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Harry J. Lipkin

Publications and source records attributed to Harry J. Lipkin.

88 records · Page 5Linked to original sources
arXiv1997

Hyperfine Interactions in Charm and Bottom Systems

Hyperfine interactions in the light meson and baryon sectors are generalized to the charm and bottom systems. It is pointed out that an attempt to increase the value of the wave function at the origin to account for the unusual ratio of $Λ_{b}$ to the $B^0$ lifetimes could spoil the good agreement among the baryon and meson hyperfine mass-splitting. Including spin effects and taking phase space differences into account we predict that the decay rate of the $Λ_{b}$ can be increased relative to that of the $B^0$ meson by about 7%.

hep-ph↗
arXiv1996

Flavor Oscillations from a Spatially Localized Source: A Simple General Treatment

A unique description avoiding confusion is presented for all flavor oscillation experiments in which particles of a definite flavor are emitted from a localized source. The probability for finding a particle with the wrong flavor must vanish at the position of the source for all times. This condition requires flavor-time and flavor-energy factorizations which determine uniquely the flavor mixture observed at a detector in the oscillation region; i.e. where the overlaps between the wave packets for different mass eigenstates are almost complete. Oscillation periods calculated for ``gedanken'' time-measurement experiments are shown to give the correct measured oscillation wave length in space when multiplied by the group velocity. Examples of neutrinos propagation in a weak field and in a gravitational field are given. In these cases the relative phase is modified differently for measurements in space and time. Energy-momentum (frequency-wave number) and space-time descriptions are complementary, equally valid and give the same results. The two identical phase shifts obtained describe the same physics; adding them together to get a factor of two is double counting.

hep-ph↗
arXiv1996

A Simple General Treatment of Flavor Oscillations

A unique description avoiding confusion is presented for all flavor-oscillation experiments in which particles of a definite flavor are emitted from a localized source. The probability for finding a particle with the wrong flavor must vanish at the position of the source for all times. This condition requires flavor-time and flavor-energy factorizations which determine uniquely the flavor mixture observed at a detector in the oscillation region; i.e. where the overlaps between the wave packets for different mass eigenstates differ negligibly from 100\%. The translation of a ``gedanken'' experiments calculations (where measurement is perform in time) is done using the {\it group} velocity. Energy-momentum (frequency-wave number) and space-time descriptions are complementary, equally valid and give the same results. The two identical phase shifts obtained describe the same physics; adding them together to get a factor of two is double counting.

hep-ph↗
arXiv1995

Angular distributions and lifetime differences in $B_s \to J/ψϕ$ decays

The strange $B$ meson $B_s \equiv \bar b s$ and its charge-conjugate $\bar B_s \equiv b \bar s$ are expected to mix with one another in such a way that the mass eigenstates $B_s^H$ (``heavy'') and $B_s^L$ (``light'') may have a perceptible lifetime difference of up to 40\%, with the CP-even eigenstate being shorter-lived. A simple transversity analysis permits one to separate the CP-even and CP-odd components of $B_s \to J/ψϕ$, and thus to determine the lifetime difference. The utility of a similar analysis for $B^0 \to J/ψK^{*0}$ is noted.

hep-ph↗
arXiv1995

A Strong QCD Enhancement of CP Violation in Charmed Meson Decays?

The mass difference of $c$ and $u$ quarks is similar to the energy needed to excite gluonic degrees of freedom in strong QCD. This underpins the degeneracy of $D$ and a recently observed candidate hybrid excitation of the $π$ at$\sim 1.8$GeV and may generate a strong analogue of Penguin mixing together with a measurable CP-violation in $D$ and $D_s$ decays.

hep-ph↗
arXiv1995

Spin Contents of Nucleons with SU(3) Breaking

We apply a model for SU(3) breaking to the analysis of the spin contents of the nucleon from the the latest data on first moments of the spin dependent structure functions and include higher order QCD corrections. The results show that the value of the total quark spin contribution to the nucleon spin $ΔΣ\equiv Δu + Δd +Δs$ remains about 0.3 and is very insensitive to SU(3) breaking, while the result for the strange quark contribution varies considerably with SU(3) breaking.

hep-ph↗
arXiv1995

Theories of Non-Experiments in Coherent Decays of Neutral Mesons

Many theoretical calculations of subtle coherent effects in quantum mechanics do not carefully consider the interface between their calculations and experiment. Calculations for gedanken experiments using initial states not satisfied in realistic experiments give results requiring interpretation. Confusion and ambiguities frequently arise. Calculations for time-dependent mixing oscillations describe non-experiments. Physical experiments describe oscillations in space in the laboratory system resulting from interference between waves having the same energy and time dependence; $not$ different momenta and space dependence. Time-dependent oscillations are not observed.

hep-ph↗
arXiv1994

How to Use Weak Decays in Analyses of Data on Nucleon Spin Structure Functions

The use of weak decays to determine proton spin structure is examined in view of possible violations of the Bjorken and Gottfried Sum rules, flavor symmetry breaking and flavor asymmetry in the sea. The use of the neutron decay is found to be unaffected by all these. A method for including these effects in analyses of hyperon decays shows that a flavor-asymmetric sea produced by SU(3) symmetry breaking has only a small effect on results for the total spin carried by quarks. However the strange quark contribution cannot be reliably obtained from charged lepton scattering and weak decay data alone, and requires additional model-dependent input relating nucleon and hyperon wave functions.

