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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Towards the Standard Model on Rigid D-Branes - Hon
ecker\, MG (Johannes Gutenberg-Universitt Mainz)
DTSTART;TZID=Europe/London:20120628T161500
DTEND;TZID=Europe/London:20120628T163000
UID:TALK38725AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/38725
DESCRIPTION:D-brane worlds have provided a geometrically intui
tive approach for Standard Model (SM) engineering
within string theory compactifications. While the
types and ranks of gauge groups and the chiral mat
ter content are tackled in a straightforward manne
r\, it remains on the one hand an open question if
the SM can be obtained on rigid D-branes - withou
t continuous gauge symmetry breaking along flat di
rections and with non-trivial D-brane instanton co
ntributions to the effective action - and on the o
ther hand if such models are consistent with low-e
nergy data. The T6/Z(2)xZ(6') orbifold with discre
te torsion admits a plethora of left-right symmetr
ic `local models' without exotic matter in the adj
oint\, symmetric or antisymmetric representation.
However\, `global' completions usually come at the
cost of introducing new exotic states in bifundam
ental representations. It furthermore turns out th
at USp(2) and SO(2) in place of U(2) symmetries ca
n at most provide one particle generation. Last bu
t not least\, it turns out that for any T6/Z(2)xZ(
2M) orbifold with discrete torsion and tilted tori
\, orientifold invariant stacks of D6-branes carry
USp(2N) or SO(2N) gauge groups depending on their
relative position to the exotic O6-plane. The new
classification reduces the number of K-theory con
straints. If time permits\, I will briefly comment
on the drastic change in the pattern of Yukawa co
uplings on orbifolds compared to the six-torus usi
ng a T6/Z6' example. As a result\, quark Yukawas c
an provide large mixings while lepton Yukawas are
flavour diagonal at leading order. Also the rule o
f `one massive generation only' is circumvented.\n
\n
LOCATION:Seminar Room 2\, Newton Institute Gatehouse
CONTACT:Mustapha Amrani
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