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Experiments are done by colliding a swinging bat with a stationary baseball or softball. Each collision was recorded with high-speed cameras, from which the post-impact speed, launch angle, and spin of the ball could be determined. Initial bat speeds were in the range 63-88 mph, producing launch angles in the range 0$^\circ$-30$^\circ$ and spins in the range 0-3500 rpm. The results are analyzed in the context of a ball-bat collision model and the parameters of that model are determined. For both baseballs and softballs, the data are consistent with a mechanism whereby the ball grips the surface of the bat, stretching the ball in the transverse direction and resulting in a spin that was up to 40$\%$ greater than would be obtained by rolling contact of rigid bodies. Using a lumped parameter contact model, baseballs are shown to be less compliant tangentially than softballs. Implications of our results for batted balls in game situations are presented., Comment: Accepted for American Journal of Physics, 22 pages, 10 figures, 2 tables

Past work has shown large variation in the drag of baseballs. Little is known concerning the causes of variation in ball drag. Ball diameter, weight, seam height, surface roughness, and shape influence lift and drag, and therefore carry distance. The aim of this work was to quantify the effect of seam height and roundness on ball lift and drag, which, to our understanding, has never been done outside of a wind tunnel. A bespoke, non-contact, ball surface profiler, was used to measure ball radius, including seam height. The profiles were analyzed to describe ball roundness and seam height separately. Balls with three different seam heights were projected in an enclosed stadium 102-122 m (describing a typical fly ball). Redundant radar devices were used to measure launch angle, speed, and flight paths. High speed video was used to confirm launch angle and ball spin rate. Hit distance was verified with a physical tape measure. The ball's roundness influenced the effective height of a seam. Measurements of the non-seam area of a ball were necessary to characterize the seams of a ball. A strong correlation was observed between seam height and a ball's drag coefficient. Lift, however, was not sensitive to seam height or ball shape.

A description is given of the upgraded photon tagging facility at the MAX IV Laboratory. Two magnetic spectrometers are used to momentum analyze post-bremsstrahlung electrons. The tagged photon range extends from 10 to 180 MeV with an energy resolution of about 300 keV. The system has been operated at rates up to 4×106 photons s-1 MeV −1. Different diagnostic tools are described as well as the experimental program.

The electric and magnetic polarizabilities of the proton are now well known, owing to Compton scattering measurements on hydrogen targets; however, the neutron polarizabilities are still relatively uncertain, compared to the proton values. To address this problem, a multiinstitutional collaboration has conducted a program of elastic Compton scattering experiments on deuterium at the MAX IV Laboratory in Lund, Sweden using tagged photons in the energy range Eγ= 65-115 MeV. We assembled at one laboratory, for the first time, three of the world's largest NaI detectors, each having better than ΔE/E ∼ 2% photon energy resolution. We have measured elastic Compton scattering cross sections at lab angles of θγ= 60°, 120° and 150° over this energy range in 8 MeV steps. This effectively doubles the world's set of elastic Compton scattering data from deuterium and provides valuable input for chiral effective field theory (χEFT) calculations. These new deuterium data overlap previous measurements and extend them by 20 MeV to higher energies. Based on χEFT fits to the expanded world data set, new values for the neutron electric and magnetic polarizabilities have been obtained with greater accuracy than previously achieved, decreasing the statistical error by more than 30%. (Less)

The results of a comparative study of five aluminum and one wood baseball bats are presented. The study includes an analysis of field data, high-speed laboratory testing, and modal analysis. It is found that field performance is strongly correlated with the ball–bat coefficient of restitution (BBCOR) and only weakly correlated with other parameters of the bat, suggesting that the BBCOR is the primary feature of a bat that determines its field performance. It is further found that the instantaneous rotation axis of the bat at the moment of impact is very close to the knob of the bat and that the rotational velocity varies inversely with the moment of inertia of the bat about the knob. A swing speed formula is derived from the field data and the limits of its validity are discussed. The field and laboratory measurements of the collision efficiency are generally in good agreement, as expected on theoretical grounds. Finally, the BBCOR is strongly correlated with the frequency of the lowest hoop mode of the hollow bats, as predicted by models of the trampoline effect.

