Unusual High-Energy Phenomenology of Lorentz-Invariant Noncommutative Field Theories

It has been suggested that one may construct a Lorentz-invariant noncommutative field theory by extending the coordinate algebra to additional, fictitious coordinates that transform nontrivially under the Lorentz group. Integration over these coordinates in the action produces a four-dimensional effective theory with Lorentz invariance intact. Previous applications of this approach, in particular to a specific construction of noncommutative QED, have been studied only in a low-momentum approximation. Here we discuss Lorentz-invariant field theories in which the relevant physics can be studied without requiring an expansion in the inverse scale of noncommutativity. Qualitatively, we find that tree-level scattering cross sections are dramatically suppressed as the center-of-mass energy exceeds the scale of noncommutativity, that cross sections that are isotropic in the commutative limit can develop a pronounced angular dependence, and that nonrelativistic potentials (for example, the Coloumb potential) become nonsingular at the origin. We consider a number of processes in noncommutative QED that may be studied at a future linear collider. We also give an example of scattering via a four-fermion operator in which the noncommutative modifications of the interaction can unitarize the tree-level amplitude, without requiring any other new physics in the ultraviolet.Comment: 24 pages LaTeX, 4 eps figures (v2: reference added, v3: minor clarifications

Quarkonium Wave Functions at the Origin

We tabulate values of the radial Schr\"{o}dinger wave function or its first nonvanishing derivative at zero quark-antiquark separation, for $c\bar{c}$, $c\bar{b}$, and $b\bar{b}$ levels that lie below, or just above, flavor threshold. These quantities are essential inputs for evaluating production cross sections for quarkonium states.Comment: 9 pages, RevTeX, no figure

Gedanken Worlds without Higgs: QCD-Induced Electroweak Symmetry Breaking

To illuminate how electroweak symmetry breaking shapes the physical world, we investigate toy models in which no Higgs fields or other constructs are introduced to induce spontaneous symmetry breaking. Two models incorporate the standard SU(3)_c x SU(2)_L x U(1)_Y gauge symmetry and fermion content similar to that of the standard model. The first class--like the standard electroweak theory--contains no bare mass terms, so the spontaneous breaking of chiral symmetry within quantum chromodynamics is the only source of electroweak symmetry breaking. The second class adds bare fermion masses sufficiently small that QCD remains the dominant source of electroweak symmetry breaking and the model can serve as a well-behaved low-energy effective field theory to energies somewhat above the hadronic scale. A third class of models is based on the left-right--symmetric SU(3)_c x SU(2)_L x SU(2)_R x U(1)_{B-L} gauge group. In a fourth class of models, built on SU(4)_{PS} x SU(2)_L x SU(2)_R gauge symmetry, lepton number is treated as a fourth color. Many interesting characteristics of the models stem from the fact that the effective strength of the weak interactions is much closer to that of the residual strong interactions than in the real world. The Higgs-free models not only provide informative contrasts to the real world, but also lead us to consider intriguing issues in the application of field theory to the real world.Comment: 20 pages, no figures, uses RevTeX; typos correcte

Spacings of Quarkonium Levels with the Same Principal Quantum Number

The spacings between bound-state levels of the Schr\"odinger equation with the same principal quantum number $N$ but orbital angular momenta $\ell$ differing by unity are found to be nearly equal for a wide range of power potentials $V = \lambda r^\nu$, with $E_{N \ell} \approx F(\nu, N) - G(\nu,N) \ell$. Semiclassical approximations are in accord with this behavior. The result is applied to estimates of masses for quarkonium levels which have not yet been observed, including the 2P $c \bar c$ states and the 1D $b \bar b$ states.Comment: 20 pages, latex, 3 uuencoded figures submitted separately (process using psfig.sty

Prospects for the Bc Studies at LHCb

We discuss the motivations and perspectives for the studies of the mesons of the (bc) family at LHCb. The description of production and decays at LHC energies is given in details. The event yields, detection efficiencies, and background conditions for several Bc decay modes at LHCb are estimated.Comment: 20 pages, 5 eps-figure

