Two photon collisions offer a variety of physics phenomena that can be studied at future electron-positron colliders. Using the planned CEPC parameters as a benchmark, we consider several topics within two-photon collisions. With the full integrated luminosity, Higgs boson photoproduction can be reliably observed, and large statistics on various quarkonium states can be collected. The LEP results for the photon structure function and tau lepton anomalous magnetic moment can be improved by 1-2 orders of magnitude.

We study the deep inelastic scattering (DIS) of a proton-targeted lepton in the presence of gluon condensation using gauge/gravity duality. We use a modified ${\rm AdS}_5$ background where the modification parameter c corresponds to the gluon condensation in the boundary theory. First, by examining the electromagnetic field, we establish that a non-zero c can increase field magnitude. Our aim is to obtain the acceptable value of c for this scattering. Our method is based on setting the mass of the proton as an eigenvalue of the baryonic state equations of the DIS to find the acceptable value of the parameter c on the other side of the equations. Therefore, in the second step, we calculate wave function equations for the baryonic states where the mass of the proton target requires a value contribution of c as ${\rm AdS}_5$ . Proceeding with the electromagnetic field and baryonic states, we derive the holographic interaction action related to the amplitude of the scattering. Finally, we compute the corresponding structure functions numerically as functions of x and q, which are Björken variables and the lepton momentum transfers, respectively. Comparing the Jlab Hall C data with our theoretical calculations, our results are acceptable.

{p=This chapter synthesises the findings from our research and introduces a new framework for discussing and evaluating failure in relation to cultural participation projects and policies. In it, we argue for the importance of acknowledging that any given project or policy can succeed or fail in different facets, to different degrees, for different people, and over different timescales. We then offer some thoughts about how the policymaking process might adapt to encourage greater recognition of this complexity, including the inevitable presence of failures., h1=Abstract}

{p=This chapter examines the purpose of cultural participation policies from the perspective of those who design and deliver them. It considers whether policymakers are open to the possibility of failure, both in terms of those whom they fund but also in relation to their own work and asks whether the context within which they work may support or hinder this openness. Finally, this chapter considers the types of failure that are acknowledged and how we can address learning from these failures that do occur. Throughout this chapter, we return to Creative People and Places as an example of policy in practice to illustrate key points in our analysis., h1=Abstract}