The classic experiment to measure the drag coefficient involves dropping coffee filters.1 Wouldn't it be more fun to try something different? In fact, an experiment on the drag force is conducted nearly 4000 times a day during the baseball season and you have free access to this PITCHf/x data!2

An apparatus is described for measuring the stiffness and coefficient of restitution (COR) of balls with application to softballs. While standardized test methods currently exist to measure these properties, they do not represent the displacement rate and magnitude that occur in play. The apparatus described herein involves impacting a fixed, solid cylindrical surface (matched to the diameter of the bat) with a ball and measuring the impact force during impact and speed of the ball before and after impact. The ratio of the ball speeds determines the COR, while the impact force is used to derive a ball stiffness. For an example of the contribution of the new ball test, the performance of hollow bats, which is sensitive to ball stiffness, was compared. Bat performance showed a much stronger dependence on the proposed ball stiffness than the traditional measure. Finally, it was shown that to achieve similar conditions between impacts with fixed and recoiling objects, the impact speed should be chosen so that the centre of mass energy was the same in the two cases. The method has application to associations wishing an improved method to regulate ball and bat performance.

A new program of Compton scattering on deuterium is under way at the tagged-photon facility at MAX-Lab in Lund, Sweden. We will measure differential cross sections between 60A degrees and 150A degrees over the photon energy range 60-115 MeV in 5 MeV steps, with the ultimate goal of obtaining new precision information on the electric and magnetic polarizabilities of the neutron.

Even professional baseball players occasionally find it difficult to gracefully approach seemingly routine pop-ups. This paper describes a set of towering pop-ups with trajectories that exhibit cusps and loops near the apex. For a normal fly ball, the horizontal velocity is continuously decreasing due to drag caused by air resistance. But for pop-ups, the Magnus force (the force due to the ball spinning in a moving airflow) is larger than the drag force. In these cases the horizontal velocity decreases in the beginning, like a normal fly ball, but after the apex, the Magnus force accelerates the horizontal motion. We refer to this class of pop-ups as paradoxical because they appear to misinform the typically robust optical control strategies used by fielders and lead to systematic vacillation in running paths, especially when a trajectory terminates near the fielder. In short, some of the dancing around when infielders pursue pop-ups can be well explained as a combination of bizarre trajectories and misguidance by the normally reliable optical control strategy, rather than apparent fielder error. Former major league infielders confirm that our model agrees with their experiences.

New measurements are presented of the lift on a spinning baseball for speeds in the range 50–110 mph and spins 1500–4500 rpm. The experiment utilizes a pitching machine to project the baseball horizontally; a high-speed motion capture system to measure the initial velocity and angular velocity and to track the trajectory over ∼5 m of flight; and a ruler to measure the total distance traversed by the ball. The lift coefficients are extracted from the data and compared to with previous measurements or parametrizations.

The gear effect arises when a ball collides with an object and the object recoils with a component of its acceleration in a direction parallel to the two contacting surfaces. Two experiments are described that show how the surfaces of the ball and the object can engage without slip similar to two gears. The effect is used in golf to correct for off-center impacts and it plays a minor role in baseball.

Differential cross sections for elastic scattering of photons from the deuteron have recently been measured at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. These first new measurements in more than a decade further constrain the isoscalar electromagnetic polarizabilities of the nucleon and provide the first-ever results above 100 MeV, where the sensitivity to the polarizabilities is increased. We add 23 points between 70 and 112 MeV, at angles 60deg, 120deg and 150deg. Analysis of these data using a Chiral Effective Field Theory indicates that the cross sections are both self-consistent and consistent with previous measurements. Extracted values of \alpha_s = [12.1 +/- 0.8(stat) +/- 0.2(BSR) +/- 0.8(th)] X 10^{-4} fm^3 and \beta_s = [2.4 +/- 0.8(stat) +/- 0.2(BSR) +/- 0.8(th)] X 10^{-4} fm^3 are obtained from a fit to these 23 new data points. This paper presents in detail the experimental conditions and the data analysis used to extract the cross sections., Comment: 13 pages, 8 figures, to be submitted to Physical Review C