hep-ph↗
arXiv1993

A Symmetry Approach to CP Violation

One of the greatest challenges for particle physics in the 1990's is understanding the broken symmetry of CP violation. It is now almost 30 years since the discovery in 1964 of the $K_{L} \rightarrow 2π$ decay. What has happened since? Why has there been no significant new experimental input in this long period? The original $K_{L} \rightarrow 2π$ decay experiment is described by two parameters $ε$ and $ε'$. Today $ε\approx $ its 1964 value while $ε'$ still consistent with zero, and there is no new evidence for CP violation outside the kaon system. Why is it so hard to find CP violation? How can B Physics Help? We present a symmetry approach to these questions.

hep-ph↗
arXiv1993

Ideas on charm and beauty decays

The parton model, a zero-order approximation in many treatments, is shown to be a ``semiclassical" model whose results for certain averages also hold (correspondence principle) in quantum mechanics. Algebraic techniques developed for the Mössbauer effect exploit simple features of commutators to obtain sum rules showing the validity of the parton model for $b \rightarrow c$ semileptonic decays in the classical limit, $\hbar \rightarrow 0$, where all commutators vanish, and in general, even when binding effects are included, for the lowest moments of the lepton energy spectrum at fixed 3-momentum transfer. Interference between the $u \bar u$ and $d \bar d$ components of the $ρ^o$ and $ω$ wave functions can be used as clues to contributions from small weak amplitudes and CP violation in decays to final states including these vector mesons.

hep-ph↗
arXiv1993

A QCD Relation Between Hyperfine Splittings in Isospin doublets - A Light Quark Symmetry?

Recent data on the $D^*$ masses confirm the QCD prediction based on the \REF{\ICHJL}{Isaac Cohen and Harry J. Lipkin, \plb{84}{323}{1979}} very general assumption $\({\ICHJL}\)$ that the spin-dependence of the quark couplings to photons and gluons have the same structure and differ only in the value of the coupling constants, This prediction with no free parameters and using the $Ξ$ and $Ξ^*$ masses as input follows from noting that the charmed antiquark $\bar c$ and the strange diquark (ss) have exactly the same couplings to both the photon (Q=-2/3) and to the gluon (both are color antitriplets). New predictions are obtained with this approach. Corrections to the naive model are investigated and shown to be small.

hep-ph↗
arXiv1993

Application of Mössbauer-Type Sum Rules for $B$ Meson Decays

Sum rules originally derived for the Mössbauer Effect are applied to weak semileptonic B decays. The sum rules follow from assuming that the decay by electroweak boson emission of an unstable nucleus or heavy quark in a bound system is described by a pointlike coupling to a current which acts only on the decaying object, that the Hamiltonian of the bound state depends on the momentum of the decaying object only in the kinetic energy and that the boson has no final state interactions. The decay rate and the first and second moments of the boson energy spectrum for fixed momentum transfer are shown to be the same as for a noninteracting gas of such unstable objects with a momentum distribution the same as that of the bound state. B meson semileptonic decays are shown to be dominated by the lowest-lying states in the charmed meson spectrum.

hep-ph↗
arXiv1993

Quark Models and Quark Phenomenology

Overwhelming experimental evidence for quarks as real physical constituents of hadrons along with the QCD analogs of the Balmer Formula, Bohr Atom and Schroedinger Equation already existed in 1966. A model of colored quarks interacting with a one-gluon-exchange potential explained the systematics of the meson and baryon spectrum and gave a hadron mass formula in surprising agreement with experiment. The simple quark model dismissed as heresy and witchcraft by the establishment predicted quantum numbers of an enormous number of hadronic states as well as relations between masses, reaction cross sections and electromagnetic properties, all unexplained by other approaches. Further developments leading to QCD included confinement in the large $N_c$ limit, duality, dual resonance and string models, high energy scattering systematics, unified treatment of mesons and baryons, no exotics and no free quarks.

hep-ph↗
arXiv1993

Implications of $τ$ Decays into Strange Scalar and Axial Vector Mesons

Recent reports of the observation of the decay $τ\rarrow ν_τ + K + π+ π$ raise interesting questions. The $u-s$ quark mass difference can induce an effective second-class current in the strange sector and enhance decays to helicity-suppressed scalar states. This suggests searches for scalar strange mesons in the $τ\rarrow ν_τ + K + η' $ and $τ\rarrow ν_τ + K + π$ decay modes. $τ$ decays to axial vector final states may clarify strange meson spectroscopy by analogy with the clarification of the $a_1$ problem in the nonstrange sector. Open questions include mixing effects in the strange axial vector mesons and the implications of models based on QCD for hadronization and final state interactions following the creation of a $q \bar q$ pair by a weak vertex,

hep-ph↗
arXiv1992

Bose-Einstein Correlations for Mixed Neutral Mesons

Correlations are shown to arise in nonidentical mixed-particle pairs like $K^o \bar K^o$ when observed in identical decay modes like $K_S K_S$ in multiparticle final states containing many partial waves. No enhancement is found in any single partial wave and all partial wave analyses of the s-wave threshold resonance $a_o$ and $f_o$ should give the same results for all decay modes. In CP violation experiments where $B^o - \bar B^o$ pairs are inclusively produced and correlated decays into $ψK_S$ and leptonic modes are observed, the CP-violating lepton asymmetry is enhanced by a factor of two in the kinematic region where Bose enhancement occurs.

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