117312086
Search for fast particles produced at large lab angles at NAL
An experiment is proposed to look for charged particles emitted at large lab angles that are normally forbidden kinematically. These particles if found would correspond to hitherto unobserved events such as the production of particles with imaginary mass values (''tachyons''). Also, they wish to look for fractionally-charged particles produced at these angles. These particles, if found, would correspond to strongly-bound quark-quark states formed in a dissociation of the target nucleon. The detection system will consist of wire-chambers, dE/dx and time-of-flight counters. The basic hardware is under construction and the final system will be ready for test runs at a lower-energy machine in six months. The detection telescope will view interactions of the primary proton beam from backward (in lab) directions and the first choice experimental site is the straight section B with a thin internal target. They would like to use the highest available beam at NAL and since the beam transport and intensity requirements are very minimal, they will be able to run parasitically during the tuning periods of the NAL machine in the next year. The machine time required for this experiment is about three months.
117351482
Bubble chamber study of (10÷100) GeV cosmic-ray muons at all zenith angles
SummaryCosmic-ray muons have been studied by analysis of tracks recorded in a large high-field heavy-liquid bubble chamber. From a sample of 50 000 pictures approximately 2 000 muons with energies above 10 GeV were examined for energy and zenith-angle distributions over the complete range from 0° to 90°. In the vertical direction the integral spectrum up to energies exceeding 100 GeV is consistent with depth intensity data and somewhat higher than observed in unshielded vertical magnetic spectrometers. At other zenith angles we find the expected variations, which approach a cos2ϑ attenuation for muons in the 10 GeV region, and tend towards a secϑ enhancement for muon energies above 100 GeV.RiassuntoSi sono studiati i muoni dei raggi cosmici analizzando le tracce fotografate in una grande camera a bolle a liquido pesante con forte campo magnetico. Da un campione di 50 000 fotogrammi si sono esaminati approssimativamente 2 000 muoni con energie superiori a 10 GeV per le distribuzioni di energia e dell’angolo zenitale nell’intero intervallo da 0° a 90°. Nella direzione verticale lo spettro integrale fino ad energie superiori ai 100 GeV è coerente con i dati sull’intensità in profondità ed è leggermente superiore a quello osservato in spettrometri magnetici verticali non schermati. Ad altri angoli zenitali si trovano le variazioni previste, che approssimano una attenuazione del tipo cos2ϑ per muoni nella regione di 10 GeV, e tendono verso un incremento del tipo secϑ per energie dei muoni al di sopra dei 100 GeV.РеэюмеБыли исследованы мюоны в космических лучах посредством аналиэа треков, эарегистрированных в пуэырьковой камере с тяжелой жидкостью, помешенной в сильном поле. Иэ выборки 50000 снимков были исследованы приблиэительно 2000 мюонов с знергиями около 10 ГзВ для получения знергетических распределений и распределений по эенитному углу во всей области углов от 0° до 90°. В вертикальном направлении интегральный спектр вплоть до знергий, превыщаюших 100 ГзВ, согласуется с данными глубинной интенсивности и до некоторой степени выще, чем наблюденный в незкранированных вертикальных магнитных спектрометрах. При других эенитных углах мы обнаружили предполагаемые иэменения, которые почти похожи на ослабление соs2 ϑ для мюонов в области 10 ГзВ и стремятся к увеличению вес ϑ для знергий мюонов выще 100 ГзВ.
122338380
COSMIC RAY MUONS FROM LOW GALACTIC LATITUDE
Occasional spurious tracks are found on photographs taken during routine observations with the 40-inch heavy-liquid bubble chamber (HLBC) at the Argonne National Laboratory (Roe, Sinclair, and Vander Vilde 1964). These tracks are caused by cosmic ray muons, and are rather similar to streaks caused by meteors on photographs of the sky. The HLBC is located at Ν 41°42'03" latitude and W 87°59'24" longitude, and at an altitude of 227.38 meters above sea level. It has a field of view in the form of a strip 50° wide centered on the north-zenith-south meridian. The strip extends from horizon to horizon. As the earth turns, 87 percent of the celestial sphere passes through the field of view. The product of the cross-sectional capture area of the HLBC times its field of view is 1.7 meter2 steradian. Each picture covers the entire field of view and has a sensitive time of six milliseconds. The chamber is ex-
124504029
The search for quarks in terrestrial matter
Abstract Recent experimental searches for physical quarks stopped in terrestrial matter are reviewed and summarized.