The electromagnetic polarizabilities of the nucleon are fundamental properties that describe its response to external electric and magnetic fields. They can be extracted from Compton-scattering data --- and have been, with good accuracy, in the case of the proton. In contradistinction, information for the neutron requires the use of Compton scattering from nuclear targets. Here we report a new measurement of elastic photon scattering from deuterium using quasimonoenergetic tagged photons at the MAX IV Laboratory in Lund, Sweden. These first new data in more than a decade effectively double the world dataset. Their energy range overlaps with previous experiments and extends it by 20 MeV to higher energies. An analysis using Chiral Effective Field Theory with dynamical \Delta(1232) degrees of freedom shows the data are consistent with and within the world dataset. After demonstrating that the fit is consistent with the Baldin sum rule, extracting values for the isoscalar nucleon polarizabilities and combining them with a recent result for the proton, we obtain the neutron polarizabilities as \alpha_n = [11.55 +/- 1.25(stat) +/- 0.2(BSR) +/- 0.8(th)] X 10^{-4} fm^3 and \beta_n = [3.65 -/+ 1.25(stat) +/- 0.2(BSR) -/+ 0.8(th)] X 10^{-4} fm3, with \chi^2 = 45.2 for 44 degrees of freedom., Comment: 6 pages, 3 figures, comments from Physical Review Letters Referees addressed

The E99-114 experiment was carried out to measure the cross sections for Real Compton Scattering (RCS) on the proton in the kinematic range s = 5 − 11 GeV 2 , − t = 2 − 7 GeV 2 . In addition, a measurement of longitudinal and transverse polarization transfers was made at s = 6.9 GeV 2 and − t = 4.0 GeV 2 . These measurements were done to test the existing theoretical mechanisms for this process and will possibly lead to the determination of RCS form factors which are related to the Generalized Parton Distributions (GPD). The experiment was conducted in Hall A of Thomas Jefferson National Accelerator Facility (Jefferson Lab). Final results of polarization transfer measurements are presented.

The characterization of the performance of baseball bats is presented from a physics point of view. The goal is to define a set of laboratory measurements that can be used to predict performance in the field. The concept of a model-independent collision efficiency, which relates the post-collision ball speed to the initial ball and bat speeds, is introduced and its properties are investigated. It is shown to provide a convenient link between laboratory and field measurements. Other performance metrics are presented, related to the collision efficiency, and evaluated according to their predictive power. Using a computational model, it is shown that bat performance depends on the interplay of the elasticity of the ball–bat collision, the inertial properties of the ball and bat, and the bat swing speed. It is argued that any method of determining performance needs to take all of these factors into account. A new method is proposed and compared with commonly used existing methods.

Elastic scattering of photons from C-12 has been investigated using quasimonoenergetic tagged photons with energies in the range 65-115 MeV at laboratory angles of 60 degrees, 120 degrees, and 150 degrees. at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. A phenomenological model was employed to provide an estimate of the sensitivity of the C-12(gamma,gamma)C-12 cross section to the bound- nucleon polarizabilities.

A model is developed for the collision between the baseball and bat, taking into account the transverse bending vibrations of the bat. By coupling the flexible bat to the ball via a parametrized force that each mutually exerts on the other, a complete description of the collision process is obtained, including the exit speed of the ball vf. It is shown that vibrations play an important role in determining vf. The model is in excellent agreement with experimental data at low impact velocities. At the higher velocities more appropriate to the game of baseball, vf is shown to coincide with the rigid-body value only over a very small region in the barrel of the bat and to drop off sharply for impacts removed from that region. Some interesting insights into the collision process are obtained, including the observation that for impacts in the barrel of the bat, the momentum transferred to the ball is essentially complete by the time the elastic wave first arrives at the handle and that any clamping action of th...

