This study presents the first measurement of the f$_{1}$(1285) resonance using the ALICE detector in inelastic proton-proton collisions at a center-of-mass energy of 13 TeV. The resonance is reconstructed at midrapidity ($|y| <~$ 0.5) through the hadronic decay channel f$_{1} (1285) \rightarrow \mathrm{K^{0}_{S} K^{\pm}\pi^{\mp}}$. Key measurements include the determination of its mass, transverse-momentum integrated yield, and average transverse momentum. Additionally, the ratio of the transverse-momentum integrated yield of f$_{1}$(1285) to pion is compared with calculations from the canonical statistical hadronization model. The model calculation, assuming a zero total strangeness content for f$_{1}$(1285), reproduces the data within 1$\sigma$ deviation, shedding light on the quark composition of f$_{1}$(1285).
Phys. Lett. B 866 (2025) 139562
HEP Data
e-Print: arXiv:2409.11936 | PDF | inSPIRE
CERN-EP-2024-239
Figure group
Figure 1
\ Like- and unlike-sign (left) and the like-sign-subtracted (right) invariant massdistribution of \KS K$\pi$ triplets in $|y|$ 0.5 in minimum-bias pp collisions at \s = 13 TeV. The subtracted distribution is fitted with the function defined by Eq. ???, and the dotted blue line describes the residual background distribution, which is given by Eq. ???. |   |
Figure 3
\ Measured \fone\xspace mass as a function of \pt at midrapidity ($|y|$ 0.5) in minimum-bias pp collisions at \ENthirteen. The statistical and systematic uncertainties are shown as bars and boxes, respectively. The blue band represents the world-average value for the mass of \fone\xspace having an uncertainty of 0.5 MeV/$c^{2}$. |  |
Figure 4
\ \pt-differential yield of \fone\xspace measured at midrapidity ($|y|$ 0.5) in inelastic pp collisions at \ENthirteen. The statistical and systematic uncertainties are shown as bars and boxes, respectively. The data points are fitted using a Levy--Tsallis function and shown by the red dashed line. The BR uncertainty for \foneDC\xspace is 0.1\%. |  |
Figure 5
\ Average transverse momentum of light-flavor hadrons as a function of hadron mass at midrapidity ($|y|$ 0.5) in inelastic pp collisions at \ENthirteen. The statistical and systematic uncertainties are shown as bars and boxes, respectively. The blue dotted lines are linear fits to the data points. |  |
Figure 6
\ The transverse-momentum-integrated yield ratio of $\phi$/$\pi$ (left) and \foneshort/$\pi$ (right) measured in inelastic pp collisions at \ENthirteen. The statistical and systematic uncertainties on the data points are shown as bars and boxes, respectively. The black solid and dotted lines represent the calculations from the $\gamma_{\rm S}$CSM with different strangeness content of $\phi$ and \foneshort\xspace mesons. |  |