multiplicity decays. Three-body K pi pi decays The modes with the largest branching fractions (see the table below for D0) have been fully implemented with the measured resonant structure. The model used is D_DALITZ. Branching Fraction Decay mode Decay model Experiment 0.1307 K- pi+ pi0 D_DALITZ E691 0.0540 anti-K0 pi+ pi- D_DALITZ E691 More specifically, for the D0 -> K- pi+ pi0 mode the measured resonances are K*bar(892)0 pi0, K*(892)- pi+, and K- rho(770)+, and for the D0 -> anti-K0 pi+ pi- mode the resonances are K*(892)- pi+ and K0_bar rho(770)0. Other K pi pi modes are assigned mostly measured branching fractions and decay according to phase space. Other hadronic modes For most of these decays only phase space is used, and the branching fractions are taken from the PDG. Inclusive K yields The overall K- yield for D0 modes in DECAY.DEC is approximately 57%, which is consistent within errors with the PDG value: (53 +- 4)%. The overall K+ yield is about 3.41%, which is close to the PDG value of (3.4 +- 0.5)%. The overall K0-K0_bar yield is approximately 36%, which can be compared with the PDG value of (42 +- 5)%. Ds+/Ds- decays : Semileptonic and leptonic decays All major semileptonic modes (see the table below for Ds+) are implemented in DECAY.DEC with the ISGW2 decay model. Branching Fraction Decay mode Decay model 0.0200 phi e+ nu_e ISGW2 0.0388 eta e+ nu_e ISGW2 0.0168 eta' e+ nu_e ISGW2 0.0200 phi mu+ nu_mu ISGW2 0.0388 eta mu+ nu_mu ISGW2 0.0168 eta' mu+ nu_mu ISGW2 Hadronic modes For most of these decays only phase space is used. Inclusive K yields The overall non-K K_bar yield for Ds+ modes in DECAY.DEC is approximately 75%, which is consistent within errors with the PDG value: (64 +- 17)%.

natalia@charm.physics.ucsb.edu