Lepto-mesons, Leptoquarkonium and the QCD Potential

We consider bound states of heavy leptoquark-antiquark pairs (lepto-mesons) as well as leptoquark-antileptoquark pairs (leptoquarkonium). Unlike the situation for top quarks, leptoquarks (if they exist) may live long enough for these hadrons to form. We study the spectra and decay widths of these states in the context of a nonrelativistic potential model which matches the recently calculated two-loop QCD potential at short distances to a successful phenomenological quarkonium potential at intermediate distances. We also compute the expected number of events for these states at future colliders.Comment: 12 pages, 1 figure, 3 tables, plain TeX, requires harvmac. References updated and minor clarifications made. To appear in Physics Letters

Testing of Noodle Creek Site 41JS102 Jones County, Texas

Staff Archeologists from the Environmental Affairs Division of Texas Department of Transportation discovered buried cultural resources that constitute archeological site 41JS102, in June and July 2001 at the proposed location of a bridge replacement over Noodle Creek in Jones County, Texas. Shovel testing and backhoe trenching revealed cultural material at 65 cm below the surface. Following this discovery the Texas Department of Transportation made recommendations to the Texas Historical Commission to assess site 41JS 102 and they concurred. In September 2001 archeologists from the Texas Department of Transportation initiated the site assessment phase. Landowner complications halted that work before completion. Subsequently, TRC Environmental was provided a Work Authorization under an existing general services contract to complete the assessment of 41JS102 in December 2001. The fieldwork consisted of the hand excavation and documentation of eight 1 by 1 m test units and the digging and documenting of six backhoe trenches. Limited and scattered historic artifacts were recovered from the upper parts of the two alluvial terraces (T0 and T1). A prehistoric component with quantities of lithic debitage and sparse burned rocks, limited stone tools and mussel shells, and one possible cultural feature were encountered in a sloping, but well defined 10 to 15 cm thick zone in the T1 deposits. The Principal Investigator recommended prehistoric site 4 1JS102 was eligible for inclusion in the National Register of Historic Places and as a State Archeological Landmark. However, the staff at Texas Department of Transportation disagreed with that recommendation and presented an opposing case to the Texas Historical Commission who concurred with the Texas Department of Transportation\u27s recommendations. Consequently, no further archeological investigations will occur prior to the proposed development

Eligibility Assessment of the Slippery Slope Site (41MS69) in TxDOT Right-of-Way in Mason County, Texas

A private landowner reported archeolgical materials were looted along a steep road cut on the southwestern side of Farm to Market (FM) road 1871 along the Llano River south of Mason, Texas (CSJ: 1111-04-002). The landowner was concerned that looting had undermined massive oak trees enough that they might fall directly onto the roadway below. The looting was occurring within Texas Department of Transportation (TxDOT) right-of-way and east of the existing fence line. In June 2004, archeologists from the Planning, Permitting and Licensing Practice of TRC Environmental Corporation (TRC) Austin office conducted a site specific recording, geoarcheological investigation, and archeological testing for National Register of Historic Places (NRHP) and State Antiquities Landmark (SAL) eligibility assessment at prehistoric site 41MS69, the Slippery Slope site. This cultural resource investigation was conducted for the Environmental Affairs Division of TxDOT through multiple Scientific Services Contracts, Work Authorizations, and Supplemental Work Authorizations over the years and through Texas Antiquities Permit No. 3447, issued by the Texas Historical Commission to Principal Investigator, J. Michael Quigg

Root-Be-Gone (41YN452): Data Recovery of Late Archaic Components in Young County, Texas Vol I

