The transition of neutron to anti-neutron might be the first observed signal of the baryon instab... more The transition of neutron to anti-neutron might be the first observed signal of the baryon instability long-awaited in Grand Unification models and required for the explanation of baryon asymmetry in the universe. A newly-proposed experiment to search for neutron-antineutron transitions at High Flux Isotope Reactor at Oak Ridge National Laboratory can improve the discovery potential by factor of N 1,000 relative to the existing limits. Further prospects of n + ii search are also discussed in this paper.
Experimental observation of nucleon instability is one of the missing key components required for... more Experimental observation of nucleon instability is one of the missing key components required for the explanation of baryon asymmetry of the universe. Proton decays with the modes and rates predicted by(B−L)-conserving schemes of Grand Unification are not observed experimentally. There are reasons to believe that (B−L) might not be conserved in nature, thus leading to the nucleon decay into lepton+(X) and to phenomena such as Majorana masses of neutrinos, neutrinoless double-beta decays, and most spectacularly to the transitions of neutron to anti-neutron. The energy scale where (B−L) violation takes place cannot be predicted by theory and therefore has to be explored by experiments. Different experimental approaches to searching for (B−L)-violating transition of neutron to antineutron are discussed in this paper. Most powerful search for n →n can be performed in a new reactor-based experiment at HFIR/ORNL where sensitivity can be ∼ 1,000 times higher than in the previous experiments.
Fundamental Physics with Pulsed Neutron Beams, 2001
Experimental observation of nucleon instability is one of the key missing components required for... more Experimental observation of nucleon instability is one of the key missing components required for the explanation of baryon asymmetry of the universe. Proton decays with the modes and rates predicted by the original (B−L) conserving SU(5) grand unification scheme are not observed experimentally. There are reasons to believe that (B−L) might not be conserved in nature, thus leading to the nucleon decay into lepton + (X) and to phenomena such as Majorana masses of neutrinos, neutrinoless double-beta decays, and most spectacularly the transitions of neutron to antineutron. The energy scale where these processes may occur is far beyond the reach of contemporary colliders. This scale is not predicted by theory therefore the existence of corresponding processes must be explored experimentally. In this paper we discuss motivation and a new experimental approach to searching for (B−L) violating transition of neutron to antineutron. A new search for n n → can be performed in a reactor-based experiment at HFIR/ORNL with a sensitivity ~1000 times higher than in previous experiments.
We thank the many people at the SSC Laboratory who dedicated themselves to the successful complet... more We thank the many people at the SSC Laboratory who dedicated themselves to the successful completion of the GEM TDR. Very special thanks go to those staff members who led the production with incomparable professionalism, skill, and stamina.
We report on the measurement of W-boson pair-production with the L3 detector at LEP at a centre-o... more We report on the measurement of W-boson pair-production with the L3 detector at LEP at a centre-of-mass energy of 161.34 GeV. In a data sample corresponding to a total luminosity of 11 pb 1 , we select four-fermion events with high invariant masses of pairs of hadronic jets or leptons. Combining all nal states, the measured total cross section for W-pair production is: WW = 2:89 +0:81 0:70 (stat:) 0:14 (syst:) pb. Within the Standard Model, this corresponds to a mass of the W boson of: M W = 80:80 +0:48 0:42 (exp:) 0:03 (LEP) GeV. Limits on anomalous triplevector-boson couplings are derived.
Results from the PHENIX experiment for the first RHIC run with Au-Au collisions at √ s N N = 130 ... more Results from the PHENIX experiment for the first RHIC run with Au-Au collisions at √ s N N = 130 GeV are presented. The systematic variation with centrality of charged particle multiplicity, transverse energy, elliptic flow, identified particle spectra and yield ratios, and production of charged particles and π 0 's at high transverse momenta are presented. Results on two-pion correlations and electron spectra are also provided, along with a discussion of plans for the second run at RHIC.
