Kinematic Fitting for ParticleFlow Detectors at Future Higgs Factories

In many analyses in Higgs, top and electroweak physics, the kinematic reconstruction of the final state is improved by constrained fits. This is a particularly powerful tool at $e^{+}e^{-}$ colliders, where the four-momentum of the initial state is known and can be used to constrain the final state. A crucial ingredient to kinematic fitting is an accurate estimate of the measurement uncertainties, in particular for composed objects like jets. This contribution will show how the particle flow concept, which is a design-driver for most detectors proposed for future Higgs factories, can --- in addition to an excellent jet energy measurement --- provide detailed estimates of the covariance matrices for each individual particle-flow object (PFO) and each individual jet. Combined with information about leptons and secondary vertices in the jets, the kinematic fit enables to correct $b$- and $c$-jets for missing momentum from neutrinos from semi-leptonic heavy quark decays. The correction to the semi-leptonic decays is evaluated using truth-level information and the effects of using reconstructed information are investigated. The impact on the reconstruction of invariant di-jet masses and the resulting improvement in $ZH$ vs $ZZ$ separation will be presented, using the full simulation of the ILD detector, as an example of highly-granular ParticleFlow optimized detector concept

Kinematic Fitting for Particle Flow Detectors at Future Higgs Factories

In many analyses in Higgs, top and electroweak physics, the kinematic reconstruction of the final state is improved by constrained fits. This is a particularly powerful tool at $e^{+}e^{-}$ colliders, where the initial state four-momentum is known and can be employed to constrain the final state. A crucial ingredient to kinematic fitting is an accurate estimate of the measurement uncertainties, in particular for composed objects like jets. This contribution will show how the particle flow concept, which is a design-driver for most detectors proposed for future Higgs factories, can --- in addition to an excellent jet energy measurement --- provide detailed estimates of the covariance matrices for each individual particle flow object (PFO) and each individual jet. Combined with information about leptons and secondary vertices in the jets, the kinematic fit enables to correct $b$- and $c$-jets for missing momentum from neutrinos from semi-leptonic heavy quark decays. The impact on the reconstruction of invariant di-jet masses and the resulting improvement in $ZH$ vs $ZZ$ separation will be presented, using the full simulation of the International Large Detector (ILD), as an example of highly-granular ParticleFlow optimized detector concept

Kinematic Fitting for ParticleFlow Detectors at Future Higgs Factories

In many analyses in Higgs, top and electroweak physics, the kinematic reconstruction of the final state is improved by constrained fits. This is a particularly powerful tool at $e^{+}e^{-}$ colliders, where the initial state four-momentum is known and can be employed to constrain the final state. A crucial ingredient to kinematic fitting is an accurate estimate of the measurement uncertainties, in particular for composed objects like jets. This contribution will show how the particle flow concept, which is a design-driver for most detectors proposed for future Higgs factories, can --- in addition to an excellent jet energy measurement --- provide detailed estimates of the covariance matrices for each individual particle-flow object (PFO) and each individual jet. Combined with information about leptons and secondary vertices in the jets, the kinematic fit enables to correct $b$- and $c$-jets for missing momentum from neutrinos from semi-leptonic heavy quark decays. The impact on the reconstruction of invariant di-jet masses and the resulting improvement in $ZH$ vs $ZZ$ separation will be presented, using the full simulation of the ILD detector, as an example of highly-granular ParticleFlow optimized detector concept

Conceptual aspects for the improvement of the reconstruction of bb- and cc-jets at e+e−e^{+}e^{-} Higgs Factories with ParticleFlow detectors

The Higgs boson decay modes to $b$ and $c$ quarks are crucial for many Higgs precision measurements. The presence of semileptonic decays in the jets originating from $b$ and $c$ quarks causes missing energy due to the undetectable neutrinos. A correction for the missing neutrino momenta can be derived from the kinematics of the decay up to a two-fold ambiguity. The correct solution can be identified by a kinematic fit, which exploits the well-known initial state at an $e^{+}e^{-}$ collider by adjusting the measured quantities within their uncertainties to fulfill the kinematic constraints. The ParticleFlow concept, based on the reconstruction of individual particles in a jet allows understanding the individual jet-level uncertainties at an unprecedented level. The modeling of the jet uncertainties and the resulting fit performance will be discussed for the example of the ILD detector. Applied to $H\rightarrow b\bar{b}/c\bar{c}$ events, the combination of the neutrino correction with the kinematic fit improves the Higgs mass reconstruction significantly, both in terms of resolution and peak position

