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Harry J. Lipkin

Publications and source records attributed to Harry J. Lipkin.

At least 73 records · Page 4Linked to original sources
arXiv2001

Systematics of Large Axial Vector Meson Production in Heavy Flavor Weak Decays

Branching ratios observed for $D$ and B decays to final states $a_1(1260)^{\pm} X$ are comparable to those for corresponding decays to $π^{\pm} X$ and $ρ^{\pm} X$ and much larger than those for all other decays. Implications are discussed of a "vector-dominance model" in which a $W$ is produced and immediately turns into an axial vector, vector or pseudoscalar meson. Data for decays to all such final states are shown to have large branching ratios and satisfy universality relations. Upper limits on small strong phase differences between amplitudes relevant to CP violation models are obtained from analysis of the predicted and observed suppression of $B^o$ decays into neutral final states $π^o X^o$, $ρ^oX^o$ and $a_1^o X^o$. . Branching ratios of $\approx 1%$ are predicted for the as yet unobserved presence of the $D_{s1}(2536)$ charmed-strange axial vector in B decays.

hep-ph↗
arXiv2001

Weak decays to final states with Radial Excitation Admixtures

We consider the weak decays of a B meson to final states that are mixtures of S-wave radially excited components. We consider non leptonic decays of the type $B \to ρ' π/B \to ρπ$, $B \to ω' π/B \to ωπ$ and $B \to ϕ' π/B \to ϕπ$ where $ρ'$, $ω'$ and $ϕ'$ are higher $ρ$, $ω$ and $ϕ$ resonances. We find such decays to have larger or similar branching ratios compared to decays where the final state $ρ$, $ω$ and $ϕ$ are in the ground state. We also study the effect of radial mixing in the vector and the pseudoscalar systems generated from hyperfine interaction and the annihilation term. We find the effects of radial mixing to be small and generally negligible for all practical purposes in the vector system. However, in the $η-η^{\prime}$ system the effects of radial mixing are appreciable and seriously affect decay branching ratios for $B \to η(η')K(K^*)$. In particular we find that nonstandard $η(η')$ mixing can resolve the puzzles in $B \to η(η')K$ decays.

hep-ph↗
arXiv1999

Neutrino oscillations as a "which-path" experiment

The role of simple quantum mechanics in understanding neutrino oscillation experiments is pointed out by comparison with two-slit and Bragg scattering experiments. The importance of considering the beam and the detector as a correlated quantum system is emphasized. Quantum mechanics alone shows that the difference observed in the same neutrino detector at Super-Kamiokande between upward and downward going neutrinos requires the existence of a neutrino mass difference. The localization of the source and detector in space in the laboratory system for long times leads to an uncertainty in the momentum but not of the energy of the neutrino and to coherence between states having different momenta and the same energy and not between states with different energies.

hep-ph↗
arXiv1999

The New $σ_{tot}(Σp)$ Data, the new PDG fit to hadron total cross sections and the TCP alternative

The new SELEX measurement $σ_{tot}(Σp) = 36.96 \pm 0.65$ at P = 609 GeV/c and the new 1998 Particle-Data-Group Regge (PDG) analysis of hadron total cross sections with an additional even-signature-exchange contribution recall the 1975 two-component-Pomeron model (TCP), which introduced such an additional term and predicted $σ_{tot}(Σp) = 37.07$ mb. in 1975 as well as fitting all the same data now fit by PDG with fewer free parameters.and predicting $σ_{tot}(Σp)$, (not predicted by PDG) at lower energies. The additional contribution confuses the extraction of the Pomeron intercept from data in the 600 GeV range and its dynamical origin is still unclear. But its surprising systematics suggests an interesting origin.

hep-ph↗
arXiv1999

Theoretical Analysis of Static Hyperon Data for HYPERON99

We consider all hyperon data relevant to spin and flavor structure of hyperons. In addition to masses and magnetic moments considered as static properties in Hyperon99 we include also relevant data from hyperon decays and spin structure determined from deep inelastic scattering. Any theoretical model for the hyperons with parameters to be determined from experiment should use input from all these data. Of particular interest are new data from $Ξ^o$ decay and the polarixation of $Λ's$ produced in Z^o decays and deep inelastic scattering.

hep-ph↗
arXiv1999

Theoretical Summary of the HADRON99 conference

The Constituent Quark Model has provided a remarkable description of the experimentally observed hadron spectrum but still has no firm theoretical basis. Attempts to provide a QCD justification discussed at Hadron99 include QCD Sum Rules, instantons, relativistic potential models and the lattice. Phenomenological analyses to clarify outstanding problems like the nature of the scalar and pseudoscalar mesons and the low branching ratio for $ψ' \to ρ-π$ were presented. New experimental puzzles include the observation of $\bar p p \to ϕπ$.

