Dennis Silverman

Exploring new physics with CP asymmetries in B0 decays

Abstract CP asymmetries in B0 decays into CP eigenstates are shown to be very useful in probing effects of new physics. Although there are many possible sources for inconsistencies with the Standard Model predictions, we find that various relations among the asymmetries test different aspects of new physics. We suggest a new way to test the assumption that the direct decays are dominated by a single combination of mixing parameters. We argue that new physics in K − K mixing is unlikely to affect the results. New physics in the mixing of B d − B d and B s − B s can be probed separately and independently of the unitarity of the CKM matrix.

Magnetic Moments of Composite Fermions

Abstract There have been a considerable number of papers proposing composite models for leptons and quarks. Recently, Gluck and Lipkin have stated that reproducing the observed magnetic moments of these fermions presents a serious difficulty for these composite models. We show for a renormalizable theory that, in contrast to Glucks and Lipkins nonrelativistic arguments, a deeply bound system (with heavy constituent particle masses mc) of (total) spin 1 2 , charge e and mass m has the magnetic moment (e/2m) [1 + “usual” (QED + QCD + weak) corrections +O (m/m c ) “new” bindng corrections] . Although there remains the considerable dynamical problem of obtaining “light” bound fermions from heavy constituents, there is no separate, additional magnetic moment difficulty.

Multiperipheral dynamics and inclusive experiments

SummaryThe relationship between multiperipheral dynamics and inclusive experiments at high energy is developed. The general features of the single-particle distribution spectrum are exhibited for multiperipheral models with exponential damping in the momentum transfers. By working with a specific multi-Regge model we further demonstrate the phenomena of pionization and of scaling in longitudinal momentum for small momentum transfers. Examples of distribution spectra are given for specific and physically important values of Regge parameters. The predictions can serve as a test for a realistic model for the integral-equation approach to multiperipheral dynamics, and can provide a sensible form for parametrizing experimental data.RiassuntoSi sviluppa la relazione fra la dinamica multiperiferica e i relativi esperimenti ad alta energia. Si riportano le caratteristiche generali della distribuzione di singole particelle per i modelli multiperiferici con smorzamento esponenziale dell’impulso trasferito. Lavorando con un specifico modello di Regge multiplo si dimostrano inoltre i fenomeni di pionizzazione e di scala dell’impulso longitudinale per piccoli impulsi trasferiti. Si danno esempi degli spettri di distribuzione per valori specifici e fisciamente importanti dei parametri di Regge. Le predizioni possono servire come verifica per un modello realisitico per l’approccio con l’equazione integrale alla dinamica multiperiferica, e possono fornire una formula attendibile per parametrizzare i dati sperimentali.РеэюмеВыводится соотнощение между много-периферической динамикой и включаюшими зкспериментами при высоких знергиях. Выявляются обшие особенности спектра распределения отдельной частицы для много-периферических моделей с зкспоненциальным эатуханием относительно передаваемого импульса. Работая со специальной множественной моделью Редже, мы, кроме того, отмечаем явления пиониэации и подобия относительно продольного импульса для малых передаваемых импульсов. Приводятся примеры спектров распределения для специальных и фиэически важных эначений параметров Редже. Эти предскаэания могут служить как проверка реалистической модели для подхода на основе интегральных уравнений к много-периферической динамике, и могут обеспечивать раэумную форму для параметриэации зкспериментальных данных.

Associative recall properties of the trion model of cortical organization

We developed a cooperative model of the cortical column incorporating an idealized subunit, the trion (which represents a localized group of neurons), and a discrete time step for firing. We found that networks composed of a small number of trions (with symmetric interactions) supported up to thousands of quasi-stable, periodic firing patterns (MPs) which could be selected out with only small changes in interaction strengths using a Hebb-type algorithm. Here we report a study of the associative recall properties showing striking features: By considering all possible initial firing patterns (for a given set of network connections), we find 1) It takes on the average only 2–5 time steps to recall an MP. 2) Many of the MPs can be individually accessed by thousands of different initial patterns. The variety of examples presented illustrate the rich, general nature of the model.

Trion model of cortical organization: Toward a theory of information processing and memory

In the spirit of Mountcastle’s [1] organizational principle for neocortical function, and strongly motivated by Fisher’s [2] model of physical spin systems, we have introduced [3] a new cooperative mathematical model of the cortical column. Our model incorporates an idealized substructure, the trion, which represents a localized group of neurons. The trion model allows for a completely new framework for information processing and associative memory storage and recall: Small networks of trions with highly symmetric interactions are found to yield hundreds to thousands of quasi-stable, periodic firing patterns, MP’s, which can evolve from one to another (see Fig. 1). Experience or learning would then modify the interactions (away from the symmetric values) and select out the desired MP’s (as in the selection principle of Edelman [4]). Remarkably, we have found that relatively small modifications in trion interaction strengths (away from the symmetric values) via a Hebb-type algorithm [5] will enhance and select out any desired MP. Conceptually this suggests a radically different approach from those information processing models which start at the opposite extreme of a randomly connected neural network with no periodic firing patterns, and then (via Hebb-type modifications [5] in the synaptic interactions) reinforce specific firing patterns. More recently [6], in studying the associative recall properties of the networks we find that, on the average, any of the initial firing configurations rapidly (in 2 to 4 time steps) projects onto an MP.