A review is presented of the elastic photon scattering data from the proton at energies below 150 MeV, where the important physics to be learned is the electric and magnetic polarizabilities of the proton. The relationship between the polarizabilities and the Compton scattering cross section is established. The experimental data are reviewed. Techniques for extracting the polarizabilities from the data are discussed and then used to obtain new values. Particular attention is paid to the theoretical uncertainty in this procedure. A brief theoretical review is given with the principal emphasis on dispersion relations.

Spin-polarised atomic hydrogen is used as a gaseous polarised proton target in high energy and nuclear physics experiments operating with internal beams in storage rings. When such beams are intense and bunched, this type of target can be depolarised by a resonant interaction with the transient magnetic field generated by the beam bunches. This effect has been studied with the HERA positron beam in the HERMES experiment at DESY. Resonances have been observed and a simple analytic model has been used to explain their shape and position. Operating conditions for the experiment have been found where there is no significant target depolarisation due to this effect., REVTEX, 6 pages, 5 figures

The first measurements of the differential cross section for the d(gamma,p)n reaction up to 4.0 GeV were performed at Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. We report the cross sections at the proton center-of-mass angles of 36, 52, 69 and 89 degrees. These results are in reasonable agreement with previous measurements at lower energy. The 89 and 69 degree data show constituent-counting-rule behavior up to 4.0 GeV photon energy. The 36 and 52 degree data disagree with the counting rule behavior. The quantum chromodynamics (QCD) model of nuclear reactions involving reduced amplitudes disagrees with the present data., Comment: 5 pages (REVTeX), 1 figure (postscript)

The (e,e'p) reaction was studies on targets of C, Fe, and Au at momentum transfers squared Q{sup 2} of 0.6, 1.3, 1.8 and 3.3 GeV{sup 2} in a region of kinematics dominated by quasifree electron-proton scattering. Missing energy and missing momentum distributions are reasonably well described by plane wave impulse approximation calculations with Q{sup 2} and A dependent corrections that measure the attenuation of the final state protons.

Rate-dependent effects in the electronics used to instrument the tagger focal plane at the MAX IV Laboratory have been investigated using the novel approach of Monte Carlo simulation. Results are compared to analytical calculations as well as experimental data for both specialized testing and production running to demonstrate a thorough understanding of the behavior of the detector system., Comment: 31 pages, 17 figures, modified after submission to Nuclear Instruments and Methods in Physics Research Section A

Angular distributions for photon scattering from {sup 12}C and {sup 4}He have been measured using continuous wave bremsstrahlung from the Saskatchewan Accelerator Laboratory pulse stretcher ring. Data for carbon were taken at 158.8, 195.2, 197.2, 247.2, and 290.2 MeV end-point energies, and for helium were taken at an end-point energy of 158.8 MeV. A large NaI(Tl) gamma ray spectrometer with 1.7% resolution was used to detect the scattered photons at laboratory scattering angles ranging from 20{degree} to 150{degree}. The excellent energy resolution of the NaI detector allowed a separation of elastic from inelastic photon scattering for the first time at these energies. The angular distributions for elastic scattering are in only fair agreement with delta-hole theory and theory based on the optical theorem at forward angles, and completely disagree with theory at backward angles. Measured cross sections for inelastic scattering leading to the 4.43 MeV state in carbon are small compared to the elastic scattering at forward angles, but are dominant at backward angles. This experiment is the first to separate elastic from inelastic photon scattering at these energies.

