Constraint on the branching ratio of B_c \to tau nu from LEP1 and consequences for R(D(*)) anomaly

Recently there has been interest in the correlation between R(D*) and the branching ratio (BR) of $B_c \to \tau \nu$ in models with a charged scalar H^\pm. Any enhancement of R(D*) by $H^\pm$ alone (in order to agree with current data) also enhances $BR(B_c \to \tau \nu$), for which there has been no direct search at hadron colliders. We show that LEP data taken at the Z peak requires BR($B_c \to \tau \nu$) < 10%, and this constraint is significantly stronger than the recent constraint BR($B_c \to \tau \nu$) < 30% from considering the lifetime of B_c. In order to respect this new constraint, any explanation of the R(D) and R(D*) anomaly in terms of $H^\pm$ alone would require the future measurements of R(D*) to be even closer to the Standard Model prediction. A stronger limit on BR($B_c \to \tau \nu$) (or its first measurement) would be obtained if the L3 collaboration used all its data taken at the Z peak.Comment: 14 pages, 4 figures, a reference and two sentences adde

Complete CKM quark mixing via dimensional deconstruction

It is shown that the deconstruction of $[SU(2)\times U(1)]^N$ into $[SU(2)\times U(1)]$ is capable of providing all necessary ingredients to completely impliment the complex CKM mixing of quark flavors. The hierarchical structure of quark masses originates from the difference in the deconstructed chiral zero-mode distribution in theory space, while the CP-violating phase comes from the genuinely complex vacuum expectation value of link fields. The mixing is constructed in a specific model to satisfy experimental bounds on quarks' masses and CP violation.Comment: RevTex4, 25 pages, typos in section IIC corrected, published versio

TTL implementation of a CAMB tree network switch

Packet collisions and their resolution create a performance bottleneck in random-access LANs. A hardware solution to this problem is to use a collision avoidance switch. These switches allow the implementation of random access protocols without the penalty of collisions among packets. An architecture based on collision avoidance is the CAMB (Collision Avoidance Multiple Broadcast) Tree network, where concurrent broadcasts are possible.The purpose of this paper is to present two implementations for a CAMB Tree switch. First, a general outline of the CAMB switch is provided. Then, a description of the two implementations is given