A general procedure for detector–response correction of higher order cumulants

Nonaka, T.; Kitazawa, Masakiyo

doi:10.1016/j.nima.2018.08.013

Cited by 23 publications

(13 citation statements)

References 34 publications

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“…Some analytical formulas have been proposed to correct the measured cumulants with the assumption that the response function of the efficiency follows the binomial distribution [14,[16][17][18][19][20][21][22]. Recently, a few attempts to understand and correct for the possible non-binomial efficiencies have been discussed [11,23,24], but there are still large systematic uncertainties arising from how to determine the detector-response functions. The efficiency correction with the binomial assumption is thus still important.…”

Section: Introductionmentioning

confidence: 99%

Efficiency correction for cumulants of multiplicity distributions based on track-by-track efficiency

Luo

Nonaka

2019

Phys. Rev. C

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Section: Introductionmentioning

confidence: 99%

Efficiency correction for cumulants of multiplicity distributions based on track-by-track efficiency

Luo

Nonaka

2019

Phys. Rev. C

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“…( 24). The red symbols correspond to the "standard" efficiency correction (13), which is applicable only for the case of non-overlapping particles. The horizontal dashed line corresponds to the true value of Σ 1,1 Np,Q + / Np = 1.1.…”

Section: A Poisson Distributed Particlesmentioning

confidence: 99%

“…in [9]). However, if W D (n, N ) can be approximated by a binomial distribution -a reasonably good approximation in a number of cases (see [10,11]) -the relevant formulas for the efficiency corrections of cumulants can and have been derived [6,7,12,13]. However, certain subtleties arise when efficiency corrections are performed for off-diagonal cumulants, such as the correlation of net-proton or net-kaon number with the net-charge number.…”

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confidence: 99%

Efficiency corrections for factorial moments and cumulants of overlapping sets of particles

Vovchenko,

Koch

2021

Preprint

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In this note we discuss subtleties associated with the efficiency corrections for measurements of off-diagonal cumulants and factorial moments for a situation when one deals with overlapping sets of particles, such as correlations between numbers of protons and positively charged particles. We present the efficiency correction formulas for the case when the detection efficiencies follow a binomial distribution. I. INTRODUCTIONFluctuations of conserved charges as a probe of the phase structure of strongly interacting matter have recently received considerable interest theoretically as well as experimentally (for a recent review, see [1]). For example, higher order cumulants of the net baryon density are sensitive to the existence of a critical point [2], and may also provide insights about the chiral criticality governing the cross-over transition at vanishing baryochemical potential [3]. The so-called off-diagonal cumulants, i.e. correlations between two different conserved charges, such as baryon number and strangeness, on the other hand, provide insight about the effective degrees of freedom in the medium [4,5].Experimentally, these cumulants are measured by analyzing event-by-event distributions of particles produced in heavy-ion collisions. For these measurements to reveal the true fluctuations of the system created in these collisions, one needs to take into account and remove fluctuations induced by the detector measurement process itself. These detector induced fluctuations, often referred to as efficiency fluctuations [6-8], arise from the finite detection probability W D (n, N ) of an actual detector, where W D (n, N ) is the probability to observe n particles given N ≥ n particles in an event. The probability distribution of observed particles, p(n), is related to the distribution of true particles, P (N ), by(1)Consequently, the cumulants of the observed distribution p(n) differ from those of the true distribution, P (N ). Therefore, an unfolding procedure is needed, which mathematically corresponds to finding the inverse of W D (n, N ). This is not an easy task in general (see discussion e.g. in [9]). However, if W D (n, N ) can be approximated by a binomial distribution -a reasonably good approximation in a number of cases (see [10,11]) -the relevant formulas for the efficiency corrections of cumulants can and have been derived [6,7,12,13]. However, certain subtleties arise when efficiency corrections are performed for off-diagonal cumulants, such as the correlation of net-proton or net-kaon number with the net-charge number. These subtleties have not yet been addressed in the literature. It is the purpose of this note to discuss and provide the necessary efficiency correction formulas. These may be useful for the ongoing and future heavy-ion experiments, in particular as an effort to measure such off-diagonal cumulants is underway (see e.g. [14]).

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“…One possible method is moment expansion proposed in Ref. [20], where detectorresponse matrices are utilized to correct cumulants. In addition, experimental attempts are ongoing to get cumulants corrected for possible non-binomial effects by reconstructing distribution itself [7,21].…”

Section: • Detector Efficiencymentioning

confidence: 99%

Reconstructing particle number distributions with convoluting volume fluctuations

Esumi,

Nakagawa,

Nonaka

2020

Preprint

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We propose the methods to reconstruct the net-particle distributions with and without excluding the initial volume fluctuations. It enables us to correct for detector effects and initial volume fluctuations simultaneously under the assumption of the independent particle production (IPP) model or any particle production mechanism. Our study suggests a tool to investigate possible two-component structure of net-proton distribution in Au+Au collisions at √ sNN = 7.7 GeV as signature of the first-order phase transition or critical end point [1,2].

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A general procedure for detector–response correction of higher order cumulants

Cited by 23 publications

References 34 publications

Efficiency correction for cumulants of multiplicity distributions based on track-by-track efficiency

Efficiency correction for cumulants of multiplicity distributions based on track-by-track efficiency

Efficiency corrections for factorial moments and cumulants of overlapping sets of particles

Reconstructing particle number distributions with convoluting volume fluctuations

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