We measured the $^{4}\mathrm{He}$(\ensuremath{\alpha},\ensuremath{\gamma}) cross section at ${\mathrm{\ensuremath{\theta}}}_{\ensuremath{\gamma}}$=90\ifmmode^\circ\else\textdegree\fi{} across the 16.6 and 16.9 MeV resonances in $^{8}\mathrm{Be}$ and obtained angular distributions on the peaks of both resonances. The decays of the 16 MeV doublet to the 3.0 MeV ${2}^{+}$ final state have an (isovector E2)/(isovector M1) mixing ratio of (0.01\ifmmode\pm\else\textpm\fi{}0.03), an (isoscalar E2)/(isovector M1) mixing ratio of (0.21\ifmmode\pm\else\textpm\fi{}0.04), and an isovector M1 width of (2.80\ifmmode\pm\else\textpm\fi{}0.18) eV. Our result for the isovector E2 strength disagrees markedly with previous work. We observe ground-state E2 decays of both members of the doublet. We use our results, plus existing $^{8}\mathrm{Li}$ and $^{8}\mathrm{B}$ \ensuremath{\beta}-decay data, to test the conservation of the vector current and to constrain the second-class induced-tensor form factor. Finally, we compare our results to shell-model calculations.

The intense, nearly monoenergetic, 100% polarized $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}$-ray beams available at the $\mathrm{HI}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}\mathrm{S}$ facility, along with the realization that the $E1\mathrm{\text{\ensuremath{-}}}E2$ interference term that appears in the Compton scattering polarization observable has opposite signs in the forward and backward angles, make it possible to obtain an order-of-magnitude improvement in the determination of the parameters of the isovector giant quadrupole resonance (IVGQR). Accurate IVGQR parameters will lead to a more detailed knowledge of the symmetry energy in the nuclear equation of state which is important for understanding nuclear matter under extreme conditions such as those present in neutron stars. Our new method is demonstrated for the case of $^{209}\mathrm{Bi}$.

The proton Compton effect has been studied in the region between the threshold for pion photoproduction and the \ensuremath{\Delta}(1232). The measurements were performed using bremmstrahlung from the high duty-factor electron beam available at the Saskatchewan Accelerator Laboratory. Elastically scattered photons were detected with an energy resolution of approximately 1.5% using a large NaI total absorption scintillation detector. Differential cross sections were measured for photon energies in the range 136 MeV\ensuremath{\le}${\mathit{E}}_{\ensuremath{\gamma}}$\ensuremath{\le}289 MeV and for angles in the range 25\ifmmode^\circ\else\textdegree\fi{}${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$135\ifmmode^\circ\else\textdegree\fi{}. The angular distributions and the excitation functions derived from these data are in agreement with recent theoretical analyses. The results were interpreted within a formalism based in part on dispersion relations to obtain model-dependent estimates of the electric and magnetic polarizabilities, \ensuremath{\alpha}\ifmmode\bar\else\textasciimacron\fi{} and \ensuremath{\beta}\ifmmode\bar\else\textasciimacron\fi{}. We find, subject to the dispersion sum rule constraint \ensuremath{\alpha}\ifmmode\bar\else\textasciimacron\fi{}+\ensuremath{\beta}\ifmmode\bar\else\textasciimacron\fi{}=(14.2\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$ ${\mathrm{fm}}^{3}$, that \ensuremath{\alpha}\ifmmode\bar\else\textasciimacron\fi{}=(9.8\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}1.1)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$ ${\mathrm{fm}}^{3}$ and \ensuremath{\beta}\ifmmode\bar\else\textasciimacron\fi{}=(4.4\ensuremath{\mp}0.4\ensuremath{\mp}1.1)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$ ${\mathrm{fm}}^{3}$, which are consistent with the best previous measurements.

We develop closed-form expressions for the cross section for the electromagnetic excitation induced by heavy-ion collisions at intermediate and high energies. These expressions directly relate the excitation cross section to the corresponding photonuclear cross section. The effects of strong absorption, relativity and retardation are incorporated from the outset and are shown to be important. We apply our results to several situations of recent interest, including the excitation and photon decay of giant resonances.