This cultural resource investigation was necessitated by the proposed bridge replacement and new right-of-way and easement along the Farm to Market road at Gages Creek crossing (CSJ: 3149-02-010) by the Texas Department of Transportation (TxDOT) in southern Young County. From January 29, 2007 through March 16, 2007, an archeological crew from the Cultural Resources Department of TRC Environmental Corporation’s (TRC’s) Austin office conducted data recovery excavations in part of site 41YN452 (RootBe-Gone) before any disturbance from the planned bridge replacement activities occurred. This data recovery program was conducted under TxDOT Scientific Services Contract No. 575XX SA008 and Texas Antiquities Permit No. 4003. Data recovery investigations were conducted along the western side of the existing two-lane paved road in two areas previously documented to have high concentrations of cultural activities centered on cultural features. These two areas were identified during TRC’s 2006 site eligibility assessment, which was also conducted on adjacent site 41YN450. Only the Root-Be-Gone site was accepted as eligible for listing on the National Register of Historic Places and, therefore, subject to intensive data recovery investigations. This report provides the accepted research design that guided the analyses, describes the methods employed, discusses the excavation process, and presents detailed findings and results of technical analyses from the 50.5 m3 (144 m2) data recovery excavations for three, horizontally-separated Late and Terminal Archaic components at Root-Be-Gone. The data recovery investigations included the mechanical removal of roughly 30 to 60 cm of sediment from above a previously identified target zone, cultural materials in a buried A horizon that contained an apparent Terminal Archaic assemblage in two horizontally-separated areas. Each area was targeted by a single block excavation, labeled North and South Block, which are roughly 70 m apart and which parallel the existing right-of-way. Following the mechanical stripping to access the targeted Terminal Archaic component in the buried A horizon, hand-excavations were conducted in 1-by-1 m units in continuous blocks through the targeted buried A horizon. The target zone varied from 20 to 40 cm thick. This buried A horizon appeared to contain a single, isolated Terminal Archaic component. Root-Be-Gone (41YN452) yielded what is considered three horizontally-separate cultural components (labeled 1, 2, and 3) in the buried A horizon. This buried A horizon varied in depth from 45 to 70 cmbs. A few scattered Late Prehistoric arrow points were discovered on the surface and above the Terminal Archaic component. The younger and scattered Late Prehistoric artifacts were determined to occur above or on top of the buried A horizon. No definable cultural features were identified with the scattered arrow points. These scattered, Late Prehistoric materials were deemed insignificant and not targeted during the data recovery investigations. The excavations yielded assemblages of chipped stone tools (N = 154), lithic debitage (N = 1,486), mussel shell (N = 8,430), faunal bone (N = 71), charcoal (N = 111), burned rocks (N = 4,421), features (N = 18), and other cultural materials, including sediment samples. During the analyses, wood charcoal radiocarbon results from across the excavated areas revealed that a minimum of two, and possibly three different Terminal and/or Late Archaic components were represented in the buried A horizon in the two blocks. The North Block was radiocarbon dated by nine accepted dates to ca. a 230 year period between 1100 and 1330 B.P. The cultural materials recovered were assigned to a single, well-defined and isolated Terminal Archaic Component 1. That component yielded three dart points and one tiny arrow point associated with 14 cultural features. The features were comprised mostly of quantities of freshwater mussel shell concentrations in dumps, most associated with small scattered burned rocks; a burned, rock-filled heating element, scattered mussel shells and lithic debitage, and a few scattered formal chipped stone tools. The absolute age documented for this Terminal Archaic component that yielded dart points overlaps in time with the Scallorn arrow point using populations of the Austin phase of the Late Prehistoric period. The South Block yielded minimally two sets of radiocarbon dates. The northern two-thirds of the South Block yielded seven accepted absolute wood charcoal dates that range over a nearly 630 year period between 690 and 1320 B.P. The targeted buried A horizon yielded what appeared as a single Terminal Archaic dart point and a limited stone tool assemblage. This assemblage is assigned to the Late Archaic Component 2. TxDOT archeologists considered this part of the South Block to be potentially mixed based on the wood charcoal radiocarbon dates obtained. Therefore, TxDOT archeologists decided that detailed analyses were restricted to the two cultural features (Features 11 and 13) and the formal stone tool assemblage recovered from that area. Because of the possible mixed cultural materials, this data was not used to address the presented research questions. The southern one-third of the South Block was radiocarbon dated by four accepted wood charcoal dates to a narrow 120 year period with an average age of 1855 B.P. This area was dominated by a single 3.0 to 3.5 m diameter mussel shell feature (Feature 4) that lacked associated formal chipped stone tools and diagnostic dart points. Here, this material is assigned to the Late Archaic Component 3. Because of the documented age difference from the Terminal Archaic Component 1 in the North Block, this material was not used to address the research questions that focused on the Terminal Archaic period. Six research questions were targeted and address issues that include: whether the excavations yielded an isolatable Terminal Archaic component, what cultural materials were associated with the Terminal Archaic component, how this assemblage compares to other Terminal Archaic assemblages in the region, what was the subsistence base and broader economic pattern for this period, and was the bow and arrow adopted simultaneously by all groups. Following the acceptance of the final report, these materials were permanently curated at the Texas Archeological Research Laboratory (TARL) in Austin. The Texas Historical Commission granted permission to curate only a small sample of the freshwater mussel shells collected during these investigations. The curated shells originate mostly from identified cultural features in all three components