We present the initial design of a very large 1 kton liquid scintillator detector to be installed... more We present the initial design of a very large 1 kton liquid scintillator detector to be installed in the underground cavity where Kamiokande used to be. The experiment is optimized to detect low-energy anti-neutrinos and it will perform unique measurements in the elds of neutrino physics, geophysics and astrophysics. One of the initial goals will beto perform a very long baseline oscillation experiment using a large numberof nuclear reactors. Such an experiment will be sensitive to neutrino masses as low a s m 2 ' 7 10 ;6 eV 2 attacking, for the rst time with a laboratory measurement, some of the possible solutions to the \solar neutrino anomaly". This can beconsidered the \ultimate" neutrino mass test using the oscillation technique. The observation of neutrinos from the Earth, supernovae, atmosphere and nucleon decay will also bepart of a very rich initial program, while in a later stage the observation of solar neutrinos and other channels requiring ultra-low background will become the main focus. KamLAND is conceived as a \scalable" detector that will be able to start in a very short time to deliver results on a numberof essential physics issues that only require present-day technology. This rst running period will also establish backgrounds and detector requirements for a second ultra-low background running phase.
For neutrons bound inside nuclei, baryon instability can manifest itself as a decay into undetect... more For neutrons bound inside nuclei, baryon instability can manifest itself as a decay into undetectable particles (e.g., n → ννν), i.e., as a disappearance of a neutron from its nuclear state. If electric charge is conserved, a similar disappearance is impossible for a proton. The existing experimental lifetime limit for neutron disappearance is 4-7 orders of magnitude lower than the lifetime limits with detectable nucleon decay products in the final state [1]. In this paper we calculated the spectrum of nuclear de-excitations that would result from the disappearance of a neutron or two neutrons from 12 C. We found that some de-excitation modes have signatures that are advantageous for detection in the modern high-mass, low-background, and low-threshold underground detectors, where neutron disappearance would result in a characteristic sequence of time-and space-correlated events. Thus, in the KamLAND detector [2], a time-correlated triple coincidence of a prompt signal, a captured neutron, and a β + decay of the residual nucleus, all originating from the same point in the detector, will be a unique signal of neutron disappearance allowing searches for baryon instability with sensitivity 3-4 orders of magnitude beyond the present experimental limits.
The spectral functions of the vector current and the axial-vector current have been measured in h... more The spectral functions of the vector current and the axial-vector current have been measured in hadronic τ decays using the OPAL detector at LEP. Within the framework of the Operator Product Expansion a simultaneous determination of the strong coupling constant α s , the non-perturbative operators of dimension 6 and 8 and of the gluon condensate has been performed. Different perturbative descriptions have been compared to the data. The Contour Improved Fixed Order Perturbation Theory gives α s (m 2 τ) = 0.348±0.009 exp ±0.019 theo at the τ-mass scale and α s (m 2 Z) = 0.1219±0.0010 exp ±0.0017 theo at the Z 0-mass scale. The values obtained for α s (m 2 Z) using Fixed Order Perturbation Theory or Renormalon Chain Resummation are 2.3 % and 4.1 % smaller, respectively. The 'running' of the strong coupling between s 0 ≃ 1.3 GeV 2 and s 0 = m 2 τ has been tested from direct fits to the integrated differential hadronic decay rate R τ (s 0). A test of the saturation of QCD sum rules at the τ-mass scale has been performed.
The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source foc... more The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source focusing on searches for baryon number violation via processes in which neutrons convert to antineutrons. This paper outlines the computing and detector simulation framework for the HIBEAM/NNBAR program. The simulation is based on predictions of neutron flux and neutronics together with signal and background generation. A range of diverse simulation packages are incorporated, including Monte Carlo transport codes, neutron ray-tracing simulation packages, and detector simulation software. The common simulation package in which these elements are interfaced together is discussed. Data management plans and triggers are also described.
