Superconducting Super Collider Research Articles

Strong W+W+ scattering signals at pp supercolliders.

Like-sign W-boson production has been proposed as a probe of possible strong scattering in the electroweak-symmetry-breaking sector that would enhance the production of longitudinally polarized gauge bosons. We evaluate the expected signals in the channel pp\ensuremath{\rightarrow}${\mathit{W}}^{+}$${\mathit{W}}^{+}$X, ${\mathit{W}}^{+}$\ensuremath{\rightarrow}${\mathit{l}}^{+}$\ensuremath{\nu} at pp supercolliders, for several different theoretical models in which strong scattering occurs, using realistic acceptance cuts and comparing with standard-model background contributions. We find that backgrounds are potentially a serious problem, especially those from electroweak production of transversely polarized W bosons. However, vetoing events with high-${\mathit{p}}_{\mathit{T}}$ jets in the central region makes it possible to suppress all backgrounds at little cost to the signal. With an integrated luminosity of 10 ${\mathrm{fb}}^{\mathrm{\ensuremath{-}}1}$ at the Superconducting Super Collider (SSC) or 100 ${\mathrm{fb}}^{\mathrm{\ensuremath{-}}1}$ at the CERN Large Hadron Collider (LHC) and a dilepton detection efficiency of 50%, there could be 3--8 signal events, depending on the model, with about 3.5 (1.7) background events at the SSC and 8.5 (2.5) background events at the LHC for ${\mathit{m}}_{\mathit{t}}$=100 (200) GeV.

Production of neutral technicolor pseudo Goldstone bosons and QCD background at the Superconducting Super Collider.

The production of the neutral technicolor pseudo Goldstone bosons ${\mathrm{P}}^{0\ensuremath{'}}$ and ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ at large transverse momentum in pp\ifmmode\bar\else\textasciimacron\fi{} collisions, pp\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}g(q)${\mathrm{P}}^{0\ensuremath{'}}$(${\mathrm{P}}_{8}^{0\ensuremath{'}}$)X, has been investigated at the Superconducting Super Collider (SSC) energy. The major two-body and three-body decay modes in tree diagrams are also investigated in detail. The tt\ifmmode\bar\else\textasciimacron\fi{} decay channel would dominate the decays of both ${\mathrm{P}}^{0\ensuremath{'}}$ and ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ if it is allowed. Otherwise, gg and 3g will be the dominant decay modes unless the mass of the ${\mathrm{P}}^{0\ensuremath{'}}$ and ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ are below 40 GeV, where bb\ifmmode\bar\else\textasciimacron\fi{} becomes dominant. The tt\ifmmode\bar\else\textasciimacron\fi{} channel will be the ideal signal for detecting these bosons since the signal is much larger than the QCD background. However, in the absence of the tt\ifmmode\bar\else\textasciimacron\fi{} channel, the \ensuremath{\tau}\ensuremath{\tau}\ifmmode\bar\else\textasciimacron\fi{} mode can be used to identify ${\mathrm{P}}^{0\ensuremath{'}}$ up to ${\mathrm{m}}_{\mathrm{P}}$=300 GeV in the transverse-momentum range ${\mathrm{P}}_{\mathrm{\ensuremath{\perp}}}$\ensuremath{\lesssim}100 GeV. Similarly, the bb\ifmmode\bar\else\textasciimacron\fi{} decay mode can serve as a useful signal for the identification of ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ up to ${\mathrm{m}}_{\mathrm{P}}$=300 GeV for ${\mathrm{P}}_{\mathrm{\ensuremath{\perp}}}$ between 500 and 700 GeV. Our results show that these high-transverse-momentum production processes are useful in searching for the ${\mathrm{P}}^{0\ensuremath{'}}$ and ${\mathrm{P}}_{8}^{0\ensuremath{'}}$ at the SSC.

Production of right-handed gauge bosons and heavy Majorana neutrinos at the Superconducting Super Collider.

The processes {ital p}+{ital p}{r arrow}2{ital l}{sup {plus minus}}+{ital X}, {ital p}+{ital p}{r arrow}{ital W}{sub {ital R}}{r arrow}{ital N}+{ital l}+{ital X}, and {ital p}+{ital p}{r arrow}{ital Z}{sub {ital R}}{r arrow}2{ital N}+{ital l}+{ital X} (where {ital N} is a heavy Majorana neutrino) are discussed and estimated at the energy scale of the Superconducting Super Collider (SSC). These reactions may serve as the indications of right-handed gauge bosons and heavy Majorana neutrinos that propagate in the intermediate state or are produced directly. The observation of same-sign charged-lepton pairs in final states is a possible clean signal for production of {ital W}{sub {ital R}}, {ital Z}{sub {ital R}}, and the heavy Majorana neutrino {ital N}. A detailed calculation shows that with suitable cuts the background can be overwhelmed by the signals for a wide range of right-handed gauge-boson and heavy-neutrino masses (from hundreds GeV to several TeV), and this signal is observable at the SSC. With the completion of the SSC, such experiments could be carried out.

