Cdf Grid Computing And The Decay X 3872 J Psi Pi Pi With J Psi E E


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CDF Grid Computing and the Decay X(3872) ---] J/psi Pi+ Pi- with J/psi ---] E+ E-


CDF Grid Computing and the Decay X(3872) ---] J/psi Pi+ Pi- with J/psi ---] E+ E-

Author: Ulrich Kerzel

language: en

Publisher:

Release Date: 2005


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The main aim of physics research is to obtain a consistent description of nature leading to a detailed understanding of the phenomena observed in experiments. The field of particle physics focuses on the discovery and understanding of the fundamental particles and the forces by which they interact with each other. Using methods from group theory, the present knowledge can be mathematically described by the so-called ''Standard Model'', which interprets the fundamental particles (quarks and leptons) as quantum-mechanical fields interacting via the electromagnetic, weak and strong force. These interactions are mediated via gauge particles such as the photon (for the electromagnetic force), W{sup {+-}} and Z{sup 0} (for the weak force) and gluons (for the strong force). Gravitation is not yet included in this description as it presently cannot be formulated in a way to be incorporated in the Standard Model. However, the gravitational force is negligibly small on microscopic levels. The validity of this mathematical approach is tested experimentally by accelerating particles such as electrons and protons, as well as their antiparticles, to high energies and observing the reactions as these particles collide using sophisticated detectors. Due to the high energy of the particles involved, these detectors need to be as big as a small house to allow for precision measurements. Comparing the predictions from theory with the analyzed reactions observed in these collisions, the Standard Model has been established as a well-founded theory. Precision measurements from the four experiments (Aleph, Delphi, Opal, L3) the Large Electron Positron collider (LEP), operated at CERN during the years 1989-2000, allow the determination of the Standard Model parameters with enormous accuracy.

CDF Grid Computing and the Decay X(3872) {u2192} J/?i ?+ ?- with J/? {u2192} E+ E-.


CDF Grid Computing and the Decay X(3872) {u2192} J/?i ?+ ?- with J/? {u2192} E+ E-.

Author:

language: en

Publisher:

Release Date: 2005


DOWNLOAD





The main aim of physics research is to obtain a consistent description of nature leading to a detailed understanding of the phenomena observed in experiments. The field of particle physics focuses on the discovery and understanding of the fundamental particles and the forces by which they interact with each other. Using methods from group theory, the present knowledge can be mathematically described by the so-called ''Standard Model'', which interprets the fundamental particles (quarks and leptons) as quantum-mechanical fields interacting via the electromagnetic, weak and strong force. These interactions are mediated via gauge particles such as the photon (for the electromagnetic force), W± and Z0 (for the weak force) and gluons (for the strong force). Gravitation is not yet included in this description as it presently cannot be formulated in a way to be incorporated in the Standard Model. However, the gravitational force is negligibly small on microscopic levels. The validity of this mathematical approach is tested experimentally by accelerating particles such as electrons and protons, as well as their antiparticles, to high energies and observing the reactions as these particles collide using sophisticated detectors. Due to the high energy of the particles involved, these detectors need to be as big as a small house to allow for precision measurements. Comparing the predictions from theory with the analyzed reactions observed in these collisions, the Standard Model has been established as a well-founded theory. Precision measurements from the four experiments (Aleph, Delphi, Opal, L3) the Large Electron Positron collider (LEP), operated at CERN during the years 1989-2000, allow the determination of the Standard Model parameters with enormous accuracy.

Measurement of the Dipion Mass Spectrum in the Decay X(3872) -] J/psi Pi+ Pi- at the CDF II Experiment


Measurement of the Dipion Mass Spectrum in the Decay X(3872) -] J/psi Pi+ Pi- at the CDF II Experiment

Author:

language: en

Publisher:

Release Date: 2005


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The authors present a measurement of the dipion mass spectrum in the decay X(3872) [yields] J/[psi][pi][sup +][pi][sup -] using a 360 pb[sup -1] sample of p[bar p] collisions at [radical]s = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron Collider. As a benchmark, they also extract the dipion mass distribution for [psi](2S) [yields] J/[psi][pi][sup +][pi][sup -] decay. The X(3872) dipion mass spectrum is compared to QCD multipole expansion predictions for various charmonium states, as well as to the hypothesis X(3872) [yields] J/[psi]p[sup 0]. They find that the measured spectrum is compatible with [sup 3]S[sub 1] charmonium decaying to J/[psi][pi][sup +][pi][sup -] and with the X(3872) [yields] J/[psi]p[sup 0] hypothesis. There is, however, no [sup 3]S[sub 1] charmonium state available for assignment to the X(3872). The multipole expansion calculations for [sup 1]P[sub 1] and [sup 3]D[sub J] states are in clear disagreement with the X(3872) data. For the [psi](2S) the data agrees well with previously published results and to multipole expansion calculations for [sup 3]S[sub 1] charmonium. Other, non-charmonium, models for the X(3872) are described too. The authors conclude that since the dipion mass spectrum for X(3872) is compatible with J/[psi]p[sup 0] hypothesis, the X(3872) should be C-positive. This conclusion is supported by recent results from Belle Collaboration which observed X(3872) [yields] J/[psi][gamma] decay. They argue that if X(3872) is a charmonium, then it should be either 1[sup 1]D[sub 2-+] or 2[sup 3]P[sub 1++] state, decaying into J/[psi][pi][sup +][pi][sup -] in violation of isospin conservation. A non-charmonium assignment, such as D[bar D]* molecule, is also quite possible.