SLIDE 9 The differential cross-section for spin averaged collisions producing a photon and 2 X particles with summed over polarizations and the X species, i=1,2,…,N = # of extra dimensions
( ) ( )
( )
{
( ) (
)
( ) }
2 2 2 2 2 2 2 8 3 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 2 2 2
4 1 1 ˆ 2 ˆ 4 15,360 ˆ 4 20 2 ˆ 4 8 4
XX X X X X X X X
d k M N sk u t dk dt F s ut k sk ut M k M K k K k M S k M M M s k
γ
σ α π π τ − ⎡ ⎤ ⎡ ⎤ = + + × ⎢ ⎥ ⎣ ⎦ ⎣ ⎦ × + ⎡ ⎤ − ⎣ + + ⎡ ⎤ ⎡ ⎤ + + − ⎣ ⎦ ⎢ ⎣ ⎦ ⎥ ⎦
q q −
2 2 2 2 2 1 2 1 1 1 2 2 2 2 1
with the antiquark and quark momenta, the photon momenta and the brane vector momenta. , , The Mandelstam variables , , and ˆ ( ) . Neglecting the quark ( ) ( ) ( ) mas s p p t p q u p q p p q k k k k k = + = − = − = +
( )
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
ses implies . The Standard Model coupling and propagator factor cos 1 1 1 1 1 (sin ) 2cos sin . ( ) ( ) c ˆ
16 4 4
Z W W W W Z Z Z W
k M SM k k M s t u k M k θ πα θ θ θ θ ⎡ ⎤ ⎛ ⎞ − ⎛ ⎞⎛ ⎞ ⎛ ⎞ ⎢ ⎥ ⎜ ⎟ ≡ + + − + − ⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟ − + Γ ⎢ ⎥ ⎝ ⎠ ⎝ + + = ⎠ ⎝ ⎠ ⎝ ⎠ ⎣ ⎦
No Interference—Energy-Momentum Tensor and Extrinsic Curvature Terms Add