The role of multiplier bounds in efficiency analysis with application to Kansas farming

As long recognized, the problem of efficiency involves both technical and economic facets. Determination of the technically efficient firms provides the base for economic analysis. Values in terms of prices or costs must be introduced into the problem to work towards finding firms which might be regarded as overall efficient. That problem came to the forefront in a 1984 study to find the best site for location of a Superconducting Super Collider (SSC) in the state of Texas. Application of a modern value-free frontier method called Data Envelopment Analysis (DEA) to the data, which was primarily engineering and geological in character, showed five of the six feasible sites were technically efficient. However, additional socioeconomic/environmental data provided ‘price-cost’ inequality bounds for the mathematical multipliers in the DEA problem. Including those bounds in the analysis, which was called an Assurance Region (AR), reduced the number of efficient sites from five to one. In 1988, the U.S. Department of Energy in national competitionactually selected the site identified by the bounding method for location of the SSC. In this paper, the AR concept is defined for efficiency analysis of the linear production possibility set. As applied here to 83 farms, we use only the special case of AR consisting of separate linear homogeneous restrictions on the input and output multipliers. When applied to the technically efficient farms, the AR principles reduced the number of candidates for overall efficiency from 23 to 8 in one case (Ratio Model) and from 44 to 13 in another case (Convex Model).

Excited-quark and -lepton production at hadron colliders.

The existence of excited states is a natural consequence of composite models for quarks and leptons. Production rates and signatures are discussed for hadron colliders presently operating (CERN Super $p\overline{p}$ Synchrotron and Fermilab Tevatron) or under study (CERN Large Hadron Collider and Superconducting Super Collider). Contact interactions may be an important source for excited fermions and could influence the signatures of such particles significantly. Excited quarks could be discovered with masses up to about ⅓-\textonehalf{} of the total collider energy while excited leptons could be accessible up to ⅕-⅓ of the available energy. Large lepton yields are expected if quarks and leptons share common subconstituents.

A genuine global partnership?

Japan is considering a huge financial investment in the US Superconducting Super Collider. But other types of contribution, to this and any international project, are equally important.

The SSC: Status and physics update

I give a very brief update on the current organizational and budgetary status of the Superconducting Super Collider (SSC) and review the most recent refinements and new approaches for finding several important physics signals.

Measurement of proton induced radiation damage to CMOS transistors and p-i-n diodes

As part of a program to develop a silicon tracking device for the Superconducting Super Collider (SSC), radiation-hard CMOS transistors and p-i-n diodes have been exposed to the 800-MeV LAMPF (Los Alamos Meson Physics Facility) proton beam. The fluences accumulated in one week corresponded to the expected radiation levels of about ten SSC years. The leakage current constants for p-i-n diodes and threshold voltage shifts for CMOS transistors are determined under different biasing conditions. The results are presented and examined in detail. >

Photon‐stimulated desorption yields from stainless steel and copper‐plated beam tubes with various pretreatments

Photon‐stimulated desorption (PSD) from the walls of electron storage rings and associated beamlines imposes serious limits on their beam quality and beam lifetimes. Stainless steel (SS) is the most used material for beam lines and its use has become more dominant for dedicated light sources. Copper‐plated SS beam pipes have been selected for the superconducting super collider (SSC) project. Three‐meter‐long tubes of 3, 8.8, and 10 cm diameter were prepared using the following pretreatments common in storage rings. The samples were chemically cleaned only, vacuum baked to 200 °C, vacuum fired to 950 °C, and argon–oxygen glow‐discharge conditioned. A dedicated beam line at the National Synchrotron Light Source was used to measure PSD from the samples. Desorption was measured as a function of beam current during exposure to white light having a critical energy of 500 MeV. Our results are presented and compared with PSD from previous work on aluminum and SS here and at other laboratories. Glow‐discharged SS ...