115768104
CURRENT STATUS OF THE QUEST FOR QUARKS.
16729122
Wigner's Space-Time Symmetries Based on the Two-by-Two Matrices of the Damped Harmonic Oscillators and the Poincaré Sphere
The second-order differential equation for a damped harmonic oscillator can be converted to two coupled first-order equations, with two two-by-two matrices leading to the group Sp(2). It is shown that this oscillator system contains the essential features of Wigner’s little groups dictating the internal space-time symmetries of particles in the Lorentz-covariant world. The little groups are the subgroups of the Lorentz group whose transformations leave the four-momentum of a given particle invariant. It is shown that the damping modes of the oscillator correspond to the little groups for massive and imaginary-mass particles respectively. When the system makes the transition from the oscillation to damping mode, it corresponds to the little group for massless particles. Rotations around the momentum leave the four-momentum invariant. This degree of freedom extends the Sp(2) symmetry to that of SL(2, c) corresponding to the Lorentz group applicable to the four-dimensional Minkowski space. The Poincare sphere contains the SL(2, c) symmetry. In addition, it has a non-Lorentzian parameter allowing us to reduce the mass continuously to zero. It is thus possible to construct the little group for massless particles from that of the massive particle by reducing its mass to zero. Spin-1/2 particles and spin-1 particles are discussed in detail.
119304627
The evolution of FTK, a real-time tracker for hadron collider experiments
We describe the architecture evolution of the highly-parallel dedicated processor FTK, which is driven by the simulation of LHC events at high luminosity (1034 cm-2 s-1). FTK is able to provide precise on-line track reconstruction for future hadronic collider experiments. The processor, organized in a two-tiered pipelined architecture, execute very fast algorithms based on the use of a large bank of pre-stored patterns of trajectory points (first tier) in combination with full resolution track fitting to refine pattern recognition and to determine off-line quality track parameters. We describe here how the high luminosity simulation results have produced a new organization of the hardware inside the FTK processor core.
118905415
Group Contractions: Inonu, Wigner, and Einstein
Einstein's E = mc2 unifies the momentum-energy relation for massive and massless particles. According to Wigner, the internal space–time symmetries of massive and massless particles are isomorphic to O(3) and E(2) respectively. According to Inonu and Wigner, O(3) can be contracted to E(2) in the large-radius limit. It is noted that the O(3)-like little group for massive particles can be contracted to the E(2)-like little group for massless particles in the limit of large momentum and/or small mass. It is thus shown that transverse rotational degress of freedom for massive particles become contracted to gauge degrees of freedom for massless particles.
14420331
Harmonic Oscillators as Bridges between Theories: Einstein, Dirac, and Feynman
Other than scattering problems where perturbation theory is applicable, there are basically two ways to solve problems in physics. One is to reduce the problem to harmonic oscillators, and the other is to formulate the problem in terms of two-by-two matrices. If two oscillators are coupled, the problem combines both two-by-two matrices and harmonic oscillators. This method then becomes a powerful research tool to cover many different branches of physics. Indeed, the concept and methodology in one branch of physics can be translated into another through the common mathematical formalism. Coupled oscillators provide clear illustrative examples for some of the current issues in physics, including entanglement, decoherence, and Feynman's rest of the universe. In addition, it is noted that the present form of quantum mechanics is largely a physics of harmonic oscillators. Special relativity is the physics of the Lorentz group which can be represented by the group of by two-by-two matrices commonly called $SL(2,c)$. Thus the coupled harmonic oscillators can therefore play the role of combining quantum mechanics with special relativity. Both Paul A. M. Dirac and Richard P. Feynman were fond of harmonic oscillators, while they used different approaches to physical problems. Both were also keenly interested in making quantum mechanics compatible with special relativity. It is shown that the coupled harmonic oscillators can bridge these two different approaches to physics.
14332037
Mass and Spin Measurement with M(T2) and MAOS Momentum
We discuss the M T 2 -kink method to determine the masses of both the dark matter WIMP and its mother particle produced at the LHC. We then introduce a new kinematic variable, the M T 2 -Assisted-On-Shell (MAOS) momentum, that provides a systematic approximation to the invisible particle momenta in hadron collider events producing a pair of invisible particles, and apply it to certain SUSY processes and their UED equivalents to determine the spin of gluino/KK-gluon and of slepton/KK-lepton. An application of the MAOS momentum to the SM Higgs mass measurement is briefly discussed also.