Frank C. Porter

Global CKM Fits with the Scan Method

We present results of unitary triangle fits based on the scan method. This frequentist approach employs Gaussian uncertainties for experimental quantities, but avoids assumptions about the distribution of theoretical errors. Instead, we perform a large number of fits, scanning over regions of plausible theory errors for each quantity. We retain those fits meeting a specific confidence level criterion, thereby constructing a region in the ρ¯−η¯ plane using the “standard” measurements (Cabibbo-Kobayashi-Maskawa matrix elements, sin2β, B0d,s mixing, eK). In addition we use branching fraction and CP asymmetry measurements of B decays to pseudoscalar pseudoscalar, pseudoscalar vector, vector vector, and a1 pseudoscalar final states to determine α, D(*)K(*) modes to determine γ, and D(*)π and Dρ modes to determine 2β+γ. We parametrize individual decay amplitudes in terms of color-allowed tree, color-suppressed tree, penguin, singlet penguin, electroweak penguin, as well as W-exchange and W-annihilation amplitudes. With this parametrization, we obtain a good fit to the measured branching fractions and CP asymmetries within the standard model ansatz, with no new physics contributions. This simultaneous fit allows us to determine, for the first time in a global fit, the correlation between α and β, as well as between γ and β.

Interval estimation using the likelihood function

Abstract The general properties of two commonly-used methods of interval estimation for population parameters in physics are examined. Both of these methods employ the likelihood function: (i) Obtaining an interval by finding the points where the likelihood decreases from its maximum by some specified ratio; (ii) Obtaining an interval by finding points corresponding to some specified fraction of the total integral of the likelihood function. In particular, the conditions for which these methods give a confidence interval are illuminated, following an elaboration on the definition of a confidence interval. The first method, in its general form, gives a confidence interval when the parameter is a function of a location parameter. The second method gives a confidence interval when the parameter is a location parameter. A potential pitfall of performing a likelihood analysis without understanding the underlying probability distribution is discussed using an example with a normal likelihood function.

The new narrow “Ds” states – A minireview

The experimental status concerning the two new narrow states with charm-strange content is reviewed. The states have masses of 2317 and 2460 MeV, widths less than 10 MeV, isospin consistent with zero, and spin-parities consistent with being 0+ and 1+, respectively. Although the masses are lower than the conventional expectation, these states appear to be the j=1/2 P-wave levels of the Ds system, where j is the light quark angular momentum; there may be mixing with the j=3/2 level for the 1+ state.PACS: 14.40.Lb Charmed mesons – 13.66.Bc Hadron production in e-e+ interactions

Experimental status of the CKM matrix

The CKM matrix, V, relates the quark mass and flavor bases. In the standard model, V is unitary 3X3, and specified by four arbitrary parameters, including a phase allowing for

15. Ensemble Learning

CP

Luminosity lifetime at an asymmetric e+e− collider☆

violation. We review the experimental determination of V, including the four parameters in the standard model context. This is an active field; the precision of experimental measurements and theoretical inputs continues to improve. The consistency of the determination with the standard model unitarity is investigated. While there remain some issues the overall agreement with standard model unitarity is good.

Review of Caltech Workshop and Some Parametric Questions for a High‐Luminosity Asymmetric B‐Factory Collidera

This chapter gives a tutorial introduction to Ensemble Learning, a recently developed Bayesian method. For many problems it is intractable to perform inferences using the true posterior density over the unknown variables. Ensemble Learning allows the true posterior to be approximated by a simpler approximate distribution for which the required inferences are tractable.

Toponium Physics in e+ e‐ Collisions

Abstract The dependence of the luminosity on time is discussed for an asymmetric e + e − storage ring collider, with emphasis on single-particle scattering mechanisms for beam loss. The “optimal” filling strategy and average luminosity obtainable are also reviewed.

Finding the Top Quark at the SLAC Linear Collider with the Mark II Experimenta

The potential to probe the Standard Model and beyond with studies in the B-meson system has resulted in the investigation of techniques to perform this physics. One of the most promising is to produce the Υ(4S) resonance, moving in the laboratory frame, using an e^+e^- storage-ring collider with different energies in the two beams. In April 1989, a workshop was held at Caltech to investigate the issues involved in designing such an accelerator. I summarize the results of that workshop in this paper: and also investigate some parametric questions incorporating several of the constraints discussed there. The purpose of the Caltech Workshop was to consider the accelerator physics issues faced in attempting to achieve a high-luminosity (ℒ ~ 10^(34) cm^(-2) s^(-1)) asymmetric e^+e^- storage-ring B-factory in the E_(cm) ≈ 10-GeV region. There were four working groups, chosen to address what were perceived to be the most difficult areas: (1) beam-beam limitations, (2) optics, (3) beam current limitations, and (4) small beam pipe at the interaction point (IP). I summarize the conclusions from each of these groups in the following sections. Many of these considerations apply as well to symmetric B-factory colliders.

Finding a rational nomenclature for mesons and baryons

Given the enormous productivity of experiments looking at charmonium and bottomonium states produced in e+ecollisions, it is important to investigate the possibilities for toponium physics.’ Three toponium mass regions can be distinguished in this discussion: (i) While the evidence mounts against the possibility that me < m,, it is perhaps premature to dismiss it. If me < m,, then there is a rich physics program to be carried out, even with relatively small data sets. One indication of this richness is the existence of several important decay modes in this region (FIGURE 1). Two significant decay modes that are not important for the lower-mass onia are the weak single quark decays (SQD) of toponium and the 0 Z * v; decays. (ii) It also is possible that m, = m,. In this case, a striking interference yielding very sharp dips and peaks in the Z o peak is Unfortunately, radiative processes and machine energy spread largely wash out the effect, for example, as shown for the SLC beam width in FIGURE 2 . It will be difficult, though not impossible, to see this effect. However, the smaller energy spread of LEP will be an asset. Because of the mixing with the Zo, the dominant decay is 0 fJ; where f (for “fermion”) is a quark or lepton. Several of the physics topics to be discussed are not enhanced by the mixing with the Zo and, hence, the backgrounds are much more severe in this region. (iii) Finally, it is quite likely that m, > mZ. As can be seen in FIGURE 1, the weak SQD toponium decays quickly dominate and the toponium width depends on mass approximately as mi f ( m i / 4 m k ) for 2mb << me < 2mw, where’