Computer automated data acquisition and control for measurement of scintillation materials and scintillating fibers

Scintillation materials and scintillating fibers being developed for potential use as tracking detectors at the SCC (Superconducting Super Collider) are discussed. These fibers will need high scintillation efficiency, short decay time constants, and good transmission characteristics. The authors discuss the combined use of the Apple Macintosh family of microcomputers and custom-built and commercially available hardware and software used at Notre Dame to aid in determining suitable materials and production characteristics for long scintillating fibers or capillaries. This system includes the use of a Hitachi model F-2000 Fluorescence Spectrophotometer, LeCroy 3001 qVt multichannel analyzer, LeCroy 8901A CAMAC to GPIB (General Purpose Interface Bus) interface, LeCroy 4604 scaler, and a Centent CN0170 microstepping motor controller. The software for the system, written primarily in Microsoft QuickBASIC, is discussed in detail. The potential use of a DigiKrom 240 monochromater for understanding attenuation as a function of wavelength and for reflection coefficient measurements is also discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Studies in the radiation resistance of plastic scintillators: review and prospects

With the planned construction of high-luminosity hadron colliders, the SSC (Superconducting Supercollider) and LHC (Large Hadron Collider), the issue of radiation resistance of detector components has arisen as a priority item. The radiation resistance of organic scintillators is discussed, with the dual goals of presenting a review of the problem and pointing the way to possible solutions. It is concluded that progress in producing sufficiently radiation-hard organic scintillators has been significant, but there remain many important details to be investigated. It is feasible that an organic scintillator may be produced within the next few years with a performance specification of 100 Mrad. >

Effects of radiation damage to ionization chamber liquids

Because of the high levels of radiation that will exist in the detector areas of the SSC (Superconducting Supercollider), it is important to understand how radiation affects calorimetry liquids. The results for tetramethylsilane, tetramethylgermanium, and tetramethylpentane as well as for methane-argon solutions are discussed. Tests have shown significant pressure buildup due to H/sub 2/ and CH/sub 4/. There is a loss of charge collection efficiency at large radiation doses. Radiation products can change the drift velocity of electrons and the free ion yield.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Beam extraction from TeV accelerators using channeling in bent crystals

Bent crystal channeling offers an interesting alternative for beam extraction from trans-GeV accelerators. Conventional extraction employs resonant beam blow-up coupled with electromagnetic beam deflecting channels. It is limited by the length of the available accelerator straight section. Channeling crystals require much less space. A five-step approach to applying crystal extraction in the Superconducting Super Collider (SSC) is discussed. Two steps, extraction from the 8 GeV Dubna Synchrophasotron and the 76 GeV Serpukhov accelerator, have occurred. The next possibility is extraction from a multi-hundred GeV superconducting accelerator. In the nineties the program could continue at UNK (3 TeV) and culminate at the 20 TeV SSC. The possibilities and limitations of crystal extraction are reviewed. More information is needed on dechanneling in bent crystals including the effects of dislocations at TeV energies. Long, “dislocation-free” crystals are required. A more thorough understanding of the theory of crystal extraction is also desirable.

SU(15) grand unification.

A grand unified model based on SU(15) is described. Baryon-numbe-violating processes such as proton decay are absent in both the gauge and Higgs sectors. A number of new gauge bosons are predicted at Superconducting Super Collider energy, including doubly charged gauge bosons coupling only to leptons.

NIH Conflict-of-Interest Guidelines

In the News & Comment article "Super Collider advocates tangle with cost cutters" by Mark Crawford (12 Jan., p. 152), the collision energy of the Superconducting Super Collider (SSC) was incorrectly described as being two orders of magnitude greater than that of the Tevatron. The SSC's collision energy is supposed to be 40 trillion election volts-20 times that of the Tevatron. In addition, the $7.2-billion cost estimate for the project is based on inflated dollars, not constant dollars, as was stated.

Tolerance of imperfections in high-energy circular accelerators for polarized protons.

Realistic calculations show that imperfection-spin-resonance strengths {epsilon}{sub imp} can be corrected to {epsilon}{sub imp}{lt}1, at 20 TeV, Superconducting Super Collider (SSC) energy. Statistical analysis agrees well with the numerical calculation. The polarized proton must be accelerated through overlapping intrinsic and imperfection resonances. We found a correlation between the tolerable strengths of intrinsic and imperfection resonances {epsilon}{sub int} and {epsilon}{sub imp}, that is, at smaller {epsilon}{sub int}, the tolerable {epsilon}{sub imp} becomes larger, and vice versa. To obtain a larger tolerable {epsilon}{sub imp}, we suggest that the number of snakes should be chosen according to {ital N}{sub {ital S}}{ge}5{epsilon}{sub int}. When a large number of snakes is used in the accelerator, the tolerable deviation of the spin rotational angle from 180{degree} for each snake becomes more stringent. The error in the spin rotation angle gives rise to (1) an equivalent picket-fence imperfection resonance {epsilon}{sub imp}{sup eq} and (2) an energy-dependent spin tune {nu}{sub {ital s}}. Both of these effects may cause depolarization. Further, when the snake axis is not properly arranged, the spin tune deviates from half-integer. In this case, depolarization may arise from the snake resonances. Our analysis indicates that acceleration of polarized protons in the SSC is technically feasiblemore » if care is taken in constructing the snakes.« less

New method to detect a heavy top quark at the Fermilab Tevatron.