The possibility of relatively fast neutron oscillations into a mirror neutron state is not exclud... more The possibility of relatively fast neutron oscillations into a mirror neutron state is not excluded experimentally when a mirror magnetic field is considered. Direct searches for the disappearance of neutrons into mirror neutrons in a controlled magnetic field have previously been performed using ultracold neutrons, with some anomalous results reported. We describe a technique using cold neutrons to perform a disappearance and regeneration search, which would allow us to unambiguously identify a possible oscillation signal. An experiment using the existing General Purpose-Small Angle Neutron Scattering instrument at the High Flux Isotope Reactor at Oak Ridge National Laboratory will have the sensitivity to fully explore the parameter space of prior ultracold neutron searches and confirm or refute previous claims of observation. This instrument can also conclusively test the validity of recently suggested oscillation-based explanations for the neutron lifetime anomaly.
Physical Review D - Particles, Fields, Gravitation and Cosmology, 2013
Double Chooz is unique among modern reactor-based neutrino experiments studying " e disappearance... more Double Chooz is unique among modern reactor-based neutrino experiments studying " e disappearance in that data can be collected with all reactors off. In this paper, we present data from 7.53 days of reactoroff running. Applying the same selection criteria as used in the Double Chooz reactor-on oscillation analysis, a measured background rate of 1:0 AE 0:4 events/day is obtained. The background model for accidentals, cosmogenic-n-emitting isotopes, fast neutrons from cosmic muons, and stopped-decays used in the oscillation analysis is demonstrated to be correct within the uncertainties. Kinematic distributions of the events, which are dominantly cosmic-ray-produced correlated-background events, are provided. The background rates are scaled to the shielding depths of two other reactor-based oscillation experiments, Daya Bay and RENO.
We h a v e measured the forward-backward asymmetry in e + e ! b b and e + e ! c c processes using... more We h a v e measured the forward-backward asymmetry in e + e ! b b and e + e ! c c processes using hadronic events containing muons or electrons. The data sample corresponds to 410,000 hadronic decays of the Z 0. F rom a t to the single lepton and dilepton p and p T spectra, we determine
The transition of neutron to anti-neutron might be the first observed signal of the baryon instab... more The transition of neutron to anti-neutron might be the first observed signal of the baryon instability long-awaited in Grand Unification models and required for the explanation of baryon asymmetry in the universe. A newly-proposed experiment to search for neutron-antineutron transitions at High Flux Isotope Reactor at Oak Ridge National Laboratory can improve the discovery potential by factor of N 1,000 relative to the existing limits. Further prospects of n + ii search are also discussed in this paper.
Experimental observation of nucleon instability is one of the missing key components required for... more Experimental observation of nucleon instability is one of the missing key components required for the explanation of baryon asymmetry of the universe. Proton decays with the modes and rates predicted by(B−L)-conserving schemes of Grand Unification are not observed experimentally. There are reasons to believe that (B−L) might not be conserved in nature, thus leading to the nucleon decay into lepton+(X) and to phenomena such as Majorana masses of neutrinos, neutrinoless double-beta decays, and most spectacularly to the transitions of neutron to anti-neutron. The energy scale where (B−L) violation takes place cannot be predicted by theory and therefore has to be explored by experiments. Different experimental approaches to searching for (B−L)-violating transition of neutron to antineutron are discussed in this paper. Most powerful search for n →n can be performed in a new reactor-based experiment at HFIR/ORNL where sensitivity can be ∼ 1,000 times higher than in the previous experiments.
Fundamental Physics with Pulsed Neutron Beams, 2001
Experimental observation of nucleon instability is one of the key missing components required for... more Experimental observation of nucleon instability is one of the key missing components required for the explanation of baryon asymmetry of the universe. Proton decays with the modes and rates predicted by the original (B−L) conserving SU(5) grand unification scheme are not observed experimentally. There are reasons to believe that (B−L) might not be conserved in nature, thus leading to the nucleon decay into lepton + (X) and to phenomena such as Majorana masses of neutrinos, neutrinoless double-beta decays, and most spectacularly the transitions of neutron to antineutron. The energy scale where these processes may occur is far beyond the reach of contemporary colliders. This scale is not predicted by theory therefore the existence of corresponding processes must be explored experimentally. In this paper we discuss motivation and a new experimental approach to searching for (B−L) violating transition of neutron to antineutron. A new search for n n → can be performed in a reactor-based experiment at HFIR/ORNL with a sensitivity ~1000 times higher than in previous experiments.
