We present a measurement of the dipion mass spectrum in the decay X(3872) [right arrow] J/ [psi] [pi]+ [pi]− using a 360 pb-1 sample of pp collisions at av [square root]s = 1.96 TeV collected with the CDF II detector at the Fermnilab Tevatron Collider. As a benchmark, we also extract the dipion mass distribution for [psi] (2s) [right arrow] J/ [psi] [pi]+ [pi]− decay. The X(3872) dipion mass spectrum is compared to QCD multipole expansion predictions for various charmonium states, as well as to the hypothesis [right arrow] J/ [psi] po. We find that the measured spectrum is compatible with 3S1 charmonium decaying to J/ [psi] [pi]+ [pi]− - and with the X(3872) - J/po hypothesis. There is, however, no 3S1 charmonium state available for assignment to the X(3872). The multipole expansion calculations for 1P1 and 3DJ 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 3S1 charmonium. Other, non-charmonium, models for the X(3872) are described too. We conclude that since the dipion mass spectrum for X(3872) is compatible with J/pO hypothesis, the X(3872) should be C-positive. This conclusion is supported by recent results from Belle Collaboration which observed X(3872) -+ J/7y decay. We argue that if X(3872) is a charmonium, then it should be either ... state, decaying into J/ [psi] [pi]+ [pi]− in violation of isospin conservation. A non-charmonium assignment, such as DD* molecule, is also quite possible.

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.

The author presents a measurement of the dipion mass spectrum in the decay X(3872) → J/[Psi][pi]+ [pi]- using a 360 pb-1 sample of p$\bar{p}$ 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 [Psi](2S) → J/[Psi][pi]+ [pi]- 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/[Psi][rho]0. They find that the measured spectrum is compatible with 3S1 charmonium decaying to J/[Psi][pi]+ [pi]- and with the X(3872) → J/[Psi][rho]0 hypothesis. There is, however, no 3S1 charmonium state available for assignment to the X(3872). The multipole expansion calculations for 1P1 and 3DJ 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 3S1 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/[Psi][rho]0 hypothesis, the X(3872) should be C-positive. This conclusion is supported by recent results from Belle Collaboration which observed X(3872) → J/[Psi][gamma] decay. They argue that if X(3872) is a charmonium, then it should be either 1D2± or 23P1++ state, decaying into J/[Psi][pi]+ [pi]- in violation of isospin conservation. A non-charmonium assignment, such as D$\bar{D}$* molecule, is also quite possible.

The authors measure the dipion mass spectrum in X(3872) → J/???− decays using 360 pb−1 of {bar p}p collisions at √s = 1.96 TeV collected with the CDF II detector. The spectrum is fit with predictions for odd C-parity (3S1, 1P1, and 3D{sub J}) charmonia decaying to J/??+?−, as well as event C-parity states in which the pions are from?° decay. The latter case also encompasses exotic interpretations, such as a D°{bar D}*° molecule. Only the 3S1 and J/?? hypotheses are compatible with the data. Since 3S1 is untenable on other grounds, decay via J/?? is favored, which implies C = +1 for the X(3872). Models for different J/?-? angular momenta L are considered. Flexibility in the models, especially the introduction of?-? interference, enable good descriptions of the data for both L = 0 and 1.

The author presents a measurement of the dipion mass spectrum in the decay X(3872) → J/??+ ?- using a 360 pb-1 sample of p$ar{p}$ 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 ?(2S) → J/??+ ?- 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/??0. They find that the measured spectrum is compatible with 3S1 charmonium decaying to J/??+ ?- and with the X(3872) → J/??0 hypothesis. There is, however, no 3S1 charmonium state available for assignment to the X(3872). The multipole expansion calculations for 1P1 and 3DJ states are in clear disagreement with the X(3872) data. For the ?(2S) the data agrees well with previously published results and to multipole expansion calculations for 3S1 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/??0 hypothesis, the X(3872) should be C-positive. This conclusion is supported by recent results from Belle Collaboration which observed X(3872) → J/?? decay. They argue that if X(3872) is a charmonium, then it should be either 1D2± or 23P1++ state, decaying into J/??+ ?- in violation of isospin conservation. A non-charmonium assignment, such as D$ar{D}$* molecule, is also quite possible.

The author reports results on the X(3872) from the Tevatron. Mass and other properties have been studied, with a focus on new results on the dipion mass spectrum in X {yields} J/{psi}{pi}{sup +}{pi}{sup -} decays. Dipions favor interpreting the decay as J/{psi}{rho}, implying even C-parity for the X. Modeling uncertainties do not allow distinguishing between S- and P-wave decays of the J/{psi}-{rho} mode. Effects of {rho}-{omega} interference in X decay are also introduced.