Search results for "Partial"

Study of J/ψ and ψ(3686) decays to π+π−η′

2017

Using the data samples of 1.31 x 10(9) J/psi events and 4.48 x 10(8) psi(3686) events collected with the BESIII detector, partial wave analyses on the decays J/psi and psi(3686) pthornp -> pi(+)pi(-)eta' are performed with a relativistic covariant tensor amplitude approach. The dominant contribution is found to be J/psi and psi(3686) decays to rho eta' In the J/psi decay, the branching fraction B(J/psi -> rho eta') is determined to be (7.90 +/- 0.19(stat) +/- 0.49(sys)) x 10(-5). Two solutions are found in the psi(3686) decay, and the corresponding branching fraction B(psi(3686) -> rho eta') is (1.02 +/- 0.11(stat) +/- 0.24(sys)) x 10(-5) for the case of destructive interference, and (5.69 …

Electroweak effects in intermediate energy physics

2008

Measurement of theH1(γ⃗, p⃗)π0Reaction Using a Novel Nucleon Spin Polarimeter

2014

We report the first large-acceptance measurement of polarization transfer from a polarized photon beam to a recoiling nucleon. The measurement pioneers a novel polarimetry technique, which can be applied to many other nuclear and hadron physics experiments. The commissioning reaction of $^{1}H(\mathrm{\ensuremath{\gamma}P\vec},\text{ }\mathrm{pP\vec}){\ensuremath{\pi}}^{0}$ in the range $0.4l{E}_{\ensuremath{\gamma}}l1.4\text{ }\text{ }\mathrm{GeV}$ validates the technique and provides essential new data to constrain the excitation spectrum of the nucleon.

Measurement of theI=1/2Kπ S-wave amplitude from Dalitz plot analyses ofηc→KK¯πin two-photon interactions

2016

We study the processes γγ→K^0_SK^±π^∓ and γγ→K^+K^−π^0 using a data sample of 519  fb^(−1) recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e+e− collider at center-of-mass energies at and near the Υ(nS) (n=2, 3, 4) resonances. We observe ηc decays to both final states and perform Dalitz plot analyses using a model-independent partial wave analysis technique. This allows a model-independent measurement of the mass-dependence of the I=1/2 Kπ S-wave amplitude and phase. A comparison between the present measurement and those from previous experiments indicates similar behavior for the phase up to a mass of 1.5  GeV/c^2. In contrast, the amplitudes show very marked…

Regge phenomenology of theN*andΔ*poles

2019

We use Regge phenomenology to study the structure of the poles of the ${N}^{*}$ and ${\mathrm{\ensuremath{\Delta}}}^{*}$ spectrum. We employ the available pole extractions from partial wave analysis of meson scattering and photoproduction data. We assess the importance of the imaginary part of the poles (widths) to obtain a consistent determination of the parameters of the Regge trajectory. We compare the several pole extractions and show how Regge phenomenology can be used to gain insight into the internal structure of baryons. We find that the majority of the states in the parent Regge trajectories are compatible with a mostly compact three-quark state picture.

Measurement of the transverse target and beam-target asymmetries in η meson photoproduction at MAMI

2014

We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the $\vec \gamma \vec p\to\eta p$ reaction up to a center-of-mass energy of W=1.9 GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. All existing model predictions fail to reproduce the new data indicating a significant impact on our understanding of the underlying dynamics of $\eta$ meson photoproduction. The peculiar nodal structure observed in existing T data close to threshold is not confirmed.

Single-energy partial wave analysis for pion photoproduction with fixed-t analyticity

2021

Experimental data for pion photoproduction including differential cross sections and various polarization observables from four reaction channels, $\gamma p \to \pi^0 p$, $\gamma p \to \pi^+n$, $\gamma n \to \pi^- p$ and $\gamma n \to \pi^0 n$ from threshold up to $W=2.2$ GeV have been used in order to perform a single-energy partial wave analysis with minimal model dependence by imposing constraints from unitarity and fixed-$t$ analyticity in an iterative procedure. Reaction models were only used as starting point in the very first iteration. We demonstrate that with this procedure partial wave amplitudes can be obtained which show only a minimal dependence on the initial model assumptions…

Strong Enhancement ofɛ′/ɛthrough Final State Interactions

2000

We quantify the important effect of strong final state interactions in the weak $K\ensuremath{\rightarrow}2\ensuremath{\pi}$ amplitudes, using the measured $\ensuremath{\pi}\ensuremath{-}\ensuremath{\pi}$ phase shifts with $J\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$ and $I\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0,2$. The final rescattering of the two pions provides a strong enhancement of the $\ensuremath{\Delta}I\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1/2$ amplitude, which so far has been neglected in the theoretical predictions of ${\ensuremath{\varepsilon}}^{\ensuremath{'}}/\ensuremath{\varepsilon}$. This correction increases the standard model predictio…

A Temperature Dependent Non-Linear Inductor Model for a DC/DC Boost Converter

2018

This paper is focused on the use of non-linear inductors in DC/DC switching converters, as well as their behaviour due to changes in current and temperature. The model of an inductor is set up on the basis of experimental data, which are automatically acquired by a virtual instrument; from those data, a polynomial curve describing the inductance variations is obtained. The analysis of the converter, performed by including the proposed model, is validated by experimental tests.

Observation of pseudoscalar and tensor resonances in J /ψ →γφφ

2016

Based on a sample of (1310.6 +/- 10.5) x 10(6) J/psi events collected with the BESIII detector operating at the BEPCII storage ring, a partial wave analysis of the decay J/psi -> gamma phi phi is performed in order to study the intermediate states. Results of the partial wave analysis show that the structures are predominantly 0(-+) states. The existence of the eta(2225) is confirmed, and its resonance parameters are measured. Two additional pseudoscalar states, the eta(2100) with a mass of 2050(-24-26)(+30+75) MeV/c(2) and a width of 250(-30-164)(+36+181) MeV/c(2) and the X(2500) with a mass of 2470(-19-23)(+15+101) MeV/c(2) and a width of 230(-35-33)(+64+56) MeV/c(2), are observed. In add…