We thank the many people at the SSC Laboratory who dedicated themselves to the successful complet... more We thank the many people at the SSC Laboratory who dedicated themselves to the successful completion of the GEM TDR. Very special thanks go to those staff members who led the production with incomparable professionalism, skill, and stamina.
We report on the measurement of W-boson pair-production with the L3 detector at LEP at a centre-o... more We report on the measurement of W-boson pair-production with the L3 detector at LEP at a centre-of-mass energy of 161.34 GeV. In a data sample corresponding to a total luminosity of 11 pb 1 , we select four-fermion events with high invariant masses of pairs of hadronic jets or leptons. Combining all nal states, the measured total cross section for W-pair production is: WW = 2:89 +0:81 0:70 (stat:) 0:14 (syst:) pb. Within the Standard Model, this corresponds to a mass of the W boson of: M W = 80:80 +0:48 0:42 (exp:) 0:03 (LEP) GeV. Limits on anomalous triplevector-boson couplings are derived.
Results from the PHENIX experiment for the first RHIC run with Au-Au collisions at √ s N N = 130 ... more Results from the PHENIX experiment for the first RHIC run with Au-Au collisions at √ s N N = 130 GeV are presented. The systematic variation with centrality of charged particle multiplicity, transverse energy, elliptic flow, identified particle spectra and yield ratios, and production of charged particles and π 0 's at high transverse momenta are presented. Results on two-pion correlations and electron spectra are also provided, along with a discussion of plans for the second run at RHIC.
We present the initial design of a very large 1 kton liquid scintillator detector to be installed... more We present the initial design of a very large 1 kton liquid scintillator detector to be installed in the underground cavity where Kamiokande used to be. The experiment is optimized to detect low-energy anti-neutrinos and it will perform unique measurements in the elds of neutrino physics, geophysics and astrophysics. One of the initial goals will beto perform a very long baseline oscillation experiment using a large numberof nuclear reactors. Such an experiment will be sensitive to neutrino masses as low a s m 2 ' 7 10 ;6 eV 2 attacking, for the rst time with a laboratory measurement, some of the possible solutions to the \solar neutrino anomaly". This can beconsidered the \ultimate" neutrino mass test using the oscillation technique. The observation of neutrinos from the Earth, supernovae, atmosphere and nucleon decay will also bepart of a very rich initial program, while in a later stage the observation of solar neutrinos and other channels requiring ultra-low background will become the main focus. KamLAND is conceived as a \scalable" detector that will be able to start in a very short time to deliver results on a numberof essential physics issues that only require present-day technology. This rst running period will also establish backgrounds and detector requirements for a second ultra-low background running phase.
For neutrons bound inside nuclei, baryon instability can manifest itself as a decay into undetect... more For neutrons bound inside nuclei, baryon instability can manifest itself as a decay into undetectable particles (e.g., n → ννν), i.e., as a disappearance of a neutron from its nuclear state. If electric charge is conserved, a similar disappearance is impossible for a proton. The existing experimental lifetime limit for neutron disappearance is 4-7 orders of magnitude lower than the lifetime limits with detectable nucleon decay products in the final state [1]. In this paper we calculated the spectrum of nuclear de-excitations that would result from the disappearance of a neutron or two neutrons from 12 C. We found that some de-excitation modes have signatures that are advantageous for detection in the modern high-mass, low-background, and low-threshold underground detectors, where neutron disappearance would result in a characteristic sequence of time-and space-correlated events. Thus, in the KamLAND detector [2], a time-correlated triple coincidence of a prompt signal, a captured neutron, and a β + decay of the residual nucleus, all originating from the same point in the detector, will be a unique signal of neutron disappearance allowing searches for baryon instability with sensitivity 3-4 orders of magnitude beyond the present experimental limits.