We present a new method to detect a heavy top quark with mass \ensuremath{\sim} 180 GeV at the upgraded Fermilab Tevatron ($\sqrt{S}=2$ TeV and integrated luminosity 100 ${\mathrm{pb}}^{\ensuremath{-}1}$) and the Superconducting Super Collider (SSC) via the $W$-gluon fusion process. We show that an almost perfect efficiency for the "kinematic $b$ tagging" can be achieved due to the characteristic features of the transverse momentum ${P}_{T}$ and rapidity $Y$ distributions of the spectator quark which emitted the virtual $W$. Hence, we can reconstruct the invariant mass ${M}^{e\ensuremath{\nu}b}$ and see a sharp peak within a 5-GeV-wide bin of the ${M}^{e\ensuremath{\nu}b}$ distribution. We conclude that more than one year of running is needed to detect a 180-GeV top quark at the upgraded Tevatron via the $W$-gluon fusion process. Its detection becomes easier at the SSC due to a larger event rate.

A determination of the shear strength parameters of a fine-grained cemented alluvium in the US Desert Southwest

Abstract Laboratory determination of shear strength parameters for alluvial soils in the US Desert Southwest is imprecise at best. These soils contain varying amounts of carbonate cementation and it is extremely difficult to acquire undisturbed samples using conventional soil sampling techniques. Furthermore, even when samples can be retrieved, they are usually not representative of the in situ soil which can demonstrate a wide range of cementation. Therefore, the results of laboratory strength testing may not be representative of the actual in situ behaviour. For these reasons, a simple field test is developed which may be used in conjunction with conventional laboratory testing and analytical procedures to estimate the in situ strength properties of such alluvial deposits. The in situ testing involves a series of plate load tests performed at the crest of freshly cut slopes. A steel plate of known dimensions is loaded by an 89 kN (10 tons) hydraulic jack until the slope fails. The counter weight of a power shovel is used as a reaction support. The failure load and slip surface geometry are measured and recorded. A two-dimensional slope stability procedure (Bishop’s Modified Method) is used to back calculate the value of cohesion associated with failure of the field slopes. The analytical procedure developed by Hovland is used to account for the three-dimensional ‘end effects’ present in the field load tests and to correct the value of cohesion obtained from the Bishop solution. The values of c and φ obtained in this way are used to evaluate the stability of the trench slopes at the State of Arizona’s site for the US Department of Energy’s proposed Superconducting Super Collider (SSC) Project. The determination of a realistic factor of safety during construction is critical to the economical use of open-cut construction techniques for approximately 50 per cent of the 83.7 km (52 miles) circumference of the proposed SSC ring.

Double Pomeron Exchange from the ISR to the SSC

After a general introduction to Double Pomeron Exchange I show how the existence of the process was demonstrated at the CERN Intersecting Storage Rings and discuss its value there as a spectroscopic tool in meson/glueball studies. At higher collision energies as now available at the Super Proton Synchrotron and Fermilab p p Colliders it would be very interesting to study hard processes in Double Pomeron Exchange and investigate Pomeron structure. The still higher Large Hadron Collider and Superconducting Super Collider energies extend the range of this physics dramatically, possibly into the electroweak sector.

: Social Assessment of High Technology: The Superconducting Super Collider in Southeast Michigan . Richard W. Stoffle, Michael W. Traugott, Florence Jensen, Robert Copeland. ; The Superconducting Super Collider at the Stockbridge, Michigan, Site: Community Support and Land Acquisition . Richard W. Stoffle, Michael W. Traugott, Camilla L. Harshbarger, Florence V. Jensen, Michael J. Evans, Paula Drury.

Book reviewed in this article: Social Assessment of High Technology: The Superconducting Super Collider in Southeast Michigan. Richard W. Stoffle, Michael W. Traugott, Florence Jensen, and Robert Copeland The Superconducting Super Collider at the Stockbridge, Michigan, Site: Community Support and Land Acquisition. Richard W. Stoffle, Michael W. Traugott, Camilla L. Harshbarger, Florence V. Jensen, Michael J. Evans, and Paula Drury