Nonuniversality of Tricritical Behavior

Neutral pion form factor measurement by the NA62 experiment

“…This result is the first observation (at about 5.8 σ significance) of a non-zero TFF slope in the time-like momentum transfer region and represents the more precise π 0 TFF slope measurement to date. The NA62 measurement can be directly compared to those of other experiments [14][15][16][17] obtained from π 0 Dalitz decays, as shown in Fig. 3 (right): the analysed statistics is increased by a factor of ∼10 and the overall precision of the preliminary NA62 result improves the one of previous measurements.…”

Tricritical Points in the Equilibrium Polymerization of Sulfur Solutions

“…These logarithmic corrections are difficult to detect in 3 He-4 He mixtures 15 and vanish 16 in the limit n -°°. Theoretical estimates 14 and Monte Carlo calculations 17 indicate that such corrections may be important for n =1, however, and an estimate along the lines of Ref.…”

Universality of TricriticalHe3-He

“…Yet for the particular case of x being measured along the phase separation curve the amplitude ratio is predicted to be the same as for the concentration x, 3 and hence again universality should apply.…”

“…For our measurements we have used 3 He-4 He mixtures which at saturated vapor pressure display a well-studied tricritical point (TCP) at a temperature T t = 0.867 K and a 3 He concentration x t =0.675. 5 " 9 We have investigated the phase diagram of this system with the pressure/) as an additional variable in order to study the effect of this presumably irrelevant parameter on the critical exponent p and also on the amplitudes given by the shape of the phase separation curve as defined below.…”

“…Since the asymptotic tricritical region, as observed at SVP, is limited to T t -t < 10 mK, 5 ' 8 one has to carry out measurements to within T t -T < 1 mK to cover at least one decade in reduced temperature-quite a small interval compared with the range available for other critical points. Even that very modest requirement, however, is usually hard to meet because measurements in 3 He- 4 He mixtures close to the TCP in general suffer seriously from gravitationally induced concentration gradients. 11 ' 12 This latter problem can be circumvented by determining x + -x. in the immediate neighborhood of the interface of the stratified mixture.…”