Observation and Properties of the <i>X(3872)</i> at CDF

Observation and Properties of the X(3872) at CDF

Fall 2005: Fit dipion mass spectrum with Relativistic Breit-Wigner with Blatt-Weiskopf form factors. Both S- and P-wave decays can describe data.
Summer 2005: Observe X(3872) -> J/ψππ in challenging J/&psi ->e+e- mode
Spring 2005: Dipion mass spectrum for X(3872) -> J/ψππ decay is obtained. Simple Breit-Wigner fit of X-> J/ψ&rho Preferred.
Summer 2004: The Production Fractions of the X-sample from b-hadron decays via the apparent "X-lifetime."
Dec 4, 2003: PRL submitted with final mass measurement [PRL 93, 072001 (2004)].
Sept 2003: CDF provided the first confirmation of Belle's discovery of a narrow state, the X(3872), decaying into J/ψππ at the Fermilab Quarkonium Workshop on Sept 20.

Measurement of the Dipion Mass Spectrum in X(3872) -> J/ψ π π Decay [360 pb^-1]:

The Submission to PRL [hep-ex/0512074]
Below are the eps versions of figures and eps and tex files with tables meant for downloads, and some brief descriptions.

A sample of 360 pb-1 is used in this analysis. The resulting J/ψππ mass distribution is shown in:
- J/ψπ&pi Mass-- Default (before and after cut M(ππ) > 500 MeV/c²)
- J/ψπ&pi Mass-- Alternate (with additional "inverse" cut M(ππ) < 500 MeV/c²)
The sample is divided into M(PiPi) "slices" and the J/ψππ mass distribution is fit for X(3872) signal.

Examples of X(3872) fits of the J/ψππ mass distribution for selected M(ππ) slices

Yields are corrected for detector and selection efficiencies:

Relative detector efficiency corrections

The ψ(2S) serves as a good control sample:

ψ(2S) Dipion mass spectrum -- Default (with only 3S1 QCD multipole Expansion fit) [PRL Version]
ψ(2S) Dipion mass spectrum -- Alternate 1 (fit with Multipole Expansion and older model of Brown & Cahn for contrast)
ψ(2S) Dipion mass spectrum -- Alternate 2 (fit with various models)
Table of Fit results for ψ(2S) + tex source

Efficiency corrected DiPion Mass Spectrum for X(3872) fit to various models:
-- QCD multipole expansion model for C-odd charmonia
-- Relativistic Briet-Wigner model of J/&psi&rho for C-even states (charmonia or not)
- Default &pi&pi Mass Spectrum (fit with Multipole Expansion for C-odd charmonia and J/&psi&rho hypotheses)
- Simplified version - (fit with Multipole Expansion only)
- Simplified version - (fit with J/&psi&rho only)
Introduce effects of &rho-&omega Interference into J/&psi&rho Fit Model:
- Blow-Up of &pi&pi Spectrum fit by J/&psi&rho with &rho-&omega interference (PRL Version with fit probability inset)
- Simplified version - (NO inset)
- Separate plots of L=0 and L=1 interference fits cccc
- Study the sensitivity of the L=0 fits on various model parameters:
  - Vary Interference Phase (&phi) and Blatt-Weisskopf Radius of the &rho (R_&rho)
  - Vary Interference Phase (&phi) and &omega-to-&rho branching ratio (R_3/2)
- Study the sensitivity of the L=1 fits on various model parameters:

Observation of X(3872) -> J/ψππ in J/&psi ->e+e- Mode

Study of the Production Fractions of the X(3872) [220 pb^-1]:

A public write-up: CDF7159
Below are the eps versions of figures meant for downloads.

Figure 1 - Full J/ψππ Mass Distribution
Figure 2:

Top - ψ(2S) mass distribution
Bottom - ψ(2S) lifetime distribution

Figure 3 - ψ(2S) lifetime distribution around 2.5σ of ψ(2S)
Figure 4 - Sideband-subtracted ψ(2S) lifetime distribution
Figure 5:

Top - X(3872) mass distribution
Bottom - X(3872) lifetime distribution

Figure 6 - X(3872) lifetime distribution around 2.5σ of X(3872)
Figure 7 - Sideband-subtracted X(3872) lifetime distribution
Figure 8:

Top - ψ(2S) positive lifetime tails
Bottom - X(3872) positive lifetime tails

Observation and Mass Measurement of the X(3872) [220 pb^-1]:

Paper Published in Phys. Rev. Lett. 93, 072001 (2004)
Below are the eps versions of figures meant for downloads.

Figure 1:

Figure 2:

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