Here, we compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial-wave analysis, applied to the photoproduction of pseudoscalar mesons. The approach is ...pedagogical, showing in detail how the amplitude reconstruction (observables measured at a single energy and angle) is related to a truncated partial-wave analysis (observables measured at a single energy and a number of angles).
We consider the problems associated with amplitude extraction, from meson photoproduction data, over the first resonance regions. The notion of a complete experiment has motivated the FROST program ...at Jefferson Lab. Exercises applied to pion photoproduction data illustrate the problems to be confronted in any attempt to extract underlying resonance signals from these data (without introducing a model for the resonant process).
Exclusive and kinematically complete high-statistics measurements of quasifree polarized np scattering have been performed in the energy region of the narrow resonancelike structure d* with I(JP) = ...0(3 super(+)), M approximately 2380 MeV, and Gamma approximately 70 MeV observed recently in the double-pionic fusion channels pn arrow right dpi super(0)pi super(0) and pn arrow right dpi super(+)pi super(-). The experiment was carried out with the WASA detector setup at COSY having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dp arrow right np + p sub(spectator). This allowed the np analyzing power, A sub(y) to be measured over a broad angular range. The obtained A sub(y)angular distributions deviate systematically from the current SAID SP07 NN partial-wave solution. Incorporating the new A sub(y)data into the SAID analysis produces a pole in the super(3)D sub(3) - super(3)G sub(3) waves in support of the d* resonance hypothesis.
Review of Particle Physics
The European physical journal. C, Particles and fields,
03/1998, Letnik:
3, Številka:
1-4
Journal Article
Recenzirano
Odprti dostop
This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 1600 new measurements from 550 papers, we list, evaluate, and average measured properties of gauge ...bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http: //pdg. lbl. gov.
The proton–proton elastic differential cross section at very small four momentum transfer squared has been measured at three different incident proton momenta in the range of 2.5 to 3.2 GeV/c by ...detecting the recoil proton at polar angles close to 90∘. The measurement was performed at COSY with the KOALA detector covering the Coulomb–nuclear interference region. The total cross section σtot, which has been determined precisely, is consistent with previous measurements. The values of the slope parameter B and the relative real amplitude ratio ρ determined in this experiment alleviate the lack of data in the relevant energy region. These precise data on ρ might be an important check for a new dispersion analysis.
Baryon resonance analysis from SAID Arndt, R. A; Briscoe, W. J; Paris, M. W ...
Chinese physics C,
12/2009, Letnik:
33, Številka:
12
Journal Article
Recenzirano
Odprti dostop
We discuss the analysis of data from πN elastic scattering and single pion photo- and electroproduction. The main focus is a study of low-lying non-strange baryon resonances. Here we concentrate on ...some difficulties associated with resonance identification, in particular the Roper and higher P11 states.
Although estrogen and the enzymes responsible for its metabolism have been detected within the lung, the ability of this tissue to metabolize estrogen has not been demonstrated previously. The goal ...of this study was to characterize the profile of estrogen metabolites within the murine lung and to determine the effect of tobacco smoke exposure on metabolite levels. Use of liquid chromatography-tandem mass spectrometry led to the detection of three estrogens (E1, E2 and E3) and five estrogen metabolites (2-OHE1, 4-OHE1, 4-OHE2, 2-OMeE1 and 2-OMeE2) within the perfused lung, with 4-OHE1 being the most abundant species. Levels of 4-OHEs, carcinogenic derivatives produced primarily by cytochrome P450 1B1 (Cyp1b1), were 2-fold higher in females than males. Deletion of Cyp1b1 in females led to a dramatic reduction (21-fold) in 4-OHEs, whereas levels of 2-OHE1 and the putative protective estrogen metabolite 2-OMeE2 were increased (2.4- and 5.0-fold, respectively) (P = 0.01). Similar quantitative differences in estrogen metabolite levels were observed between Cyp1b1 null and wild-type males. Exposure of female mice to tobacco smoke for 8 weeks (2h per day, 5 days per week) increased the levels of 4-OHE1 (4-fold) and 2-OHE2 (2-fold) within the lung while reducing the total concentration of 2-OMeEs to 70% of those of unexposed controls. These data suggest that tobacco smoke accelerates the production of 4-OHEs within the lung; carcinogenic metabolites that could potentially contribute to lung tumor development. Thus, inhibition of CYP1B1 may represent a promising strategy for the prevention and treatment of lung cancer.
Electromagnetic resonance properties are uniquely defined at the pole and do not depend on the separation of the resonance from background or the decay channel. Photon-nucleon branching ratios are ...nowadays often quoted at the pole, and we generalize the considerations to the case of virtual photons. In this paper, we derive and compare relations for nucleon to baryon transition form factors both for the Breit-Wigner and the pole positions. Using the MAID2007 and SAID SM08 partial wave analyses of pion electroproduction data, we compare the $G_M$, $G_E$, and $G_C$ form factors for the $\Delta(1232)$ resonance excitation at the Breit-Wigner resonance and pole positions up to $Q^2=5$ GeV$^2$. We also explore the $E/M$ and $S/M$ ratios as functions of $Q^2$. Finally, for pole and residue extraction, we apply the Laurent + Pietarinen method.
PDF