hep-ph↗
arXiv1999

Nucleon Spin with and without Hyperon Data: A New Tool for Analysis

We present a simple explanation of the underlying physics in the use of hyperon decay data to obtain information about proton spin structure. We also present an alternative input using nucleon magnetic moment data and show that the results from the two approaches are nearly identical. The role of symmetry breaking is clarified while pointing out that simple models explaining the violation of the Gottfried sum rule via pion emission tend to lose the good SU(3) predictions from Cabibbo theory for hyperon decays.

hep-ph↗
arXiv1999

Isospin Invariance and Generalized Bose Statistics applied to Low Energy $K^{+-}K^0$ and $π^{+-}π^0$ Space Symmetries

The use of isospin invariance and Generalized Bose statistics shows that the Bose-Einstein correlation (BEC) of identical bosons seen in the $K^+K^+$ and $π^+ π^+$ systems can be extended to apply to $K^+ K^o$ and $π^+ π^o$ pairs when they are produced from an initial state with isospin zero; e.g. by the fragmentation of gluons or of a strange quark pair accompanied by gluons. This might be useful in constructing more realistic model dependent Monte Carlo programs for the investigation of the isospin structure of the particles produced in a given kinematic region like the central region in high energy hadronic collisions or quark-gluon plasma. Some of the consequences of this extension are here applied to the hadronic $Z^o$ decays. In particular the study addresses the question how much of the observed low $K^o_S K^o_S$ mass enhancement is to be attributed to a BEC effect and how much to the $f_0(980)\to K^o_S K^o_S$ decay. Finally we point out the restrictions imposed by the extension on the choice of reference samples for the BEC studies.

hep-ph↗
arXiv1999

Flavor Symmetry, K^0-\bar{K}^0 Mixing and New Physics Effects on CP Violation in D^{\pm} and D^{\pm}_s Decays

Flavor symmetry and symmetry breaking, K^0-\bar{K}^0 mixing and possible effects of new physics on CP violation in weak decay modes D^{\pm} \to K_{S,L} + X^{\pm}, (K_{S,L} + π^0)_{K^*} + X^{\pm} (for X =π, ρ, a_1) and D^{\pm}_s \to K_{S,L} + X^{\pm}_s, (K_{S,L} +π^0)_{K^*} + X^{\pm}_s (for X_s = K, K^*) are analyzed. Relations between D^{\pm} and D^{\pm}_s decay branching ratios are obtained from the d \Leftrightarrow s subgroup of SU(3) and dominant symmetry-breaking mechanisms are investigated. A CP asymmetry of magnitude 3.3\times 10^{-3} is shown to result in the standard model from K^0-\bar{K}^0 mixing in the final-state. New physics affecting the doubly Cabibbo-suppressed channels might either cancel this asymmetry or enhance it up to the percent level. A comparison between the CP asymmetries in D^{\pm}_{(s)} \to K_{S} X^{\pm}_{(s)} and D^{\pm}_{(s)} \to K_L X^{\pm}_{(s)} can pin down effects of new physics.

hep-ph↗
arXiv1999

Implications of Isospin Conservation in $Λ_b$ Decays and Lifetime

We consider isospin predictions for the semi-leptonic and non-leptonic decays of the $Λ_b$ baryon. Isospin conservation of the strong interactions constrains the possible final states in $Λ_b$ decays. Since the baryon hyperfine splittings depend upon light quark dynamics and do not decrease with increasing heavy quark mass, this leads in general to to phase space enhancements in $Λ_b$ decays relative to $B$ meson decays for the same underlying quark transitions. Consequently the $Λ_b$ lifetime is smaller than the $B$ lifetime. Phase space enhancements in $Λ_b$ decays relative to $B$ decays can be understood in terms of hyperfine interactions in the heavy quark system.

hep-ph↗
arXiv1999

Quantum Mechanics of Neutrino Oscillations - Hand Waving for Pedestrians

Why Hand Waving? All calculations in books describe oscillations in time. But real experiments don't measure time. Hand waving is used to convert the results of a "gedanken time experiment" to the result of a real experiment measuring oscillations in space. Right hand waving gives the right answer; wrong hand waving gives the wrong answer. Many papers use wrong handwaving to get wrong answers. This talk explains how to do it right and also answers the following questions: 1. A neutrino which is a mixture of two mass eigenstates is emitted with muon in the decay of a pion at rest. This is a a "missing mass experiment" where the muon energy determines the neutrino mass. Why are the two mass states coherent? 2. A neutrino which is a mixture of two mass eigenstates is emitted at time t=0. The two mass eigenstates move with different velocities and arrive at the detector at different times. Why are the two mass states coherent? 3. A neutrino is a mixture of two overlapping wave packets with different masses moving with different velocities. Will the wave packets eventually separate? If yes, when?

hep-ph↗
arXiv1998

Search for New Physics in $D^\pm \to K_S X^{\pm} $ and $D^\pm \to K_S K_S K^{\pm}$