The spectral functions of the vector current and the axial-vector current have been measured in h... more The spectral functions of the vector current and the axial-vector current have been measured in hadronic τ decays using the OPAL detector at LEP. Within the framework of the Operator Product Expansion a simultaneous determination of the strong coupling constant α s , the non-perturbative operators of dimension 6 and 8 and of the gluon condensate has been performed. Different perturbative descriptions have been compared to the data. The Contour Improved Fixed Order Perturbation Theory gives α s (m 2 τ) = 0.348±0.009 exp ±0.019 theo at the τ-mass scale and α s (m 2 Z) = 0.1219±0.0010 exp ±0.0017 theo at the Z 0-mass scale. The values obtained for α s (m 2 Z) using Fixed Order Perturbation Theory or Renormalon Chain Resummation are 2.3 % and 4.1 % smaller, respectively. The 'running' of the strong coupling between s 0 ≃ 1.3 GeV 2 and s 0 = m 2 τ has been tested from direct fits to the integrated differential hadronic decay rate R τ (s 0). A test of the saturation of QCD sum rules at the τ-mass scale has been performed.
The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source foc... more The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source focusing on searches for baryon number violation via processes in which neutrons convert to antineutrons. This paper outlines the computing and detector simulation framework for the HIBEAM/NNBAR program. The simulation is based on predictions of neutron flux and neutronics together with signal and background generation. A range of diverse simulation packages are incorporated, including Monte Carlo transport codes, neutron ray-tracing simulation packages, and detector simulation software. The common simulation package in which these elements are interfaced together is discussed. Data management plans and triggers are also described.
The possibility of relatively fast neutron oscillations into a mirror neutron state is not exclud... more The possibility of relatively fast neutron oscillations into a mirror neutron state is not excluded experimentally when a mirror magnetic field is considered. Direct searches for the disappearance of neutrons into mirror neutrons in a controlled magnetic field have previously been performed using ultracold neutrons, with some anomalous results reported. We describe a technique using cold neutrons to perform a disappearance and regeneration search, which would allow us to unambiguously identify a possible oscillation signal. An experiment using the existing General Purpose-Small Angle Neutron Scattering instrument at the High Flux Isotope Reactor at Oak Ridge National Laboratory will have the sensitivity to fully explore the parameter space of prior ultracold neutron searches and confirm or refute previous claims of observation. This instrument can also conclusively test the validity of recently suggested oscillation-based explanations for the neutron lifetime anomaly.
Physical Review D - Particles, Fields, Gravitation and Cosmology, 2013
Double Chooz is unique among modern reactor-based neutrino experiments studying " e disappearance... more Double Chooz is unique among modern reactor-based neutrino experiments studying " e disappearance in that data can be collected with all reactors off. In this paper, we present data from 7.53 days of reactoroff running. Applying the same selection criteria as used in the Double Chooz reactor-on oscillation analysis, a measured background rate of 1:0 AE 0:4 events/day is obtained. The background model for accidentals, cosmogenic-n-emitting isotopes, fast neutrons from cosmic muons, and stopped-decays used in the oscillation analysis is demonstrated to be correct within the uncertainties. Kinematic distributions of the events, which are dominantly cosmic-ray-produced correlated-background events, are provided. The background rates are scaled to the shielding depths of two other reactor-based oscillation experiments, Daya Bay and RENO.
We h a v e measured the forward-backward asymmetry in e + e ! b b and e + e ! c c processes using... more We h a v e measured the forward-backward asymmetry in e + e ! b b and e + e ! c c processes using hadronic events containing muons or electrons. The data sample corresponds to 410,000 hadronic decays of the Z 0. F rom a t to the single lepton and dilepton p and p T spectra, we determine
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Papers by Yuri Kamyshkov