Three separate questions of relevance to Major League Baseball are investigated from a physics perspective. First, can a baseball be hit farther with a corked bat? Second, is there evidence that the baseball is more lively today than in earlier years? Third, can storing baseballs in a temperature- or humidity-controlled environment significantly affect home run production? Each of these questions is subjected to a physics analysis, including an experiment, an interpretation of the data, and a definitive answer. The answers to the three questions are no, no, and yes., Comment: 8 pages, 9 figures

We report the first exclusive ({gamma},{pi}{sup {minus}}{ital p}) measurements on a complex nucleus. The {sup 16}O({gamma},{pi}{sup {minus}}{ital p}) reaction was measured at pion laboratory angles of 64{degree} and 120{degree}. Coincident protons were detected over the quasifree angular correlation range using a vertical array of seven plastic scintillator detectors spanning {plus minus}33{degree} about the scattering plane. The cross sections are compared to factorized distorted-wave impulse approximation calculations; these provide a good description of the backward angle data, but are in serious disagreement with the forward angle data.

Elastic photon scattering cross sections have been measured on {sup 4}He in the region of the giant dipole resonance (GDR) using the tagged-photon technique. These data place stringent constraints on the total photoabsorption {sigma}{sub {gamma}} at the peak of the GDR, which to very good approximation is the sum of the ({gamma},{ital p}) and ({gamma},{ital n}) cross sections. We find the peak cross section to be {sigma}{sub 0}=2.86{plus minus}0.12 mb. This result is inconsistent with the sum of the most recent measurements of the ({gamma},{ital p}) and ({gamma},{ital n}) cross sections. Thus any conclusion about charge symmetry based on the ratios of these cross sections is suspect.

The first measurements of elastic photon scattering on complex nuclei from 150 MeV to the Δ(1232) (Eγ = 300 MeV) are compared with theoretical calculations. Data on 4He at the Δ peak are in agreement with a Δh calculation, but substantial disagreement occurs at lower energies that is at least partly due to the approximate treatment of non-resonant parts of the elementary nucleon amplitude. An impulse approximation calculation which includes meson exchange provides an adequate description of the data at 187 MeV on 4He. Improved data on the proton at 20–30° and 120–140° at a range of energies are in agreement with a recent dispersion relation calculation. Data taken on 12C are still too preliminary to report, due to the difficulty of eliminating inelastic contributions.

We derive an expression relating the photon-scattering cross section to the photoabsorption cross section, taking into account the underlying compound nuclear levels. This formalism provides for the first time a framework for the analysis of photon-scattering data that is valid for arbitrary width-to-level-spacing ratios of the compound nuclear levels. When applied to a giant resonance, the formalism leads to a ground-state photon branching ratio which is significantly different from that used to interpret recent Coulomb excitation experiments.

The angular distributions for coherent photon scattering from {sup 4}He were measured at average laboratory bremsstrahlung energies of 187, 235, and 280 MeV. The experiment was performed at the Saskatchewan Accelerator Laboratory using the new high duty factor electron beam. The scattered photons were observed with a high-resolution NaI(Tl) total absorption scintillation detector. These measurements are intended to investigate modification of the {Delta} properties inside the nuclear medium and the treatment of nonresonant contributions to the scattering cross sections. The results are compared to theoretical calculations in the isobar-hole model. Clear deviations from the theory are evident at all energies, especially at 187 MeV.

The high-energy continuum from inelastic scattering of 84 MeV/nucleon {sup 17}O by {sup 208}Pb was studied by measuring {sup 17}O--{gamma}-ray coincidences. The particle spectra in coincidence with {gamma} rays above {similar to}1 MeV show structures up to 45-MeV excitation energy that can be explained in terms of the statistical decay of the highly excited target nucleus. The observation in the {gamma}-ray spectrum of the giant dipole resonance built on excited states in {sup 208}Pb confirms that the continuum up to {similar to}60-MeV excitation energy is dominated by the excitation of {sup 208}Pb and offers the unique possibility of detailed studies of the giant dipole resonance as a function of excitation energy decoupled from the influence of angular momentum.