Full range of predictions for B physics from isosinglet down quark mixing

We extend the range of predictions of the isosinglet (or vector) down quark model to the fully allowed physical ranges, and also update this with the effect of new physics constraints. We constrain the present allowed ranges of sin(2{beta}) and sin(2{alpha}), {gamma}, x{sub s}, and A{sub B{sub s}}. In models allowing mixing to a new isosinglet down quark (as in E{sub 6}) flavor changing neutral currents are induced that allow a Z{sup 0} mediated contribution to B{minus}{bar B} mixing and which bring in new phases. In ({rho},{eta}), {bold (}x{sub s},sin({gamma}){bold )}, and (x{sub s},A{sub B{sub s}}) plots for the extra isosinglet down quark model which are herein extended to the full physical range, we find new allowed regions that will require experiments on sin({gamma}) and/or x{sub s} to verify or to rule out an extra down quark contribution. {copyright} {ital 1998} {ital The American Physical Society}

B factory constraints on isosinglet down quark mixing, and predictions for other CP violating experiments

In the main part of this paper we project forward to having B factory determinations of sin(2β) and sin(2α), for which we take several values. First, we use a joint χ2 analysis of CKM experiments to constrain CKM matrix elements in the standard model, and experiments on the angles a, β and γ, and on xs and null CP asymmetries. Then we invoke mixing to a new isosinglet down quark (as in E6) which induces FCNC’s that allow a Z0 mediated contribution to mixing and which brings in new phases. We then repeat the χ2 analysis, now including experimental constraints from FCNC’s as well, finding much larger ranges of prediction for the B factory. We then add projected B factory results on sin(2β) and sin(2α) and repeat both analyses. In (ρ, η) and (xs, sin(γ)) plots for the extra isosinglet down quark model, we find multiple regions that will require experiments on sin(γ) and/or xs to decide between, and possibly to effectively bound out the extra down quark contribution.

Flavor changing neutral processes and Bd0−B̄d0 mixing☆

Abstract We propose that the observed B d 0 −B d 0 mixing reported by ARGUS and CLEO is due to the tree-level flavor changing neutral coupling of the standard model Higgs scalar, H 0 , or the Z 0 , induced by new physics with a mass scale beyond the standard model. The strengths of the flavor changing couplings of H 0 and Z 0 are shon to be increasing with the masses of the fermion flavors involved. If the observed B d 0 -B d 0 mixing is due to the flavor changing coupling of H 0 , the key predictions are D D 0 -D 0 mixing of O (10%) of the present experimental upper limit and BR(μ − a e − γ) ≅ (1.1 ± 0.6) × 10 −12 , and the mass of the Higgsscalar M H ≅(200–300) GeV. In case the observed B d 0 - B d 0 mixing is due to the flavor changing coupling of Z 0 , the rare decay mode μ − ae − e + e − is predicted to be observable at any time in the near future with the branching ratio in the neighborhood of the present experimental upper limit, while other predictions include: D 0 -D 0 mixing of O(1–10)% of the present upper limit, BR(B s 0 a μ + μ − X) ≅ (8.5 ± 4.2) × 10 −5 , BR(τ t- a μ − μ+μ − ) ≅ (8.8 ±4.8) × and the branching ratios for the flavor changing decay modes of Z 0 , BR(Z 0 abs + ss) × 10 7 ≅ (14 ±7), BR (Z 0 a tc + ct) × 10 7 ± (1500 ± 700)( m t /60 GeV ), BR(Z 0 a b′b +bb′) × 10 7 ≅ (4800 ± 2300)( m b /50 GeV), BR (Z 0 a μ − τ + + μ + τ − ) × 3.6 ± 1.8, and BR (Z 0 a τ′ τ + τ′τ) × 10 7 ≅ (1300 ± 600) ( m τ /40 GeV). These flavor changing branching ratios of Z 0 can be tested at LEP with 10 7 Z 0 ′s. From the observed strength of B d 0 -B d 0 mixing the scale of new physics can be inferred to be M ≅ 250 GeV.

The decay proton → e+γ in grand unified gauge theories

Author(s): Silverman, D; Soni, A | Abstract: The rate for proton decay to the e+γ mode is calculated. Although its branching ratio is of order α, its ratio to observable e+π0 correlated decays is 1 8 to 1 40. Observable numbers of p → e+ + γ decays can occur and would provide constraints on the proton wave function at the origin and grand unified parameters independent of hadron final state uncertainties.

RELATIVISTIC TREATMENT OF QUARKONIUM IN QCD

Abstract We have formulated a relativistic two-body equation for quark-antiquark bound states using the expansion in intermediate states. We have used the asymptotically free QCD gluon exchange with either a scalar or equal vector and scalar linear potential. Using these we have fitted the upsilon, charmonium, D, F, s s , s -u, d and u, d quark mesons for the rho and above. We have also calculated relativistically their widths, singlet-triplet and P-state splittings.