Release_Note

In this document, the production of Xibar+Xi- pairs is simulated in the pbarp -> Xibar+Xi- reaction channel at beam momenta of p_beam=7.0 GeV/c and p_beam=4.6 GeV/c. The first beam momentum is chosen at the energy corresponding to the formation of the X(3872), where a large data taking campaign is foreseen when PANDA is operational. The second beam momentum is chosen around 100 MeV/c2 above the production threshold of Xibar(1820)+Xi- + c.c. The feasibility to measure polarisations and spin correlations in the reaction channel is studied for the sequential process Xi- -> Lambda pi-, Lambda -> p pi- + c.c.

The PANDA experiment is one of the main pillars of the FAIR facility, currently under construction in Darmstadt, Germany. The PANDA will be a fixed target experiment designed for the study of non-perturbative phenomena of the strong interaction. Strange hyperon production is governed by the mass of the strange quark, m(s) ∼ 100 MeV, which corresponds to the confinement domain. Thus, hyperons are suitable probes in this energy region. This work is a simulation study focused on the feasibility of studying the production of the Sigmabar and Lambda hyperons in the pbar p ->Sigmabar Lambda reaction with the PANDA detector. A 10^4 events sample simulated at pbeam = 1.771 GeV/c is used to perform a single-tag (inclusive) and a double-tag (exclusive) event selection. From the former, it is concluded that the single-tag method does not provide with the clean signal required for spin observables extraction. In contrast, exclusive event selection provides with a signal reasonably clean from combinatorial background and completely clean from generic hadronic background events. A signal ( Sigmabar Lambda) reconstruction efficiency of e = 5.3 ± 0.2 % is obtained for exclusive event selection. The corresponding signal to background ratio is S/B Total ∼ 6 and the significance value
is ∼ 21.
In addition, an exclusive event selection is performed on a 10^4 events sample simulated at pbeam = 6 GeV/c. Almost all the generic hadronic background events are removed by the applied selection criteria. At this beam momentum, the obtained signal efficiency is e = 6.1 ± 0.3%, the signal to total background ratio is S/B Total ∼ 4 and the significance is ∼ 22. Both efficiencies are smaller compared to a previous simulation study on this channel, but are large enough to enable a study of the exclusive production of the pbar p -> Sigmabar Lambda reaction at PANDA. The difference between the results of this work and the previous work is attributed to the more realistic implementation of the signal production mechanism, as well as the detector and reconstruction algorithms.

The energy scale of hyperon production in pbarp -> YbarY reactions is given by the strange quark mass, which is close to the QCD cut-off region. In this energy scale, it is not clear whether quarks and gluons or hadrons act as the relevant degrees of freedom. Studying spin observables in these reactions could give new insight in QCD in the intermediate energy region.

In this feasibility study, the measurement of polarisation and spin correlation, the two accessible spin observables in PANDA, are studied. Expected observed production rates of antihyperon hyperon pairs are also presented. This study is an extension of previous similar work performed with a different software package.

This release note reports about feasibility studies for the measurement of time-like proton electromagnetic form factors (FF's) using reactions of the type $\bar{p} p \rightarrow \mu^{+} \mu^{-}$ at the PANDA experiment at FAIR. Electromagnetic form factors are fundamental quantities which parameterize the electric and magnetic structure of hadrons. In the time-like region, the FF's can be accessed through reactions of the type $p\bar{p}\rightarrow l^{+} l^{-}$, where l = e, $\mu$, under the assumption of one photon exchange. It will be the first time that muon pairs in the final state will be used for the individual measurement of the TL em FF's of the proton. One advantage of using this channel is that radiative corrections due to final state radiation are suppressed by the heavy mass of the muon. Measuring $\bar{p} p \rightarrow \mu^{+} \mu^{-}$ will also serve as a consistency check of the TL em FF data from $\bar{p} p \rightarrow e^{+} e^{-}$. In frame of the PANDARoot software, which encompasses full detector simulation and event reconstruction, the statistical precision at which the proton FF's will be determined at PANDA is estimated for the signal reaction $p \bar{p} \rightarrow \mu^{+} \mu^{-}$ at different antiproton beam momenta. The signal identification and the suppression of the main background process ($p\bar{p} \rightarrow \pi^{+} \pi^{-}$) are studied. In addition, the expected statistical precision of the effective TL proton FF is presented at different beam momenta. Possible systematic error sources are considered for the estimation of the total uncertainties.

A kind of dummy RN to have a reference for released material upload of detector specific drawings.

The figures presented in this release note describe the arguments for the choice for the primary target material and several potential physics topics in the field of hypernuclei and hyperatom studies for $\panda$.
We intend to publish these figures and the tables in a regular paper to be submitted to Nuclear Physics A.

Although being the first of the new charmonium-like states discovered since 2003 \cite{BelleX3872}, the $X(3872)$ is still one of the most puzzling ones concerning the properties. Since the mass is indistinguishably close to the sum $m(D^0) + m(\bar{D}^{\ast 0})$, it is unclear whether it lays above or beneath the $DD^{\ast}$ threshold. Furthermore, the natural width is very small and basically unknown up to a rather rough upper limit of $\Gamma_X < 1.2$ MeV \cite{PDG15}. Due to these extra-ordinary properties, this state is frequently suggested to be an exotic hadron, possibly featuring a different and more complex internal structure than a simple conventional mesonic $q\bar{q}$ state. In particular, several theoretical models (e.g. \cite{BraatenLS,HanhartLS,KalashLS}) relate not only the mass $m_X$ and the Breit-Wigner-like width $\Gamma_X$ to the internal structure, but explicitly also the line-shape of the resonance. This offers another experimental handle to identify the nature of the $X(3872)$.

In this work, we study the expected sensitivity of energy scans of narrow resonances performed with the HESR in combination with the PANDA detector at FAIR. The goal is to access experimentally the aforementioned properties for different hypothetical experimental and physical scenarios of the $X(3872)$. It represents an update and extension of an earlier simulation study of that state carried out in 2011 based on a different software revision \cite{Galuska2012}. Furthermore, this exemplary study serves as a proof of principle for high precision spectroscopy using the energy scan method with the PANDA experiment in general.