Mass spectrum of Type I string theory

Question

I understand that the massless fields of the Type I string theory are the described by: [\begin{array}{*{20}{c}} {{\rm{Sector}}}&{{\rm{Massless fields}}}\\ {{\rm{R - R}}}&{{C_0}}\\ {{\rm{NS - NS}}}&{{g_{\mu \nu }},\Phi }\\ {{\rm{R - NS}}}&{{\Psi _\mu }}\\ {{\rm{NS - R}}}&{\lambda'}\\ {\rm{R}}&{}\\ {{\rm{NS}}}&{} \end{array}]

I have 6 questions:

1. Are there any (massless) fields in the R and NS sectors (open strings)?

2. What is the projection of state vectors from the Type IIB string theory to the Type I string theory?

3. Is putting the ' necessary in the NS - R sector massless field?

4. What exactly are the spectra of state vectors (in terms of $\mathbf{8}_s$, $\mathbf{8}_v$ etc.) in the Type I string theory?

5. If the Type I string theory is a projection of the Type IIB string theory, where do the open strings come from?

6. What is the mass spectrum of the Type I string theory?

Thanks in advance! 

Answer 1

1. Yes, the gauginos and gauge bosons, respectively.

2. Orientifold projection, as described in any textbook.

3. It's just a notation, convention.

4. The representations are clear from the indices in the notation and described in any textbook.

5. Open strings aren't considered projections of closed strings here; they're an independent sector. Projected closed strings are unorientable closed string.

6. A Hagedorn tower described in any textbook.

This post imported from StackExchange Physics at 2014-03-07 16:41 (UCT), posted by SE-user Luboš Motl

Comments

@Lubos Motl: Thanks a lot.

This post imported from StackExchange Physics at 2014-03-07 16:41 (UCT), posted by SE-user Dimensio1n0