The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the \PANDA detector is discussed. Detailed simulations on signal efficiency for the ...annihilation of $\bar p +p $ into a lepton pair as well as for the most important background channels have been performed. It is shown that precision measurements of the differential cross section of the reaction $\bar p +p \to e^++ e^-$ can be obtained in a wide angular and kinematical range. The individual determination of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of $q^2\simeq 14$ (GeV/c)$^2$. The total $\bar p +p\to e^++e^-$ cross section will be measured up to $q^2\simeq 28$ (GeV/c)$^2$. The results obtained from simulated events are compared to the existing data. Sensitivity to the two photons exchange mechanism is also investigated.
The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the
ANDA detector is discussed. Detailed simulations on signal efficiency for the ...annihilation of
+
p
into a lepton pair as well as for the most important background channels have been performed. It is shown that precise measurements of the differential cross-section of the reaction
+
p
e
-
+
e
+
can be obtained in a wide kinematical range. The determination of the ratio
R
of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of
q
2
≃ 14 (GeV/
c
)^2 with absolute precision from 0.01 to 0.5 (for
R
∼ 1 . The total
+
p
e
-
+
e
+
cross-section will be measured up to
q
2
≃ 28 (GeV/
c
)^2. The results obtained from simulated events are compared to the existing data. Sensitivity to the two-photon exchange mechanism is also investigated.
The Beijing Spectrometer (BESIII) collaboration uses \(e^+e^-\) collisions in the tau-charm energy region to study a broad spectrum of topics. These include studies of light mesons and light baryons, ...studies of charmonium, including exotic mesons and baryons containing charmonium, studies of charmed mesons and baryons, studies of QCD and tau physics, as well as searches for new physics. The following is a Snowmass white paper that outlines the BESIII accomplishments and potential in each of these areas.
Using \(e^{+}e^{-}\) collision data samples with center-of-mass energies ranging from 2.000 to 2.644 GeV, collected by the BESIII detector at the BEPCII collider, and with a total integrated ...luminosity of 300 pb^{-1}, a partial-wave analysis is performed for the process \(e^{+}e^{-} \to K^{+}K^{-}\pi^{0}\pi^{0}\). The total Born cross sections for the process \(e^{+}e^{-} \to K^{+}K^{-}\pi^{0}\pi^{0}\), as well as the Born cross sections f or the subprocesses \(e^{+}e^{-} \to \phi \pi^{0}\pi^{0}\), \(K^{+}(1460)K^{-}\), \(K^{+}_{1}(1400)K^{-}\), \(K^{+}_{1}(1270)K^{-}\) and \(K^{*+}(892)K^{*-}(892)\), are measured versus the center-of-mass energy. The corresponding results for \(e^{+}e^{-} \to K^{+}K^{-}\pi^{0}\pi^{0}\) and \(\phi \pi^{0}\pi^{0}\) are consistent with those of BaBar and have much improved precision.By analyzing the cross sections for the four subprocesses, \(K^{+}(1460)K^{-}\), \(K^{+}_{1}(1400)K^{-}\), \(K^{+ }_{1}(1270)K^{-}\) and \(K^{*+}K^{*-}\), a structure with mass \(M\) = (2126.5 \(\pm\) 16.8 \(\pm\) 12.4)~MeV/c^{2} and width \(\Gamma\) = (106.9 \(\pm\) 32.1 \(\pm\) 28.1)~MeV is observed with an overall statistical significance of 6.3 \(\sigma\), although with very limited significance in the subprocesses \(e^{+}e^{-} \to K^{+}_{1}(1270)K^{-}\) and \(K^{*+}(892)K^{*-}(892)\). The resonant parameters of the observed structure suggest it can be identified with the \(\phi(2170)\), thus the results provide valuable input to the internal nature of the \(\phi(2170)\).
The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the \PANDA detector is discussed. Detailed simulations on signal efficiency for the ...annihilation of \(\bar p +p \) into a lepton pair as well as for the most important background channels have been performed. It is shown that precision measurements of the differential cross section of the reaction \(\bar p +p \to e^++ e^-\) can be obtained in a wide angular and kinematical range. The individual determination of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of \(q^2\simeq 14\) (GeV/c)\(^2\). The total \(\bar p +p\to e^++e^-\) cross section will be measured up to \(q^2\simeq 28\) (GeV/c)\(^2\). The results obtained from simulated events are compared to the existing data. Sensitivity to the two photons exchange mechanism is also investigated.
Avec le présent livre paraît maintenant le volume 2 de la collection « Studia Habsburgica ». La publication a été retardée, car tous les auteurs n’ont pas eu et n’ont toujours pas ou peu accès aux ...sources et à la littérature depuis février-mars de l’année 2020. Au moment où nous rédigeons cette introduction en janvier 2021, les salles de lecture sont encore ou à nouveau fermées et les conditions de travail restent difficiles. Je suis d’autant plus reconnaissant aux auteurs, mais aussi aux di...
Resonances in QCD Lutz, Matthias F.M.; Lange, Jens Sören; Pennington, Michael ...
Nuclear physics. A,
04/2016, Letnik:
948, Številka:
C
Journal Article
Recenzirano
Odprti dostop
We report on the EMMI Rapid Reaction Task Force meeting ‘Resonances in QCD’, which took place at GSI October 12–14, 2015. A group of 26 people met to discuss the physics of resonances in QCD. The aim ...of the meeting was defined by the following three key questions:•What is needed to understand the physics of resonances in QCD?•Where does QCD lead us to expect resonances with exotic quantum numbers?•What experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with up, down and strange quark content were considered. For heavy–light and heavy–heavy meson systems, those with charm quarks were the focus.
This document summarizes the discussions by the participants, which in turn led to the coherent conclusions we present here.
« Rome n’est plus dans Rome, elle est toute où je suis », peut-on lire dans une tragédie de Corneille. Inversant le proverbe qui dit que tous les chemins mènent à Rome, cet ouvrage va révéler combien ...les voies partant de Rome conduisent vers d’insoupçonnables ailleurs. Du xvie au xviiie siècle, de nombreuses villes se sont réapproprié le mythe de Rome, dépositaire d’un idéal politique impérial et républicain, et capitale d’une religion à vocation universelle. Ces réappropriations, qui ne fonctionnent jamais par simple mimétisme vis-à-vis des réalités romaines, sont un véritable objet d’histoire politique et culturelle. Du Moscou des Romanov, à la Virginie de Jefferson, en passant par le Saint-Empire, l’Espagne ou la France, ce livre est un appel au voyage conduisant de Rome au reste de l’Europe et du monde. Ouvrant la voie à une histoire mondiale de Rome, qui reste à écrire, il offre divers modèles d’interprétation des liens qui se tissent entre les villes, dans la rugosité de leurs édifices comme la plasticité de leurs imaginaires.
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