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Title: Observation and properties of X(3872) at D0

Abstract

Since the X(3872) was discovered by the Belle Collaboration in August 2003, it's interpretation through the Standard Model has been difficult. Many possible interpretations have been proposed due to its close proximity to the D$$\bar{D}$$* mass threshold, ranging from a new state in the charmonium spectrum to a 4-quark state to a weakly bound meson molecule. Probing the X(3872) is also made difficult due to low statistical samples at e +e - colliders and large combinatoric backgrounds at hadron colliders such as the Tevatron. This paper presented the results of probes of this state performed at the D0 detector.

Authors:
 [1]
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  1. Oklahoma City Univ., OK (United States)
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
902537
Report Number(s):
FERMILAB-THESIS-2007-03
TRN: US200721%%374
DOE Contract Number:
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CHARMONIUM; FERMILAB TEVATRON; HADRONS; MESONS; PROBES; STANDARD MODEL; Experiment-HEP

Citation Formats

Hall, Isaac Nathaniel. Observation and properties of X(3872) at D0. United States: N. p., 2007. Web. doi:10.2172/902537.
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Hall, Isaac Nathaniel. Observation and properties of X(3872) at D0. United States. doi:10.2172/902537.
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Hall, Isaac Nathaniel. Mon . "Observation and properties of X(3872) at D0". United States. doi:10.2172/902537. https://www.osti.gov/servlets/purl/902537.
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@article{osti_902537,
title = {Observation and properties of X(3872) at D0},
author = {Hall, Isaac Nathaniel},
abstractNote = {Since the X(3872) was discovered by the Belle Collaboration in August 2003, it's interpretation through the Standard Model has been difficult. Many possible interpretations have been proposed due to its close proximity to the D$\bar{D}$* mass threshold, ranging from a new state in the charmonium spectrum to a 4-quark state to a weakly bound meson molecule. Probing the X(3872) is also made difficult due to low statistical samples at e+e- colliders and large combinatoric backgrounds at hadron colliders such as the Tevatron. This paper presented the results of probes of this state performed at the D0 detector.},
doi = {10.2172/902537},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
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Thesis/Dissertation:
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DOI:  10.2172/902537
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  • ;
    This dissertation presents two analyses performed on data collected with the BABAR detector at the SLAC PEP-II e{sup +}e{sup -} asymmetric-energy B Factory. First, a Dalitz analysis is shown that performs the first measurement of CP violation parameters in the decay B{sup -} {yields} D{sub {pi}{sup +}{pi}{sup -}{pi}{sup 0}}K{sup -} using the decay rate asymmetry and D{sup 0} - {bar D}{sup 0} interference. The results can be used to further constrain the value of the CKM angle {gamma}. The second analysis studies the properties of the X(3872) in neutral and charged B {yields} J/{psi}{pi}{sup +}{pi}{sup -}K decays. Measurements of themore » branching ratio and mass are presented as well as the search for additional resonances at higher masses.« less

  • 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 electromagneticmore » force), W ± and Z 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.« less

  • This thesis studied properties of the charmonium-like X(3872) state, which is an exotic matter candidate. The measurements are performed using a data sample collected with the CDF experiment.

  • The author presents a measurement of the dipion mass spectrum in the decay X(3872) → J/Ψπ + π - using a 360 pb -1 sample of pmore » $$\bar{p}$$ collisions at √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 Ψ(2S) → J/Ψπ + π - 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) → J/Ψρ 0. They find that the measured spectrum is compatible with 3S 1 charmonium decaying to J/Ψπ + π - and with the X(3872) → J/Ψρ 0 hypothesis. There is, however, no 3S 1 charmonium state available for assignment to the X(3872). The multipole expansion calculations for 1P 1 and 3D J states are in clear disagreement with the X(3872) data. For the Ψ(2S) the data agrees well with previously published results and to multipole expansion calculations for 3S 1 charmonium. Other, non-charmonium, models for the X(3872) are described too. They conclude that since the dipion mass spectrum for X(3872) is compatible with J/Ψρ 0 hypothesis, the X(3872) should be C-positive. This conclusion is supported by recent results from Belle Collaboration which observed X(3872) → J/Ψγ decay. They argue that if X(3872) is a charmonium, then it should be either 1D 2± or 2 3P 1++ state, decaying into J/Ψπ + π - in violation of isospin conservation. A non-charmonium assignment, such as D$$\bar{D}$$* molecule, is also quite possible.« less