In this contribution we discuss an experimental program that is planned at I l l ino is to investigate elastic photon scattering on few-nucleon systems at energies between about 40 MeV and the pion threshold. These energies are large compared with typical energies of collective nuclear excitations but small compared with energies of nucleon excitations. In this regime we expect the photon scattering amplitude to be dominated by the coherent superposition of scattering amplitudes from the individual charges and magnetic moments that make up the nuclear system. Neglecting the lat ter contribution, the photon scatters primarily from individual protons and from interacting neutron-proton pairs, as shown schematically in Figure 1. These we Call (a) the one-body and (b) the two-body contributions to the scattering amplitude, respectively.

We have measured the angular and mass distributions of the fragments from photofission of {sup 238}U using tagged photons with energies between 11 and 16 MeV. The fission fragments were detected by a 4{pi} arrangement of position-sensitive parallel-plate avalanche counters. Anisotropic angular distributions have been observed for the first time in the energy range where second-chance fission becomes energetically possible. A consistent assignment of {ital J}{sup {pi}} and {ital K} for the fission channels in {sup 237}U has been deduced from a combined analysis of ({gamma},{ital nf}) and ({ital e},{ital e}{prime}{ital f}) data. A clear relationship between the anisotropies and the fragment mass asymmetry has also been established. This correlation, together with the energy dependence of the angular distribution parameters, points to a possible interpretation of the results in terms of a recent theoretical model incorporating multiple exit channels in fission.

We have investigated the excitation and ground-state photon decay of the giant resonance region in {sup 208}Pb and {sup 209}Bi due to inelastic scattering of 84 MeV/nucleon {sup 17}O. The inelastic spectra are dominated by the isovector giant dipole resonance. The spectra of {sup 208}Pb and {sup 209}Bi are almost identical in the giant resonance region. We conclude that the resonance strength functions are very nearly the same for these nuclei. Significant differences are, however, found in the distribution of ground-state decay photons from the two nuclei. These differences appear to be due to a large contribution from decay of fully damped compound states in {sup 208}Pb.

Nuclear resonance fluorescence experiments have been performed on the nuclei 142,146,148,150 Nd, which are located in the mass region of a nuclear shape transition from a spherical ( 142 Nd) to a well-deformed shape ( 150 Nd). Bremsstrahlung of 4.1 MeV endpoint energy served as the photon source. The scattered photons were detected by high-resolution Ge-spectrometers. Precise excitation energies, decay branching ratios, and ground-state decay widths of numerous new spin-1 states have been extracted.

Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s = 5-11 and -t = 2-7 GeV2 with statistical accuracy of a few percent. The scaling power for the s-dependence of the cross section at fixed center of mass angle was found to be 8.0 +/ 0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross-section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark., 5 pages, 5 figures

A ball can be hit faster if it is projected without spin but it can be hit farther if it is projected with backspin. Measurements are presented in this paper of the tradeoff between speed and spin for a baseball impacting a baseball bat. The results are inconsistent with a collision model in which the ball rolls off the bat and instead imply tangential compliance in the ball, the bat, or both. If the results are extrapolated to the higher speeds that are typical of the game of baseball, they suggest that a curveball can be hit with greater backspin than a fastball, but by an amount that is less than would be the case in the absence of tangential compliance., Comment: Accepted for publication in American Journal of Physics

Five papers specifically dealing with the science or engineering of baseball were submitted to the conference. Four of these papers deal with topics associated with issues related to the ball-bat collision. The fifth paper deals with the aerodynamics of a baseball in flight. All of the submitted papers address issues of practical importance to the game of baseball. What follows is a brief summary of each paper, followed by a synopsis of other activity in the field not reported at this conference.

We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 distinct kinematic settings covering a range in momentum transfer of 0.4

The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.

A separation of the longitudinal and transverse 12 C(e, e8p) cross sections in the quasifree region has been performed in parallel kinematics at Q 2 of 0.64 and 1.8 GeV 2 for initial proton momentum ,80 MeV. The separated transverse and longitudinal spectral functions at Q 2 50.64 GeV 2 show significant differences for missing energy between 25 and 60 MeV indicating a breakdown in the single nucleon knockout picture. The transverse spectral functions exhibit definite momentum transfer dependence.