Measurement Of The Away Side Of Semi-Inclusive Recoil Jets In Pp Collisions At 5.02TeV With ALICE

It is now generally accepted that the basic units of matter are quarks and gluons,and the normative theory that describes their strong interactions is quantum chromodynamics(QCD).QCD theory has two basic characteristics:asymptotic freedom and confinement.Asymptotic freedom means that when the distance between quarks is closer,the strong interaction between them becomes weak,while confinement means that quarks are generally trapped inside the hadron and we cannot get free quarks.In the 1970s,Li Zhengdao and others suggested that a high temperature,energy density environment similar to the one microseconds after the Big Bang could be created by the method of relativistic heavy ion collision,causing the hadron to deconfined and close to form a new phase of quark matter,called quark gluon plasma(QGP),in order to achieve the observation of free quarks and gluons in the laboratory.This method greatly promotes the development of relativistic heavy ion collision experiments and theoretical.The study of QGP in extremely high temperature and energy density environment can reveal the nature of strong interaction between quarks and gluons,and further deepen people's understanding of the basic physical laws of nature.Under laboratory conditions,we can use large experimental devices such as the Large Hadron Collider(LHC)and the Relativistic Heavy Ion Collider(RHIC)to conduct ultra-relativistic heavy ion collision experiments,creating extremely high temperature and energy density environments in a very short period of time,resulting in the creation of QGP.Although the existence of QGP is extremely short,it expands and cools gradually after its formation,eventually forming an observable final-state hadron.Therefore,in order to study the temporary physical properties of QGP,different QGP signals and probes are continuously proposed and widely studied.This analysis is based on the large heavy ion collider experiment(A Large Ion Collider Experiment,ALICE)in the laboratory to collide particles,looking for the final state particles and the information it carries,and to study the formation process and properties of QGP.The jets used in our analysis is one of the most effective probes to study QGP.In the high-energy nucleon-nucleon collisions,we refer to the process at which the internal transverse momentum of the nucleons shifts significantly in the early stages of a collision as the Hard Scattering process,which produces a large number of high-energy partons,while the jets is defined as a collection of partons whose pseudorapidity and azimuth angles space concentrate within a certain cone angle.Theories predict that the hard scattered partons,when crossing QGP,will be subjected to multiple scattering of partons in the medium,and induce the radiation out of the gluon and lose energy,which leads to the final-state high transverse momentum particles we see in the experiment has a suppression phenomenon relative to the vaccum-like proton-proton collisions,that is,jet quenching.Therefore,the jet quenching phenomenon can not only verify the theoretical prophecy of the perturbation QCD,but also help us understand the evolution of QGP and its properties.Based on proton-proton collision data with an energy of 5.02 TeV obtained by the ALICE experimental detector in 2017,this analysis studies the distribution of semi-inclusive recoil jets by using charged particle triggered jet correlations.In this paper,Charged particle triggers with two different transverse momentum intervals are selected,and the uncorrelated background in the process of jet generation is deducted by subtracting the two recoil jets with different trigger intervals,so as to obtain the distribution of the semi-inclusive recoil jet with relatively clean background,i.e.the distribution of ?recoil and ?(??).At the same time,in view of the detector effect existing in the semi-inclusive recoil jet distribution,we also used Monte Carlo simulation data to revise and compare the corrected results with Monte Carlo predictions to test the accuracy of the theoretical model.On the one hand,we use the ratio of jet yields to different resolution parameters to reflect the collimation information in jet splitting.On the other hand,we also study the distribution of the azimuth angles correlation between the trigger hadrons and recoil jets,which reflects the trend of the distribution width of the correlation angle gradually narrowing with the increase of the transverse momentum range of the recoil jet,which is similar to the simulation results of the MC simulation data.