PHYS08200604018 Shamik Banerjee - Homi Bhabha National ...
PHYS08200604018 Shamik Banerjee - Homi Bhabha National ...
PHYS08200604018 Shamik Banerjee - Homi Bhabha National ...
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4.5. EXAMPLES 65<br />
Finally we turn to the constraint from black hole entropy. As in §4.5.1, in this case we<br />
have g(τ) = η(τ) 24 in (4.4.4). Thus (4.4.6) takes the form<br />
̂Φ(ˇρ, ˇσ, ˇv) ∝ (2v − ρ − σ) 10 {v 2 η(ρ) 24 η(σ) 24 + O(v 4 )} , (4.5.3.25)<br />
where (ρ, σ, v) and (ˇρ, ˇσ, ˇv) are related via (4.4.7).<br />
Before concluding this section we would like to note that we can easily extend the analysis<br />
of this section to the complementary subset of torsion 2 dyons with Q, P primitive and Q 2 /2<br />
and P 2 /2 odd. For this we consider six dimensional electric and magnetic charge vectors with<br />
metric<br />
⎛<br />
⎞<br />
0 1 0 0<br />
L = ⎜ 1 0 0 0<br />
⎟<br />
⎝ 0 0 0 I 2<br />
⎠ , (4.5.3.26)<br />
0 0 I 2 0<br />
and take the set A to be the collection of charge vectors (Q, P ) with<br />
⎛ ⎞ ⎛ ⎞<br />
1<br />
1<br />
−1<br />
1<br />
1 ⎟ ⎜ ⎟<br />
This has<br />
Q =<br />
⎜<br />
⎝<br />
2m + 1<br />
1<br />
1<br />
Q 2<br />
2 = 2m + 1, P 2<br />
2<br />
, P =<br />
⎟ ⎜<br />
⎠ ⎝<br />
2K + 1<br />
2J + 1<br />
1<br />
−1<br />
, m, K, J ∈ Z . (4.5.3.27)<br />
⎟<br />
⎠<br />
= 2(K − J) + 1, Q · P = 2(K + J − m + 1) . (4.5.3.28)<br />
Thus we have Q 2 /2 and P 2 /2 odd and Q · P even. Furthermore we still have the constraint<br />
that Q 2 + P 2 + 2Q · P is a multiple of 8. Thus with (ˇρ s , ˇσ s , ˇv s ) defined as in (4.5.3.3), the<br />
partition function is antiperiodic under (ˇρ s , ˇσ s , ˇv s ) → (ˇρ s +2, ˇv s , ˇσ s ), (ˇρ s , ˇσ s +2, ˇv s ) and periodic<br />
under (ˇρ s , d 0ˇσ s , ˇv s ) → (ˇρ s , ˇσ s , ˇv s + 2), (ˇρ s + 1, ˇσ s + 1, ˇv s + 1). We can now repeat the analysis of<br />
this section for this set of dyons. The results are more or less identical except for some relative<br />
minus signs between the terms in the curly brackets in eqs.(4.5.3.10)-(4.5.3.12) and the second<br />
equation in (4.5.3.22).<br />
4.5.4 Dyons in ZZ 2 CHL orbifold with twisted sector electric charge<br />
We now consider a Z 2 CHL orbifold defined as follows [55, 56]. We begin with E 8 × E 8<br />
heterotic string theory on T 4 × S 1 × ˜S 1 with S 1 and ˜S 1 labelled by coordinates with period<br />
4π and 2π respectively, and take a quotient of the theory by a Z 2 symmetry that involves<br />
2π shift along S 1 together with an exchange of the two E 8 factors. In the four dimensional