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Measurement of masses in the [Formula: see text] system by kinematic endpoints in pp collisions at [Formula: see text].

- Eur Phys J C Part Fields (2013)

Bottom Line: A simultaneous measurement of the top-quark, W-boson, and neutrino masses is reported for [Formula: see text] events selected in the dilepton final state from a data sample corresponding to an integrated luminosity of 5.0 fb(-1) collected by the CMS experiment in pp collisions at [Formula: see text].When the neutrino and W-boson masses are constrained to their world-average values, a top-quark mass value of [Formula: see text] is obtained.When such constraints are not used, the three particle masses are obtained in a simultaneous fit.

View Article: PubMed Central - PubMed

Affiliation: Yerevan Physics Institute, Yerevan, Armenia.

ABSTRACT

A simultaneous measurement of the top-quark, W-boson, and neutrino masses is reported for [Formula: see text] events selected in the dilepton final state from a data sample corresponding to an integrated luminosity of 5.0 fb(-1) collected by the CMS experiment in pp collisions at [Formula: see text]. The analysis is based on endpoint determinations in kinematic distributions. When the neutrino and W-boson masses are constrained to their world-average values, a top-quark mass value of [Formula: see text] is obtained. When such constraints are not used, the three particle masses are obtained in a simultaneous fit. In this unconstrained mode the study serves as a test of mass determination methods that may be used in beyond standard model physics scenarios where several masses in a decay chain may be unknown and undetected particles lead to underconstrained kinematics.

No MeSH data available.


Related in: MedlinePlus

(Top) Pull distribution  for the top-quark mass (other masses are fixed) across 150 MC pseudo-experiments. (Bottom) Fit results obtained in MC -only samples generated with MadGraph for various top-quark masses. The best-fit calibration is shown by the solid line and the line of unit slope is shown in the dashed line. Data points are from doubly-constrained fits. The line of unit slope agrees with the fit results with χ2/degree of freedom=10.7/9
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Fig7: (Top) Pull distribution for the top-quark mass (other masses are fixed) across 150 MC pseudo-experiments. (Bottom) Fit results obtained in MC -only samples generated with MadGraph for various top-quark masses. The best-fit calibration is shown by the solid line and the line of unit slope is shown in the dashed line. Data points are from doubly-constrained fits. The line of unit slope agrees with the fit results with χ2/degree of freedom=10.7/9

Mentions: Figure 7, top, shows the pull distribution for the doubly-constrained fit over 150 pseudo-experiments. Extracting a result from each pseudo-experiment involves the methods discussed in Sect. 6.4, and thus the total number of pseudo-experiments required for the study is 150×200. The measured pull mean is 0.15±0.19 and the pull standard deviation is 0.92±0.06, indicating that the fit is unbiased to the level at which it can be measured with the available simulated data. The slightly low standard deviation suggests that the statistical uncertainty may be overestimated; since the systematic uncertainty is significantly larger than the statistical error, we do not make any correction for this. Fig. 7


Measurement of masses in the [Formula: see text] system by kinematic endpoints in pp collisions at [Formula: see text].

- Eur Phys J C Part Fields (2013)

(Top) Pull distribution  for the top-quark mass (other masses are fixed) across 150 MC pseudo-experiments. (Bottom) Fit results obtained in MC -only samples generated with MadGraph for various top-quark masses. The best-fit calibration is shown by the solid line and the line of unit slope is shown in the dashed line. Data points are from doubly-constrained fits. The line of unit slope agrees with the fit results with χ2/degree of freedom=10.7/9
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4371053&req=5

Fig7: (Top) Pull distribution for the top-quark mass (other masses are fixed) across 150 MC pseudo-experiments. (Bottom) Fit results obtained in MC -only samples generated with MadGraph for various top-quark masses. The best-fit calibration is shown by the solid line and the line of unit slope is shown in the dashed line. Data points are from doubly-constrained fits. The line of unit slope agrees with the fit results with χ2/degree of freedom=10.7/9
Mentions: Figure 7, top, shows the pull distribution for the doubly-constrained fit over 150 pseudo-experiments. Extracting a result from each pseudo-experiment involves the methods discussed in Sect. 6.4, and thus the total number of pseudo-experiments required for the study is 150×200. The measured pull mean is 0.15±0.19 and the pull standard deviation is 0.92±0.06, indicating that the fit is unbiased to the level at which it can be measured with the available simulated data. The slightly low standard deviation suggests that the statistical uncertainty may be overestimated; since the systematic uncertainty is significantly larger than the statistical error, we do not make any correction for this. Fig. 7

Bottom Line: A simultaneous measurement of the top-quark, W-boson, and neutrino masses is reported for [Formula: see text] events selected in the dilepton final state from a data sample corresponding to an integrated luminosity of 5.0 fb(-1) collected by the CMS experiment in pp collisions at [Formula: see text].When the neutrino and W-boson masses are constrained to their world-average values, a top-quark mass value of [Formula: see text] is obtained.When such constraints are not used, the three particle masses are obtained in a simultaneous fit.

View Article: PubMed Central - PubMed

Affiliation: Yerevan Physics Institute, Yerevan, Armenia.

ABSTRACT

A simultaneous measurement of the top-quark, W-boson, and neutrino masses is reported for [Formula: see text] events selected in the dilepton final state from a data sample corresponding to an integrated luminosity of 5.0 fb(-1) collected by the CMS experiment in pp collisions at [Formula: see text]. The analysis is based on endpoint determinations in kinematic distributions. When the neutrino and W-boson masses are constrained to their world-average values, a top-quark mass value of [Formula: see text] is obtained. When such constraints are not used, the three particle masses are obtained in a simultaneous fit. In this unconstrained mode the study serves as a test of mass determination methods that may be used in beyond standard model physics scenarios where several masses in a decay chain may be unknown and undetected particles lead to underconstrained kinematics.

No MeSH data available.


Related in: MedlinePlus