Cross sections of 𝜂 mesons in 𝑝 +𝑝 collisions at forward rapidity at √𝑠 =500  GeV and central rapidity at √𝑠 =510  GeV

Abstract

We present the first measurements of the forward and midrapidity 𝜂-meson cross sections from 𝑝 +𝑝 collisions at √𝑠 =500 and 510 GeV, respectively. We also report the midrapidity 𝜂/𝜋0 ratio at 510 GeV. The forward cross section is measured differentially in 𝜂-meson transverse momentum (𝑝𝑇) from 1.0 to 6.5  GeV/𝑐 for pseudorapidity 3.0 <|𝜂| <3.8. The midrapidity cross section is measured from 3.5 to 44  GeV/𝑐 for pseudorapidity |𝜂| <0.35. Both cross sections serve as critical inputs to an updated global analysis of the 𝜂-meson fragmentation functions.