03.06.2013 Views

N=2 Supersymmetric Gauge Theories with Nonpolynomial Interactions

N=2 Supersymmetric Gauge Theories with Nonpolynomial Interactions

N=2 Supersymmetric Gauge Theories with Nonpolynomial Interactions

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

2.3. The Ansatz 27<br />

2.3 The Ansatz<br />

In this section we confine our investigation to couplings of the vector-tensor multiplet<br />

to just one abelian vector multiplet that gauges the central charge, which is our main<br />

objective. To this end we make an Ansatz for the constraints on L and apply the<br />

consistency conditions (C.1–3), i.e. those that do not contain spacetime derivatives.<br />

Since the only fields in the multiplets under consideration that transform nontrivially<br />

under the automorphism group SU(2) are given by D i αL, D i αZ, D i D j Z and their complex<br />

conjugates, the most general Ansatz compatible <strong>with</strong> the properties (2.23) reads<br />

α ¯ D j)<br />

˙α L = a D(i αZ ¯ D j)<br />

˙α L − ā ¯ D (i<br />

˙α ¯ Z D j)<br />

α L + b D (i<br />

αZ ¯ D j)<br />

˙α ¯ Z + c D (i<br />

αL ¯ D j)<br />

˙α L (2.40)<br />

D (i<br />

D (i D j) L = A D (i Z D j) L + B ¯ D (i ¯ Z ¯ D j) L + C D i D j Z + D D i Z D j Z<br />

+ E ¯ D i ¯ Z ¯ D j ¯ Z + F D i L D j L + G ¯ D i L ¯ D j L .<br />

(2.41)<br />

Here the coefficients are arbitrary local functions of the superfields L, Z and ¯ Z. ā is<br />

the complex conjugate of a, and b and c must be real. Recall that since Z is an abelian<br />

vector superfield, it satisfies<br />

D i D j Z = D (i D j) Z = ¯ D i ¯ D j ¯ Z , D i α ¯ Z = 0 = ¯ D i ˙αZ . (2.42)<br />

The first consistency condition (C.1), now written as a proper superfield equation,<br />

requires<br />

D (i<br />

αD j D k) L = 0 , (2.43)<br />

which simply expresses the fact that the spinor derivatives D i α anticommute when<br />

symmetrized in the SU(2) indices,<br />

D (i<br />

αD j D k) = −ε γβ D (j<br />

β Di αD k)<br />

γ = − 1<br />

2 εγβ εαγD (j<br />

β Di D k) = − 1<br />

2 D(i<br />

αD j D k) = 0 . (2.44)<br />

When the Ansatz (2.41) is inserted, condition (2.43) translates into a set of nonlinear<br />

partial differential equations for the coefficient functions. Differentiations <strong>with</strong> respect<br />

to L and Z arise from the action of D i α on the coefficients 4 , while quadratic terms<br />

appear because we have to use the constraints (2.40), (2.41) when the spinor derivative<br />

acts on D i αL or ¯ D i ˙αL. Introducing the abbreviations<br />

∂ ≡ ∂<br />

∂Z , ∂¯ ∂<br />

≡<br />

∂ ¯ Z , ∂L ≡ ∂<br />

, (2.45)<br />

∂L<br />

we have for instance<br />

D (i<br />

j k) (i<br />

α F D L D L = ∂F D αZ + ∂LF D (i<br />

αL D j L D k) L − 2F D β(i L D j αD k)<br />

β L<br />

= ∂F D (i<br />

αZ D j L D k) L − F D (i<br />

αL D j D k) L ,<br />

where the expression proportional to ∂LF vanishes by the same reasoning as for eq.<br />

(2.44). In this way condition (2.43) decomposes into ten linearly independent terms<br />

whose coefficients must vanish separately,<br />

1) 0 = ∂F − 1<br />

2 ∂LA<br />

4 There is no differentiation <strong>with</strong> respect to ¯ Z since it is antichiral.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!