Direct CP violation beyond the standard model can be produced in charged D decays to final states with a $K_S$ by small new physics contributions to the transitions $D^+ \to K^o X^+$, where $X^+$ denotes any positively charged hadronic state or transitions $D^+ \to K^o \bar K^o K^{(*)+}$, where $K^{(*)+}$ denotes any positive strange state. These transitions are doubly-Cabibbo suppressed and color suppresed in the standard model and branching ratios are experimentally observed to be suppressed by two orders of magnitude relative to the allowed $D^+ \to \bar K^o X^+$ or $D^+ \to \bar K^o \bar K^o K^{(*)+}$, branching ratio. An even smaller new physics contribution might produce an observable CP asymmetry in $D^\pm \to K_S X^\pm$ or $D^{\pm} \to K_S K_S K^{(*)\pm}$ decays. Since such asymmetries are easily checked in the early stages of any charm production experiment, it seems worth while to check them before the opportunity is lost in later stages of the analysis, even if no theoretical model predicts such an asymmetry.

hep-ph↗
arXiv1998

A useful approximate isospin equality for charmless strange B Decays

A useful inequality is obtained if charmless strange B decays are assumed to be dominated by a $ΔI = 0$ transition like that from the gluonic penguin diagram and the contributions of all other diagrams including the tree, electroweak penguin and annihilation diagrams are small but not negligible. The interference contributions which are linear in these other amplitudes are included but the direct contributions which are quadratic are neglected.

hep-ph↗
arXiv1998

A useful approximate isospin equality for charmless strange B Decays

A useful inequality is obtained if charmless strange B decays are assumed to be dominated by the gluonic penguin diagram and the tree diagram contribution is small but not negligible. The penguin-tree interference contribution which is linear in the tree amplitude is included but the direct tree contribution which is quadratic is neglected.

hep-ph↗
arXiv1998

FSI Rescattering in $B^\pm$ Decays via States with $η, η', ω$ and $ϕ$

New results going beyond those obtained from isospin and flavor symmetry and subject to clear experimental tests are obtained for effects of FSI in $B^\pm$ decays to charmless strange final states containing neutral flavor-mixed mesons like $ω$, $ϕ$, $η$ and $η'$. The most general strong-interaction diagrams containing arbitrary numbers of quarks and gluons are included with the assumptions that any $q \bar q$ pair created by gluons must be a flavor singlet, and that there are no hairpin diagrams in which a final meson contains a $q \bar q$ pair from the same gluon vertex. The smallness of $K^- η$ suggests that it might have a large CP violation. A sum rule is derived to test whether the large $K^- η'$ requires the addition of an additional glueball or charm admixture. Further analysis from $D_s$ decay systematics supports this picture of FSI and raises questions about charm admixture in the $η'$.

hep-ph↗
arXiv1998

Pentaquark Update After Ten Years

Studying scattering of heavy flavor hadrons and looking for bound states is shown to give experimental information otherwise unobtainable about effective two-body interactions between constituent $(qq)_6$ and $(\bar qq)_8$ pairs respectively in color sextet and color octet states. All the successes of the constituent quark model in $(uds)$ hadron spectroscopy are shown to depend only on effective two-body interactions in color $3^*$ and singlet states. New directions for bound pentaquark searches are discussed following the availability of vertex detectors which can pinpoint events where a proton is emitted from a secondary vertex. Any such event indicates a particle decaying weakly by proton emission and the discovery of a new particle if its mass is higher than that of known charmed baryons. There is no combinatorial background and striking decay signatures like $p ϕπ^-$ are no longer needed. The beauty pentaquark ($\bar b suud$) and the doubly-strange pentaquark ($\bar c ssud$) may be relevant to future searches. A simple calculation shows that the effects of flavor-SU(3) breaking on their binding relative to the relevant thresholds are similar to that for the singly-strange pentaquark ($\bar c suud$) relative to the $D_s p$ threshold.

hep-ph↗
arXiv1998

Soft FSI Systematics for charmless strange $B^\pm$ Decays

New results going beyond those obtained from isospin and flavor symmetry and subject to clear experimental tests are obtained for effects of FSI in $B^\pm$ decays to final states containing neutral flavor-mixed mesons like $ω$, $ϕ$, $η$ and $η'$. The most general strong-interaction diagrams containing arbitrary numbers of quarks and gluons are included with the assumptions that any $q \bar q$ pair created by gluons must be a flavor singlet, and that there are no hairpin diagrams in which a final meson contains a $q \bar q$ pair from the same gluon vertex. The smallness of $K^- η$ suggests that it might have a large CP violation. A sum rule is derived to test whether the large $K^- η'$ requires the addition of an additional glueball or charm admixture. Further analysis from $D_s$ decay systematics supports this picture of FSI and raises questions about charm admixture in the $η'$.

hep-ph↗