121621545
Electromagnetic decay rates of neutral mesons
61210509
A HIGH SPEED DATA ACQUISITION SUBSYTEM FOR THE SSC
3 1: Introduction 3 2: Scopeof Our Work 6 3: Componentsof a DataAcquisition System 8 4: Milestones 21 5: Personnel 22 6: Budget 23 References 27
38939426
Observation of inclusive B decays to the charmed baryons Sigma c++ and Sigma c0.
Using data collected in the region of the [Upsilon](4[ital S]) resonance with the CLEO II detector operating at the Cornell Electron Storage Ring, we report on evidence for the production of [Sigma][sub [ital c]][sup ++] and [Sigma][sub [ital e]][sup 0] baryons in [ital B] decays, with [Sigma][sub [ital c]][r arrow][Lambda][sub [ital c]][sup +][pi]. This observation is based on 77[plus minus]19[Sigma][sub [ital c]][sup ++] and 76[plus minus]21[Sigma][sub [ital c]][sup 0] candidates from [ital B] decays. We find the product branching fractions [ital scrB]([ital [bar B]][r arrow][Sigma][sub [ital c]][ital X])[ital scrB]([Lambda][sub [ital c]][sup +][r arrow][ital pK][sup [minus]][pi][sup +]) for [Sigma][sub [ital c]]=[Sigma][sub [ital c]][sup ++], [Sigma][sub [ital c]][sup 0], and [Sigma][sub [ital c]][sup +] to be (2.1[plus minus]0.8[plus minus]0.7)[times]10[sup [minus]4], (2.3[plus minus]0.8[plus minus]0.7)[times]10[sup [minus]4], and less than 4.8[times]10[sup [minus]4] at 90% confidence level, respectively. A study of the [Sigma][sub [ital c]][sup ++] and [Sigma][sub [ital c]][sup 0] momentum spectra indicates that [ital B] decays to two-body final states with [Sigma][sub [ital c]] are suppressed.
121630940
Heavy quarks and tau
I present some recent experimental results on τ, charm, and bottom physics. CVC test and Michel parameters of the τ; mixing and fDs; and fB, Nc, η'K, ππ and Kπ, Vcb and Vub, lifetime and mixing, and CP violation searches in B decays.
117292627
Measurement of the charge asymmetry in the decay eta ---> pi+ pi- pi0
17397470
Inclusive decays of B mesons to charmonium.
We have used the CLEO-II detector at the Cornell Electron Storage Ringe (CESR) to study the inclusive production of charmonium mesons in a sample of 2.15 million {ital B{bar B}} events. We find inclusive branching fractions of (1.12{plus_minus}0.04{plus_minus}0.06)% for {ital B}{r_arrow}{ital J}/{psi}{ital X}, (0.34{plus_minus}0.04{plus_minus}0.03)% for {ital B}{r_arrow}{psi}{prime}{ital X}, and (0.40{plus_minus}0.06{plus_minus}0.04)% for {ital B}{r_arrow}{chi}{sub {ital c}1}{ital X}. We also find some evidence for the inclusive production of {chi}{sub {ital c}2}, and set an upper limit for the branching fraction of the inclusive decay {ital B}{r_arrow}{eta}{sub {ital c}}{ital X} of 0.9% at 90% confidence level. Momentum spectra for inclusive {ital J}/{psi}, {psi}{prime}, and {chi}{sub {ital c}1} production are presented. These measurements are compared to theoretical calculations.
45711213
Visible supersymmetry breaking and an invisible Higgs
A bstractIf there are multiple hidden sectors which independently break supersymmetry, then the spectrum will contain multiple goldstini. In this paper, we explore the possibility that the visible sector might also break supersymmetry, giving rise to an additional pseudo-goldstino. By the standard lore, visible sector supersymmetry breaking is phenomenologically excluded by the supertrace sum rule, but this sum rule is relaxed with multiple supersymmetry breaking. However, we find that visible sector supersymmetry breaking is still phenomenologically disfavored, not because of a sum rule, but because the visible sector pseudo-goldstino is generically overproduced in the early universe. A way to avoid this cosmological bound is to ensure that an R symmetry is preserved in the visible sector up to supergravity effects. A key expectation of this R-symmetric case is that the Higgs boson will dominantly decay invisibly at the LHC.
18358624
Dynamics of black hole formation in an exactly solvable model
We consider the process of black hole formation in particle collisions in the exactly solvable framework of 2+1 dimensional Anti de Sitter gravity. An effective Hamiltonian describing the near horizon dynamics of a head on collision is given. The Hamiltonian exhibits a universal structure, with a formation of a horizon at a critical distance. Based on it we evaluate the action for the process and discuss the semiclassical amplitude for black hole formation. The derived amplitude is seen to contain no exponential suppression or enhancement. Coments on the CFT description of the process are made.
15707893
Strategies to identify boosted tops
We study techniques for identifying highly boosted top jets, where the subsequent top decay products are not isolated. For hadronic boosted tops, we consider variables which probe the jet substructure in order to reduce the background from QCD jets with large invariant mass. Substructure variables related to two-body kinematics are least sensitive to the modeling of parton shower, while those which involve multi-body kinematics may still have discrimination power. For leptonic boosted tops, we consider variables which characterize the separation between the lepton—although not isolated by conventional criterion—and the hadronic activity in the top jet. Such variables are useful in reducing the backgrounds both from heavy-flavor jets and from accidental jet-lepton overlap. We give numerical estimates of the top identification efficiency versus background rejection rate as a functions of cuts on these variables, and find that these variables offer additional useful information above invariant mass alone.
51830179
Identifying boosted objects with N-subjettiness
We introduce a new jet shape — N-subjettiness — designed to identify boosted hadronically-decaying objects like electroweak bosons and top quarks. Combined with a jet invariant mass cut, N-subjettiness is an effective discriminating variable for tagging boosted objects and rejecting the background of QCD jets with large invariant mass. In efficiency studies of boosted W bosons and top quarks, we find tagging efficiencies of 30% are achievable with fake rates of 1%. We also consider the discovery potential for new heavy resonances that decay to pairs of boosted objects, and find significant improvements are possible using N-subjettiness. In this way, N-subjettiness combines the advantages of jet shapes with the discriminating power seen in previous jet substructure algorithms.
14278021
Locality in theory space
A bstractLocality is a guiding principle for constructing realistic quantum field theories. Compactified theories offer an interesting context in which to think about locality, since interactions can be nonlocal in the compact directions while still being local in the extended ones. In this paper, we study locality in “theory space”, four-dimensional Lagrangians which are dimensional deconstructions of five-dimensional Yang-Mills. In explicit ultraviolet (UV) completions, one can understand the origin of theory space locality by the irrelevance of nonlocal operators. From an infrared (IR) point of view, though, theory space locality does not appear to be a special property, since the lowest-lying Kaluza- Klein (KK) modes are simply described by a gauged nonlinear sigma model, and locality imposes seemingly arbitrary constraints on the KK spectrum and interactions. We argue that these constraints are nevertheless important from an IR perspective, since they affect the four-dimensional cutoff of the theory where high energy scattering hits strong coupling. Intriguingly, we find that maximizing this cutoff scale implies five-dimensional locality. In this way, theory space locality is correlated with weak coupling in the IR, independent of UV considerations. We briefly comment on other scenarios where maximizing the cutoff scale yields interesting physics, including theory space descriptions of QCD and deconstructions of anti-de Sitter space.