Factorization in the Production and Decay of the X(3872)

The production and decay of the X(3872) are analyzed under the assumption that the X is a weakly-bound molecule of the charm mesons D^0 \bar D^{*0} and D^{*0} \bar D^0. The decays imply that the large D^0 \bar D^{*0} scattering length has an imaginary part. An effective field theory for particles with a large complex scattering length is used to derive factorization formulas for production rates and decay rates of X. If a partial width is calculated in a model with a particular value of the binding energy, the factorization formula can be used to extrapolate to other values of the binding energy and to take into account the width of the X. The factorization formulas relate the rates for production of X to those for production of D^0 \bar D^{*0} and D^{*0} \bar D^0 near threshold. They also imply that the line shape of X differs significantly from that of a Breit-Wigner resonance.Comment: 23 pages, 8 figures, revtex4, typos correcte

Pion Interactions in the X(3872)

We consider pion interactions in an effective field theory of the narrow resonance X(3872), assuming it is a weakly bound molecule of the charm mesons D^{0} \bar D^{*0} and D^{*0} \bar D^{0}. Since the hyperfine splitting of the D^{0} and D^{*0} is only 7 MeV greater than the neutral pion mass, pions can be produced near threshold and are non-relativistic. We show that pion exchange can be treated in perturbation theory and calculate the next-to-leading-order correction to the partial decay width \Gamma[X \to D^0 \bar D^{0} \pi^0].Comment: 26 pages, 11 figures, revtex4, to appear in Phys. Rev.

Production of the X(3872) in B Meson Decay by the Coalescence of Charm Mesons

If the recently-discovered charmonium state X(3872) is a loosely-bound S-wave molecule of the charm mesons \bar D^0 D^{*0} or \bar D^{*0} D^0, it can be produced in B meson decay by the coalescence of charm mesons. If this coalescence mechanism dominates, the ratio of the differential rate for B^+ \to \bar D^0 D^{*0} K^+ near the \bar D^0 D^{*0} threshold and the rate for B^+ \to X K^+ is a function of the \bar D^0 D^{*0} invariant mass and hadron masses only. The identification of the X(3872) as a \bar D^0 D^{*0}/\bar D^{*0} D^0 molecule can be confirmed by observing an enhancement in the \bar D^0 D^{*0} invariant mass distribution near the threshold. An estimate of the branching fraction for B^+ \to X K^+ is consistent with observations if X has quantum numbers J^{PC} = 1^{++} and if J/\psi \pi^+ \pi^- is one of its major decay modes.Comment: 4 pages, 3 figures, revtex

Quahogs in Eastern North America: Part II, History by Province and State

The northern quahog, Mercenaria mercenaria, ranges along the Atlantic Coast of North America from the Canadian Maritimes to Florida, while the southern quahog, M. campechiensis, ranges mostly from Florida to southern Mexico. The northern quahog was fished by native North Americans during prehistoric periods. They used the meats as food and the shells as scrapers and as utensils. The European colonists copied the Indians treading method, and they also used short rakes for harvesting quahogs. The Indians of southern New England and Long Island, N.Y., made wampum from quahog shells, used it for ornaments and sold it to the colonists, who, in turn, traded it to other Indians for furs. During the late 1600’s, 1700’s, and 1800’s, wampum was made in small factories for eventual trading with Indians farther west for furs. The quahoging industry has provided people in many coastal communities with a means of earning a livelihood and has given consumers a tasty, wholesome food whether eaten raw, steamed, cooked in chowders, or as stuffed quahogs. More than a dozen methods and types of gear have been used in the last two centuries for harvesting quahogs. They include treading and using various types of rakes and dredges, both of which have undergone continuous improvements in design. Modern dredges are equipped with hydraulic jets and one type has an escalator to bring the quahogs continuously to the boats. In the early 1900’s, most provinces and states established regulations to conserve and maximize yields of their quahog stocks. They include a minimum size, now almost universally a 38-mm shell width, and can include gear limitations and daily quotas. The United States produces far more quahogs than either Canada or Mexico. The leading producer in Canada is Prince Edward Island. In the United States, New York, New Jersey, and Rhode Island lead in quahog production in the north, while Virginia and North Carolina lead in the south. Connecticut and Florida were large producers in the 1990’s. The State of Tabasco leads in Mexican production. In the northeastern United States, the bays with large openings, and thus large exchanges of bay waters with ocean waters, have much larger stocks of quahogs and fisheries than bays with small openings and water exchanges. Quahog stocks in certified beds have been enhanced by transplanting stocks to them from stocks in uncertified waters and by planting seed grown in hatcheries, which grew in number from Massachusetts to Florida in the 1980’s and 1990’s

Simple test for high Jc and low Rs superconducting thin films

A simple method, fishing high-Tc superconductor thin films out of liquid nitrogen bath by a permanent magnet (field > Hc1) due to the effect of high flux pinning, has been suggested to identify films having high critical current density (Jc > 106 A/cm2 at 77 K) and thus a low microwave surface resistance (Rs). We have demonstrated that a Nd-Fe-B magnet, having a maximum field of ~ 0.5 T, could fish out Tl-1223 superconducting thin films on LSAT substrate with a thickness of ~ 5000 Angstrong having Jc > 1 MA/cm2 (at 77 K) whereas it could not fish out other films with Jc < 0.1 MA/cm2 at 77 K. The fished out films exhibit Rs values 237 - 245 ((at 77 K and 10 GHz, which is lower than that (Rs = 317 (() of the best YBCO film at the same temperature and frequency. On the other hand, the non-fishable films show very high Rs values. This method is a very simple tool to test for high Jc and good microwave properties of superconducting films of large area which otherwise require a special and expensive tool.Comment: 5 pages including 2 figures, to be published as Rapid Commun. in Supercond. Sci. Techno

Intimate Relationship Dynamics and Changing Desire for Pregnancy Among Young Women

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151900/1/psrh12119_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151900/2/psrh12119.pd

Black-White Differences in Pregnancy Desire During the Transition to Adulthood

This article explores race differences in the desire to avoid pregnancy or become pregnant using survey data from a random sample of 914 young women (ages 18-22) living in a Michigan county and semi-structured interviews with a subsample of 60 of the women. In the survey data, desire for pregnancy, indifference, and ambivalence are very rare but are more prevalent among Black women than White women. In the semi-structured interviews, although few women described fatalistic beliefs or lack of planning for future pregnancies, Black and White women did so equally often. Women more often described fatalistic beliefs and lack of planning when retrospectively describing their past than when prospectively describing their future. Using the survey data to compare prospective desires for a future pregnancy with women\u27s recollections of those desires after they conceived, more Black women shifted positive than shifted negative, and Black women were more likely to shift positive than White women-that is, Black women do not differentially retrospectively overreport prospectively desired pregnancies as having been undesired before conception. Young women\u27s consistent (over repeated interviews) prospective expression of strong desire to avoid pregnancy and correspondingly weak desire for pregnancy, along with the similarity of Black and White women\u27s pregnancy plans, lead us to conclude that a planning paradigm -in which young women are encouraged and supported in implementing their pregnancy desires-is probably appropriate for the vast majority of young women and, most importantly, is similarly appropriate for Black and White young women