# Sources that explain strings between two branes, where one brane ends on the other

I can't seem to find a source that explains what happens when there are strings between one brane and another brane, where one brane ends on the other brane. For example, consider a D3-brane ending on an NS5-brane. Can anybody point me to a source that explains how to interpret the strings between the two, or if such strings are even permitted. If such strings are permitted what are the resulting fields on the NS5-brane and on the D3-brane?

Edit: As @OON has pointed out in the comments below, fundamental strings don't end on NS5-branes. I would be very grateful if some source describing strings between two D-branes, where one D-brane ends on another D-brane, could be provided. Would the spectrum be the same as for two intersecting D-branes?

• I should note: I've found plenty of sources explaining strings between intersecting branes, but in the brane configurations I've studied, strings between branes ending on another brane never seem to be mentioned. I guess this means they aren't permitted for some reason. – Siraj R Khan Sep 11 '15 at 12:16
• Well I don't feel qualified to give proper answer but as I understand fundamental string can't end on NS5-brane. After all it's not a D5-brane but its S-dual. On the other hand D-string can attach itself both to D3-branes AND NS5-branes. So you should be able to consider not fundamental but D-string between these branes and I suppose get some states localized on the ending of D3 on NS5 similar to the states on D-brane intersections. Take however everything I wrote with a grain of salt (maybe it is mostly bullshit=P) – OON Sep 17 '15 at 13:20
• Thanks for the comment @OON, it seems plausible to me! A cursory search hasn't returned anything about fundamental strings ending on NS5-branes. The source ["Strings 2001: Proceedings of the Strings 2001 Conference, Tata Institute of Fundamental Research, Mumbai, India, January 5-10, 2001" page 163] talks about how the theory on two NS5-branes are determined by D-branes stretched between the two, and the theory on a D-brane is determined by fundamental strings beginning and ending on it. I'll add a bit to my original question asking for a greater focus on D-branes ending on other D-branes. – Siraj R Khan Sep 17 '15 at 14:31