Kinematic Fitting for ParticleFlow Detectors at Future Higgs Factories

In many analyses in Higgs, top and electroweak physics, the kinematic reconstruction of the final state is improved by constrained fits. This is a particularly powerful tool at $e^{+}e^{-}$ colliders, where the initial state four-momentum is known and can be employed to constrain the final state. A crucial ingredient to kinematic fitting is an accurate estimate of the measurement uncertainties, in particular for composed objects like jets. This contribution will show how the particle flow concept, which is a design-driver for most detectors proposed for future Higgs factories, can --- in addition to an excellent jet energy measurement --- provide detailed estimates of the covariance matrices for each individual particle-flow object (PFO) and each individual jet. Combined with information about leptons and secondary vertices in the jets, the kinematic fit enables to correct $b$- and $c$-jets for missing momentum from neutrinos from semi-leptonic heavy quark decays. The impact on the reconstruction of invariant di-jet masses and the resulting improvement in $ZH$ vs $ZZ$ separation will be presented, using the full simulation of the ILD detector concept

Conceptual aspects for the improvement of the reconstruction of bb- and cc-jets at e+e−e^{+}e^{-} Higgs Factories with ParticleFlow detectors

The Higgs boson decay modes to $b$ and $c$ quarks are crucial for many Higgs precision measurements. The presence of semileptonic decays in the jets originating from $b$ and $c$ quarks causes missing energy due to the undetectable neutrinos. A correction for the missing neutrino momenta can be derived from the kinematics of the decay up to a two-fold ambiguity. The correct solution can be identified by a kinematic fit, which exploits the well-known initial state at an $e^{+}e^{-}$ collider by adjusting the measured quantities within their uncertainties to fulfill the kinematic constraints. The ParticleFlow concept, based on the reconstruction of individual particles in a jet allows understanding the individual jet-level uncertainties at an unprecedented level. The modeling of the jet uncertainties and the resulting fit performance will be discussed for the example of the ILD detector. Applied to $H\rightarrow b\bar{b}/c\bar{c}$ events, the combination of the neutrino correction with the kinematic fit improves the Higgs mass reconstruction significantly, both in terms of resolution and peak position

Reconstruction of bb- and cc- jets at e+e−e^{+}e^{-} Higgs Factories with ParticleFlow detectors

The Higgs boson decay modes to heavy $b$ and $c$ quarks are crucial for the Higgs physics studies. The presence of semileptonic decays in the jets originating from $b$ and $c$ quarks causes missing energy due to the undetectable neutrinos. A correction for the missing neutrino momenta can be derived from the decay kinematics up to a two-fold ambiguity. The correct solution can be identified by a kinematic fit, which exploits the well-known initial state at an $e^{-}e^{+}$ collider by adjusting the measured quantities within their uncertainties to fulfill the kinematic constraints. The ParticleFlow concept, based on reconstruction of individual particles in a jet allows to understand the individual jet-level uncertainties at an unprecedented level. The modeling of the jet uncertainties and the resulting fit performance will be discussed for the example of the ILD detector. Applied to $H\rightarrow b\bar{b}/c\bar{c}$ events, the combination of the neutrino correction with the kinematic fit improves the Higgs mass reconstruction significantly, both in terms of resolution and peak position

Reconstruction of bb- and cc- jets at e+e−e^{+}e^{-} Higgs Factories with ParticleFlow detectors

The Higgs boson decay modes to $b$ and $c$ quarks are crucial for many Higgs precision measurements. The presence of semileptonic decays in the jets originating from $b$ and $c$ quarks causes missing energy due to the undetectable neutrinos. A correction for the missing neutrino momenta can be derived from the kinematics of the decay up to a two-fold ambiguity. The correct solution can be identified by a kinematic fit, which exploits the well-known initial state at an $e^{+}e^{-}$ collider by adjusting the measured quantities within their uncertainties to fulfill the kinematic constraints. The ParticleFlow concept, based on the reconstruction of individual particles in a jet allows understanding the individual jet-level uncertainties at an unprecedented level. The modeling of the jet uncertainties and the resulting fit performance will be discussed for the example of the ILD detector. Applied to $H\rightarrow b\bar{b}/c\bar{c}$ events, the combination of the neutrino correction with the kinematic fit improves the Higgs mass reconstruction significantly, both in terms of resolution and peak position